Patent Publication Number: US-2022233632-A1

Title: Modulators of complement activity

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/466,165 filed Jun. 3, 2019, which is a 35 U.S.C. § 371 U.S. National Stage Entry of International Application Number PCT/US2017/065005 filed Dec. 7, 2017, which claims the benefit of priority of U.S. Provisional Patent Application No. 62/430,959 filed on Dec. 7, 2016 entitled “Modulators of Complement Activity”, U.S. Provisional Application No. 62/491,702 filed on Apr. 28, 2017 entitled “Modulators of Complement Activity”, U.S. Provisional Application No. 62/525,284 filed on Jun. 27, 2017 entitled “Modulators of Complement Activity”, and U.S. Provisional Application No. 62/555,711 filed on Sep. 8, 2017 entitled “Modulators of Complement Activity,” the contents of each of which are herein incorporated by reference in their entirety. 
    
    
     SEQUENCE LISTING 
     The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Aug. 12, 2021, is named 2011_1022USCON_SL.txt and is 1,537 bytes in size. 
     BACKGROUND 
     The vertebrate immune response is comprised of adaptive and innate immune components. While the adaptive immune response is selective for particular pathogens and is slow to respond, components of the innate immune response recognize a broad range of pathogens and respond rapidly upon infection. One such component of the innate immune response is the complement system. 
     The complement system includes about 20 circulating complement component proteins, synthesized primarily by the liver. Components of this particular immune response were first termed “complement” due to the observation that they complemented the antibody response in the destruction of bacteria. These proteins remain in an inactive form prior to activation in response to infection. Activation occurs by way of a pathway of proteolytic cleavage initiated by pathogen recognition and leading to pathogen destruction. Three such pathways are known in the complement system and are referred to as the classical pathway, the lectin pathway, and the alternative pathway. The classical pathway is activated when an IgG or IgM molecule binds to the surface of a pathogen. The lectin pathway is initiated by the mannan-binding lectin protein recognizing the sugar residues of a bacterial cell wall. The alternative pathway remains active at low levels in the absence of any specific stimuli. While all three pathways differ with regard to initiating events, all three pathways converge with the cleavage of complement component C3. C3 is cleaved into two products termed C3a and C3b. Of these, C3b becomes covalently linked to the pathogen surface while C3a acts as a diffusible signal to promote inflammation and recruit circulating immune cells. Surface-associated C3b forms a complex with other components to initiate a cascade of reactions among the later components of the complement system. Due to the requirement for surface attachment, complement activity remains localized and minimizes destruction to non-target cells. 
     Pathogen-associated C3b facilitates pathogen destruction in two ways. In one pathway, C3b is recognized directly by phagocytic cells and leads to engulfment of the pathogen. In the second pathway, pathogen-associated C3b initiates the formation of the membrane attack complex (MAC). In the first step, C3b complexes with other complement components to form the C5-convertase complex. Depending on the initial complement activation pathway, the components of this complex may differ. C5-convertase formed as the result of the classical complement pathway comprises C4b and C2a in addition to C3b. When formed by the alternative pathway, C5-convertase comprises two subunits of C3b as well as one Bb component. 
     Complement component C5 is cleaved by either C5-convertase complex into C5a and C5b. C5a, much like C3a, diffuses into the circulation and promotes inflammation, acting as a chemoattractant for inflammatory cells. C5b remains attached to the cell surface where it triggers the formation of the MAC through interactions with C6, C7, C8 and C9. The MAC is a hydrophilic pore that spans the membrane and promotes the free flow of fluid into and out of the cell, thereby destroying it. 
     An important component of all immune activity is the ability of the immune system to distinguish between self and non-self cells. Pathology arises when the immune system is unable to make this distinction. In the case of the complement system, vertebrate cells express proteins that protect them from the effects of the complement cascade. This ensures that targets of the complement system are limited to pathogenic cells. Many complement-related disorders and diseases are associated with abnormal destruction of self cells by the complement cascade. In one example, subjects suffering from paroxysmal nocturnal hemoglobinuria (PNH) are unable to synthesize functional versions of the complement regulatory proteins CD55 and CD59 on hematopoietic stem cells. This results in complement-mediated hemolysis and a variety of downstream complications. Other complement-related disorders and diseases include, but are not limited to autoimmune diseases and disorders; neurological diseases and disorders; blood diseases and disorders; and infectious diseases and disorders. Experimental evidence suggests that many complement-related disorders are alleviated through inhibition of complement activity. Therefore, there is a need for compositions and methods for selectively blocking complement-mediated cell destruction to treat related indications. The present invention meets this need by providing related compositions and methods. 
     SUMMARY OF THE INVENTION 
     In some embodiments, the present disclosure provides a method of treating paroxysmal nocturnal hemoglobinuria (PNH) in a subject, wherein the subject has not been previously treated with eculizumab, the method comprising: administering R5000 to the subject at an initial loading dose and administering R5000 to the subject at an initial treatment dose, wherein the initial treatment dose is administered two or more times at regular intervals after the initial loading dose. Lactate dehydrogenase (LDH) levels in the subject may be monitored over the course of treatment. The initial treatment dose may be substituted with a modified treatment dose of R5000 after two weeks or more of administration with the initial treatment dose. The modified treatment dose of R5000 may include an increased dose of R5000. The initial treatment dose may be substituted with the modified treatment dose when subject LDH levels are equal to or less than 1.5 times the upper limit normal. The initial loading dose may include from about 0.1 mg/kg to about 0.6 mg/kg R5000. The initial treatment dose may include from about 0.1 mg/kg to about 0.3 mg/kg R5000. The initial treatment dose may be substituted with a modified treatment dose of from about 0.3 mg/kg to about 0.6 mg/kg R5000. Hemolysis in subject serum may be reduced. No adverse events may be observed. At least one administration of R5000 may include self-administration. The self-administration may be monitored. The self-administration may be remotely monitored. The self-administration may be monitored using a smart device. The regular intervals may be from about every 12 hours to about every 168 hours. 
     Methods of the present disclosure may include a method of treating PNH in a subject, wherein the subject is currently under treatment with eculizumab or has previously received treatment with eculizumab, the method including administering R5000 to the subject. Residual hemolytic activity in the subject may be reduced or eliminated. Association between C5 and alternative pathway C5-convertase may be inhibited. R5000 may be co-administered with eculizumab. The subject may carry a C5 polymorphism. The polymorphism may include p.Arg885His. 
     In some embodiments, the present disclosure provides a pharmaceutical composition comprising R5001 and at least one pharmaceutically acceptable excipient. The at least one pharmaceutically acceptable excipient may include at least one of sodium chloride and sodium phosphate. The pharmaceutical composition may include from about 25 mM to about 100 mM sodium chloride. The pharmaceutical composition may include from about 10 mM to about 100 mM sodium phosphate. R5001 may be present at a concentration of from about 1 mg/mL to about 400 mg/mL. 
     In some aspects, the present disclosure provides a method of treating PNH in a subject, the method including administering a pharmaceutical composition described herein. The subject may have been treated previously with an antibody-based therapeutic. The subject may be resistant or unresponsive to treatment with the antibody-based therapeutic. The antibody-based therapeutic may be eculizumab. The pharmaceutical composition may be administered at a dose of from about 0.01 mg/kg to about 10 mg/kg. The pharmaceutical composition may be administered at a dose of from about 0.1 mg/kg to about 0.3 mg/kg. The pharmaceutical composition may be administered daily for at least two days. The pharmaceutical composition may be administered daily for about 12 weeks. The pharmaceutical composition may be administered daily for at least 1 year. The pharmaceutical composition may be administered subcutaneously or intravenously. 
     In some embodiments, the present disclosure provides a method of inhibiting binding of C5 to alternative pathway C5 convertase by contacting C5 with R5001. The C5 may be from a subject with a C5 polymorphism. The C5 polymorphism may include p.Arg885His. 
     In some aspects, the present disclosure provides a method of inhibiting residual C5 activity in a subject with PNH, wherein the subject is currently under treatment with eculizumab or has previously received treatment with eculizumab, the method including administering R5000 to the subject. Association between C5 and alternative pathway C5-convertase may be inhibited. R5000 may be co-administered with eculizumab. The subject may carry a C5 polymorphism. The polymorphism may include p.Arg885His. 
     In some embodiments, the present disclosure provides a method of measuring C5 levels in a sample, the method including: immobilizing a capture agent on a substrate, wherein the capture agent binds to a site on C5 that is distinct from the eculizumab binding site; contacting the substrate with the sample, wherein the immobilized capture agent binds to C5 in the sample; contacting the substrate with a detection agent, wherein the detection agent binds to C5 bound to the immobilized capture agent; and measuring the level of bound detection agent as an indicator of C5 levels in the sample. The detection agent may include a detectable label. The detection agent may be detected using a secondary detection agent. The detection agent may include an anti-C5 antibody. Both free C5 levels and eculizumab-associated C5 levels may be measured. The substrate may be contacted with a second detection agent, wherein the second detection agent binds to eculizumab, and wherein the method includes measuring the level of bound second detection agent as an indicator of eculizumab-associated C5 levels. The second detection agent may include a detectable label. The second detection agent may be detected using a secondary detection agent. The capture agent may include a variant of R5000. The R5000 variant may include an N-terminal biotinylated PEG moiety and a substitution of the C-terminal lysine of R5000 with norvaline in the R5000 variant. 
     Methods of the present disclosure may include a method of measuring free eculizumab levels in a sample, the method including: immobilizing a capture agent on a substrate, wherein the capture agent binds to a site on C5 that is distinct from the eculizumab binding site; contacting the substrate with an excess of C5 to form a C5-capture agent complex, wherein the C5-capture agent complex comprises immobilized C5; contacting the substrate with the sample, wherein the immobilized C5 binds to eculizumab in the sample; contacting the substrate with a detection agent, wherein the detection agent binds to eculizumab; and measuring the level of bound detection agent as an indicator of free eculizumab levels in the sample. The capture agent may include a variant of R5000. The R5000 variant may include an N-terminal biotinylated PEG moiety and a substitution of the C-terminal lysine of R5000 with norvaline in the R5000 variant. The detection agent may be an antibody. The detection agent may include a detectable label. The detection agent may be detected using a secondary detection agent. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The foregoing and other objects, features and advantages will be apparent from the following description of particular embodiments of the invention, as well as the accompanying drawings illustrating the principles of various embodiments of the invention. 
         FIG. 1  is a scatter plot showing R5000 inhibition of C5a production. 
         FIG. 2  is a scatter plot showing R5000 inhibition of membrane attack complex formation. 
         FIG. 3  is a scatter plot showing R5000 inhibitor activity in a Cynomolgus monkey model. 
         FIG. 4  is a scatter plot showing pharmacokinetic and pharmacodynamic correlation of R5000 in male Cynomolgus monkeys following multiple subcutaneous administrations at 0.21 mg/kg. 
         FIG. 5  is a scatter plot showing pharmacokinetic and pharmacodynamic correlation of R5000 in male Cynomolgus monkeys following multiple subcutaneous administrations at 4.2 mg/kg. 
         FIG. 6  is a line graph showing concentrations of R5000 in Cynomolgus monkey after a first dose in a repeat-dose toxicology study. 
         FIG. 7  is a line graph showing concentrations of R5000 in Cynomolgus monkey after the last dose in a repeat-dose toxicology study. 
         FIG. 8  is a graph showing predicted R5000 plasma concentrations in man with daily dosing of R5000. 
         FIG. 9A  is a graph showing R5000 dose-dependent maximum plasma concentration levels in a single-ascending-dose clinical study in humans. 
         FIG. 9B  is a graph showing plasma concentrations over time after single dose administration of R5000. 
         FIG. 10A  is a graph showing percent hemolysis over time after single dose administration of R5000 over the duration of 4 days in humans. 
         FIG. 10B  is a graph showing percent CH 50  over time after single dose administration of R5000 in humans. 
         FIG. 10C  is a graph showing percent hemolysis with various doses over the duration of 28 days in humans. 
         FIG. 11  is a graph showing percent complement activity over time after a single dose administration of R5000 in humans. 
         FIG. 12A  is a graph showing changes in percent hemolysis in relation to R5000 concentration in a multi-dose human study. 
         FIG. 12B  is a graph showing plasma concentrations of R5000 over time in a multi-dose human study. 
         FIG. 13A  is a graph showing changes in complement activity over time with R5000 treatment in a multi-dose human study. 
         FIG. 13B  is a graph showing changes in complement activity over an extended period with R5000 treatment in a multi-dose human study. 
         FIG. 14  is a graph showing the predicted drug plasma concentration and hemolysis inhibition with R5000 in humans. 
         FIG. 15  is graph showing predicted pharmacokinetics and pharmacodynamics of R5000 in humans. 
         FIG. 16A  is a graph showing hemolysis in R5000 single dose cohorts of healthy human volunteers. 
         FIG. 16B  is a graph showing predicted percent trough plasma concentrations with and without a loading dose of R5000. 
         FIG. 16C  is a graph showing predicted hemolysis inhibition with 0.1 mg/kg R5000 in humans. 
         FIG. 17  is a graph showing reduced hemolysis by mR5000 in patient samples. 
         FIG. 18A  is a graph showing percent hemolysis in patient samples over the course of six weeks of treatment with R5000. 
         FIG. 18B  is a graph showing changes in hemoglobin levels in patient samples over the course of seven weeks of treatment with R5000. 
         FIG. 18C  is a pair of graphs showing changes in patient lactate dehydrogenase (LDH) levels (individual and combined averages) over the course of seven weeks of treatment with R5000. 
         FIG. 18D  is a graph showing levels of R5000 in patient samples over the course of six weeks of treatment with R5000. 
         FIG. 19  is a graph showing response units over time generated during surface plasmon resonance analysis of C5 inhibitor binding. 
         FIG. 20  is a graph showing percent hemolysis of PNH patient erythrocytes in the presence of R5000 or eculizumab. 
         FIG. 21  is a graph showing percent hemolysis of PNH patient erythrocytes in the presence of R5000 or eculizumab. 
         FIG. 22  is a graph showing percent hemolysis in erythrocytes carrying recombinant C5 containing a known polymorphism p.Arg885His after exposure to various concentrations of eculizumab or R5000. 
         FIG. 23  is a graph showing concentration of C5, C5:eculizumab, and eculizumab in PNH patient serum. 
         FIG. 24  is a graph showing percent residual hemolysis in eculizumab-treated PNH patient plasma in the presence of R5000 or additional eculizumab. 
     
    
    
     DETAILED DESCRIPTION 
     I. Compounds and Compositions 
     In some embodiments, the present disclosure provides compounds and compositions which function to modulate complement activity. Such compounds and compositions may include inhibitors that block complement activation. As used herein, “complement activity” includes the activation of the complement cascade, the formation of cleavage products from a complement component such as C3 or C5, the assembly of downstream complexes following a cleavage event, or any process or event attendant to, or resulting from, the cleavage of a complement component, e.g., C3 or C5. Complement inhibitors may include C5 inhibitors that block complement activation at the level of complement component C5. C5 inhibitors may bind C5 and prevent its cleavage, by C5 convertase, into the cleavage products C5a and C5b. As used herein, “Complement component C5” or “C5” is defined as a complex which is cleaved by C5 convertase into at least the cleavage products, C5a and C5b. “C5 inhibitors,” according to the invention, comprise any compound or composition that inhibits the processing or cleavage of the pre-cleaved complement component C5 complex or the cleavage products of the complement component C5. 
     It is understood that inhibition of C5 cleavage prevents the assembly and activity of the cytolytic membrane attack complex (MAC) on glycosylphosphatidylinositol (GPI) adherent protein-deficient erythrocytes. In some cases, C5 inhibitors presented herein may also bind C5b, preventing C6 binding and subsequent assembly of the C5b-9 MAC. 
     Peptide-Based Compounds 
     In some embodiments, C5 inhibitors of the present disclosure are polypeptides. According to the present invention, any amino acid-based molecule (natural or unnatural) may be termed a “polypeptide” and this term embraces “peptides,” “peptidomimetics,” and “proteins.” “Peptides” are traditionally considered to range in size from about 4 to about 50 amino acids. Polypeptides larger than about 50 amino acids are generally termed “proteins.” 
     C5 inhibitor polypeptides may be linear or cyclic. Cyclic polypeptides include any polypeptides that have as part of their structure one or more cyclic features such as a loop and/or an internal linkage. In some embodiments, cyclic polypeptides are formed when a molecule acts as a bridging moiety to link two or more regions of the polypeptide. As used herein, the term “bridging moiety” refers to one or more components of a bridge formed between two adjacent or non-adjacent amino acids, unnatural amino acids or non-amino acids in a polypeptide. Bridging moieties may be of any size or composition. In some embodiments, bridging moieties may comprise one or more chemical bonds between two adjacent or non-adjacent amino acids, unnatural amino acids, non-amino acid residues or combinations thereof. In some embodiments, such chemical bonds may be between one or more functional groups on adjacent or non-adjacent amino acids, unnatural amino acids, non-amino acid residues or combinations thereof. Bridging moieties may include one or more of an amide bond (lactam), disulfide bond, thioether bond, aromatic ring, triazole ring, and hydrocarbon chain. In some embodiments, bridging moieties include an amide bond between an amine functionality and a carboxylate functionality, each present in an amino acid, unnatural amino acid or non-amino acid residue side chain. In some embodiments, the amine or carboxylate functionalities are part of a non-amino acid residue or unnatural amino acid residue. 
     C5 inhibitor polypeptides may be cyclized through the carboxy terminus, the amino terminus, or through any other convenient point of attachment, such as, for example, through the sulfur of a cysteine (e.g., through the formation of disulfide bonds between two cysteine residues in a sequence) or any side-chain of an amino acid residue. Further linkages forming cyclic loops may include, but are not limited to, maleimide linkages, amide linkages, ester linkages, ether linkages, thiol ether linkages, hydrazone linkages, or acetamide linkages. 
     In some embodiments, cyclic C5 inhibitor polypeptides of the invention are formed using a lactam moiety. Such cyclic polypeptides may be formed, for example, by synthesis on a solid support Wang resin using standard Fmoc chemistry. In some cases, Fmoc-ASP(allyl)-OH and Fmoc-LYS(alloc)-OH are incorporated into polypeptides to serve as precursor monomers for lactam bridge formation. 
     C5 inhibitor polypeptides of the invention may be peptidomimetics. A “peptidomimetic” or “polypeptide mimetic” is a polypeptide in which the molecule contains structural elements that are not found in natural polypeptides (i.e., polypeptides comprised of only the 20 proteinogenic amino acids). In some embodiments, peptidomimetics are capable of recapitulating or mimicking the biological action(s) of a natural peptide. A peptidomimetic may differ in many ways from natural polypeptides, for example through changes in backbone structure or through the presence of amino acids that do not occur in nature. In some cases, peptidomimetics may include amino acids with side chains that are not found among the known 20 proteinogenic amino acids; non-polypeptide-based bridging moieties used to effect cyclization between the ends or internal portions of the molecule; substitutions of the amide bond hydrogen moiety by methyl groups (N-methylation) or other alkyl groups; replacement of a peptide bond with a chemical group or bond that is resistant to chemical or enzymatic treatments; N- and C-terminal modifications; and/or conjugation with a non-peptidic extension (such as polyethylene glycol, lipids, carbohydrates, nucleosides, nucleotides, nucleoside bases, various small molecules, or phosphate or sulfate groups). 
     As used herein, the term “amino acid” includes the residues of the natural amino acids as well as unnatural amino acids. The 20 natural proteinogenic amino acids are identified and referred to herein by either the one-letter or three-letter designations as follows: aspartic acid (Asp:D), isoleucine threonine (Thr:T), leucine (Leu:L), serine (Ser:S), tyrosine (Tyr:Y), glutamic acid (Glu:E), phenylalanine (Phe:F), proline (Pro:P), histidine (His:H), glycine (Gly:G), lysine (Lys:K), alanine (Ala:A), arginine (Arg:R), cysteine (Cys:C), tryptophan (Trp:W), valine (Val:V), glutamine (Gln:Q) methionine (Met:M), asparagine (Asn:N). Naturally occurring amino acids exist in their levorotary (L) stereoisomeric forms. Amino acids referred to herein are L-stereoisomers except where otherwise indicated. The term “amino acid” also includes amino acids bearing a conventional amino protecting group (e.g. acetyl or benzyloxycarbonyl), as well as natural and unnatural amino acids protected at the carboxy terminus (e.g., as a (C1-C6) alkyl, phenyl or benzyl ester or amide; or as an alpha-methylbenzyl amide). Other suitable amino and carboxy protecting groups are known to those skilled in the art (See for example, Greene, T. W.; Wutz, P. G. M., Protecting Groups In Organic Synthesis; second edition, 1991, New York, John Wiley &amp; sons, Inc., and documents cited therein, the contents of each of which are herein incorporated by reference in their entirety). Polypeptides and/or polypeptide compositions of the present invention may also include modified amino acids. 
     “Unnatural” amino acids have side chains or other features not present in the 20 naturally-occurring amino acids listed above and include, but are not limited to: N-methyl amino acids, N-alkyl amino acids, alpha, alpha substituted amino acids, beta-amino acids, alpha-hydroxy amino acids, D-amino acids, and other unnatural amino acids known in the art (See, e.g., Josephson et al., (2005) J. Am. Chem. Soc. 127: 11727-11735; Forster, A. C. et al. (2003) Proc. Natl. Acad. Sci. USA 100: 6353-6357; Subtelny et al., (2008) J. Am. Chem. Soc. 130: 6131-6136; Hartman, M. C. T. et al. (2007) PLoS ONE 2:e972; and Hartman et al., (2006) Proc. Natl. Acad. Sci. USA 103:4356-4361). Further unnatural amino acids useful for the optimization of polypeptides and/or polypeptide compositions of the present invention include, but are not limited to 1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid, 1-amino-2,3-hydro-1H-indene-1-carboxylic acid, homolysine, homoarginine, homoserine, 2-aminoadipic acid, 3-aminoadipic acid, beta-alanine, aminopropionic acid, 2-aminobutyric acid, 4-aminobutyric acid, 5-aminopentanoic acid, 5-aminohexanoic acid, 6-aminocaproic acid, 2-aminoheptanoic acid, 2-aminoisobutyric acid, 3-aminoisobutyric acid, 2-aminopimelic acid, desmosine, 2,3-diaminopropionic acid, N-ethylglycine, N-ethylasparagine, homoproline, hydroxylysine, allo-hydroxylysine, 3-hydroxyproline, 4-hydroxyproline, isodesmosine, allo-isoleucine, N-methylpentylglycine, naphthylalanine, ornithine, pentylglycine, thioproline, norvaline, tert-butylglycine, phenylglycine, azatryptophan, 5-azatryptophan, 7-azatryptophan, 4-fluorophenylalanine, penicillamine, sarcosine, homocysteine, 1-aminocyclopropanecarboxylic acid, 1-aminocyclobutanecarboxylic acid, 1-aminocyclopentanecarboxylic acid, 1-aminocyclohexanecarboxylic acid, 4-aminotetrahydro-2H-pyran-4-carboxylic acid, (S)-2-amino-3-(1H-tetrazol-5-yl)propanoic acid, cyclopentylglycine, cyclohexylglycine, cyclopropylglycine, mw-methyl-arginine, 4-chlorophenylalanine, 3-chlorotyrosine, 3-fluorotyrosine, 5-fluorotryptophan, 5-chlorotryptophan, citrulline, 4-chloro-homophenylalanine, homophenylalanine, 4-aminomethyl-phenylalanine, 3-aminomethyl-phenylalanine, octylglycine, norleucine, tranexamic acid, 2-amino pentanoic acid, 2-amino hexanoic acid, 2-amino heptanoic acid, 2-amino octanoic acid, 2-amino nonanoic acid, 2-amino decanoic acid, 2-amino undecanoic acid, 2-amino dodecanoic acid, aminovaleric acid, and 2-(2-aminoethoxy)acetic acid, pipecolic acid, 2-carboxy azetidine, hexafluoroleucine, 3-Fluorovaline, 2-amino-4,4-difluoro-3-methylbutanoic acid, 3-fluoro-isoleucine, 4-fluoroisoleucine, 5-fluoroisoleucine, 4-methylphenylglycine, 4-ethyl-phenylglycine, 4-isopropyl-phenyislycine, (S)-2-amino-5-azidopentanoic acid (also referred to herein as “X02”), (S)-2-aminohept-6-enoic acid (also referred to herein as “X30”), (S)-2-aminopent-4-ynoic acid (also referred to herein as “X31”), (S)-2-aminopent-4-enoic acid (also referred to herein as “X12”), (S)-2-amino-5-(3-methylguanidino) pentanoic acid, (S)-2-amino-3-(4-(aminomethyl)phenyl)propanoic acid, (S)-2-amino-3-(3-(aminomethyl)phenyl)propanoic acid, (S)-2-amino-4-(2-aminobenzo[d]oxazol-5-yl)butanoic acid, (S)-leucinol, (S)-valinol, (S)-tert-leucinol, (R)-3-methylbutan-2-amine, (S)-2-methyl-1-phenylpropan-1-amine, and (S)-N,2-dimethyl-1-(pyridin-2-yl)propan-1-amine, (S)-2-amino-3-(oxazol-2-yl)propanoic acid, (S)-2-amino-3-(oxazol-5-yl)propanoic acid, (S)-2-amino-3-(1,3,4-oxadiazol-2-yl)propanoic acid, (S)-2-amino-3-(1,2,4-oxadiazol-3-yl)propanoic acid, (S)-2-amino-3-(5-fluoro-1H-indazol-3-yl)propanoic acid, and (S)-2-amino-3-(1H-indazol-3-yl)propanoic acid, (S)-2-amino-3-(oxazol-2-yl)butanoic acid, (S)-2-amino-3-(oxazol-5-yl) butanoic acid, (S)-2-amino-3-(1,3,4-oxadiazol-2-yl) butanoic acid, (S)-2-amino-3-(1,2,4-oxadiazol-3-yl) butanoic acid, (S)-2-amino-3-(5-fluoro-1H-indazol-3-yl) butanoic acid, and (S)-2-amino-3-(1H-indazol-3-yl) butanoic acid, 2-(2′MeOphenyl)-2-amino acetic acid, tetrahydro 3-isoquinolinecarboxylic acid and stereoisomers thereof (including, but not limited, to D and L isomers). 
     Additional unnatural amino acids that are useful in the optimization of polypeptides or polypeptide compositions of the invention include but are not limited to fluorinated amino acids wherein one or more carbon bound hydrogen atoms are replaced by fluorine. The number of fluorine atoms included can range from 1 up to and including all of the hydrogen atoms. Examples of such amino acids include but are not limited to 3-fluoroproline, 3,3-difluoroproline, 4-fluoroproline, 4,4-difluoroproline, 3,4-difluroproline, 3,3,4,4-tetrafluoroproline, 4-fluorotryptophan, 5-flurotryptophan, 6-fluorotryptophan, 7-fluorotryptophan, and stereoisomers thereof. 
     Further unnatural amino acids that are useful in the optimization of polypeptides of the invention include but are not limited to those that are disubstituted at the α-carbon. These include amino acids in which the two substituents on the α-carbon are the same, for example α-amino isobutyric acid, and 2-amino-2-ethyl butanoic acid, as well as those where the substituents are different, for example α-methylphenylglycine and α-methylproline. Further the substituents on the α-carbon may be taken together to form a ring, for example 1-aminocyclopentanecarboxylic acid, 1-aminocyclobutanecarboxylic acid, 1-aminocyclohexanecarboxylic acid, 3-aminotetrahydrofuran-3-carboxylic acid, 3-aminotetrahydropyran-3-carboxylic acid, 4-aminotetrahydropyran-4-carboxylic acid, 3-aminopyrrolidine-3-carboxylic acid, 3-aminopiperidine-3-carboxylic acid, 4-aminopiperidinnne-4-carboxylic acid, and stereoisomers thereof. 
     Additional unnatural amino acids that are useful in the optimization of polypeptides or polypeptide compositions of the invention include but are not limited to analogs of tryptophan in which the indole ring system is replaced by another 9 or 10 membered bicyclic ring system comprising 0, 1, 2, 3 or 4 heteroatoms independently selected from N, O, or S. Each ring system may be saturated, partially unsaturated, or fully unsaturated. The ring system may be substituted by 0, 1, 2, 3, or 4 substituents at any substitutable atom. Each substituent may be independently selected from H, F, Cl, Br, CN, COOR, CONRR′, oxo, OR, NRR′. Each R and R′ may be independently selected from H, C1-C20 alkyl, or C1-C20 alkyl-O—C1-20 alkyl. 
     In some embodiments, analogs of tryptophan (also referred to herein as “tryptophan analogs”) may be useful in the optimization of polypeptides or polypeptide compositions of the invention. Tryptophan analogs may include, but are not limited to 5-fluorotryptophan [(5-F)W], 5-methyl-O-tryptophan [(5-MeO)W], 1-methyltryptophan [(1-Me-W) or (1-Me)W], D-tryptophan (D-Trp), azatryptophan (including, but not limited to 4-azatryptophan, 7-azatryptophan and 5-azatryptophan,) 5-chlorotryptophan, 4-fluorotryptophan, 6-fluorotryptophan, 7-fluorotryptophan, and stereoisomers thereof. Except where indicated to the contrary, the term “azatryptophan” and its abbreviation, “azaTrp,” as used herein, refer to 7-azatryptophan. 
     Modified amino acid residues useful for the optimization of polypeptides and/or polypeptide compositions of the present invention include, but are not limited to those which are chemically blocked (reversibly or irreversibly); chemically modified on their N-terminal amino group or their side chain groups; chemically modified in the amide backbone, as for example, N-methylated, D (unnatural amino acids) and L (natural amino acids) stereoisomers; or residues wherein the side chain functional groups are chemically modified to another functional group. In some embodiments, modified amino acids include without limitation, methionine sulfoxide; methionine sulfone; aspartic acid-(beta-methyl ester), a modified amino acid of aspartic acid; N-ethylglycine, a modified amino acid of glycine; alanine carboxamide; and/or a modified amino acid of alanine. Unnatural amino acids may be purchased from Sigma-Aldrich (St. Louis, Mo.), Bachem (Torrance, Calif.) or other suppliers. Unnatural amino acids may further include any of those listed in Table 2 of US patent publication US 2011/0172126, the contents of which are incorporated herein by reference in their entirety. 
     The present invention contemplates variants and derivatives of polypeptides presented herein. These include substitutional, insertional, deletional, and covalent variants and derivatives. As used herein, the term “derivative” is used synonymously with the term “variant” and refers to a molecule that has been modified or changed in any way relative to a reference molecule or starting molecule. 
     Polypeptides of the invention may include any of the following components, features, or moieties, for which abbreviations used herein include: “Ac” and “NH2” indicate acetyl and amidated termini, respectively; “Nvl” stands for norvaline; “Phg” stands for phenylglycine; “Tbg” stands for tert-butylglycine; “Chg” stands for cyclohexylglycine; “(N-Me)X” stands for the N-methylated form of the amino acid indicated by the letter or three letter amino acid code in place of variable “X” written as N-methyl-X [e.g. (N-Me)D or (N-Me)Asp stand for the N-methylated form of aspartic acid or N-methyl-aspartic acid]; “azaTrp” stands for azatryptophan; “(4-F)Phe” stands for 4-fluorophenylalanine; “Tyr(OMe)” stands for O-methyl tyrosine, “Aib” stands for amino isobutyric acid; “(homo)F” or “(homo)Phe” stands for homophenylalanine; “(2-OMe)Phg” refers to 2-O-methylphenylglycine; “(5-F)W” refers to 5-fluorotryptophan; “D-X” refers to the D-stereoisomer of the given amino acid “X” [e.g. (D-Chg) stands for D-cyclohexylglycine]; “(5-MeO)W” refers to 5-methyl-O-tryptophan; “homoC” refers to homocysteine; “(1-Me-W)” or “(1-Me)W” refers to 1-methyltryptophan; “Nle” refers to norleucine; “Tiq” refers to a tetrahydroisoquinoline residue; “Asp(T)” refers to (S)-2-amino-3-(1H-tetrazol-5-yl)propanoic acid; “(3-Cl-Phe)” refers to 3-chlorophenylalanine; “[(N-Me-4-F)Phe]” or “(N-Me-4-F)Phe” refers to N-methyl-4-fluorophenylalanine; “(m-Cl-homo)Phe” refers to meta-chloro homophenylalanine; “(des-amino)C” refers to 3-thiopropionic acid; “(alpha-methyl)D” refers to alpha-methyl L-aspartic acid; “2Nal” refers to 2-naphthylalanine; “(3-aminomethyl)Phe” refers to 3-aminomethyl-L-phenyalanine; “Cle” refers to cycloleucine; “Ac-Pyran” refers to 4-amino-tetrahydro-pyran-4-carboxylic acid; “(Lys-C16)” refers to N-ε-palmitoyl lysine; “(Lys-C12)” refers to N-ε-lauryl lysine; “(Lys-C10)” refers to N-ε-capryl lysine; “(Lys-C8)” refers to N-ε-caprylic lysine; “[xXylyl(y,z)]” refers to the xylyl bridging moiety between two thiol containing amino acids where x may be m, p or o to indicate the use of meta-, para- or ortho-dibromoxylenes (respectively) to generate bridging moieties and the numerical identifiers, y and z, place the amino acid position within the polypeptide of the amino acids participating in the cyclization; “[cyclo(y,z)]” refers to the formation of a bond between two amino acid residues where the numerical identifiers, y and z, place the position of the residues participating in the bond; “[cyclo-olefinyl(y,z)]” refers to the formation of a bond between two amino acid residues by olefin metathesis where the numerical identifiers, y and z, place the position of the residues participating in the bond; “[cyclo-thioalkyl(y,z)]” refers to the formation of a thioether bond between two amino acid residues where the numerical identifiers, y and z, place the position of the residues participating in the bond; “[cyclo-triazolyl(y,z)]” refers to the formation of a triazole ring between two amino acid residues where the numerical identifiers, y and z, place the position of the residues participating in the bond. “B20” refers to N-ε-(PEG2-γ-glutamic acid-N-α-octadecanedioic acid) lysine [also known as (1S,28S)-1-amino-7,16,25,30-tetraoxo-9,12,18,21-tetraoxa-6,15,24,29-tetraazahexatetracontane-1,28,46-tricarboxylic acid.] 
     
       
         
         
             
             
         
       
     
     “B28” refers to N-ε-(PEG24-γ-glutamic acid-N-α-hexadecanoyl)lysine. 
     
       
         
         
             
             
         
       
     
     “K14” refers to N-ε-1-(4,4-dimethyl-2,6-dioxocyclohex-1-ylidene)-3-methylbutyl-L-lysine. All other symbols refer to the standard one-letter amino acid code. 
     Some C5 inhibitor polypeptides comprise from about 5 amino acids to about 10 amino acids, from about 6 amino acids to about 12 amino acids, from about 7 amino acids to about 14 amino acids, from about 8 amino acids to about 16 amino acids, from about 10 amino acids to about 18 amino acids, from about 12 amino acids to about 24 amino acids, or from about 15 amino acids to about 30 amino acids. In some cases, C5 inhibitor polypeptides comprise at least 30 amino acids. 
     Some C5 inhibitors of the invention include a C-terminal lipid moiety. Such lipid moieties may include fatty acyl groups (e.g., saturated or unsaturated fatty acyl groups). In some cases, the fatty acyl group may be a palmitoyl group. 
     C5 inhibitors having fatty acyl groups may include one or more molecular linkers joining the fatty acids to the peptide. Such molecular linkers may include amino acid residues. In some cases, L-γ glutamic acid residues may be used as molecular linkers. In some cases, molecular linkers may include one or more polyethylene glycol (PEG) linkers. PEG linkers of the invention may include from about 1 to about 5, from about 2 to about 10, from about 4 to about 20, from about 6 to about 24, from about 8 to about 32, or at least 32 PEG units. 
     C5 inhibitors of the invention may have molecular weights of from about 200 g/mol to about 600 g/mol, from about 500 g/mol to about 2000 g/mol, from about 1000 g/mol to about 5000 g/mol, from about 3000 g/mol to about 4000 g/mol, from about 2500 g/mol to about 7500 g/mol, from about 5000 g/mol to about 10000 g/mol, or at least 10000 g/mol. 
     In some embodiments, C5 inhibitor polypeptides of the invention include R5000. The core amino acid sequence of R5000 ([cyclo(1,6)]Ac-K-V-E-R-F-D-(N-Me)D-Tbg-Y-azaTrp-E-Y-P-Chg-K; SEQ ID NO: 1) comprises 15 amino acids (all L-amino acids), including 4 unnatural amino acids [N-methyl-aspartic acid or “(N-Me)D”, tert-butylglycine or “Tbg”, 7-azatryptophan or “azaTrp”, and cyclohexylglycine or “Chg”]; a lactam bridge between K1 and D6 of the polypeptide sequence; and a C-terminal lysine reside with a modified side chain, forming a N-ε-(PEG24-γ-glutamic acid-N-α-hexadecanoyl)lysine residue (also referred to herein as “B28”). The C-terminal lysine side chain modification includes a polyethyleneglycol (PEG) spacer (PEG24), with the PEG24 being attached to an L-γ glutamic acid residue that is derivatized with a palmitoyl group. 
     In some embodiments, the present invention includes variants of R5000. In some R5000 variants, the C-terminal lysine side chain moiety may be altered. In some cases, the PEG24 spacer (having 24 PEG subunits) of the C-terminal lysine side chain moiety may include fewer or additional PEG subunits. In other cases, the palmitoyl group of the C-terminal lysine side chain moiety may be substituted with another saturated or unsaturated fatty acid. In further cases, the L-γ glutamic acid linker of the C-terminal lysine side chain moiety (between PEG and acyl groups) may be substituted with an alternative amino acid or non-amino acid linker. 
     In some embodiments, C5 inhibitors may include active metabolites or variants of R5000. Metabolites may include R5001. As used herein the term “R5001” refers to a variant of R5000 with w-hydroxylation of the palmitoyl tail. R5001 may be synthesized or may be formed by hydroxylation of an R5000 precursor. R5001 may be capable of binding to C5 with an equilibrium dissociation constant (K D ) equal to or similar to that of R5000 binding to C5 (e.g., about ±20% of the K D  of R5000 binding to C5). R5001 may be capable of inhibiting C5 cleavage and/or blocking one or more downstream events associated with C5 cleavage with a half maximal inhibitory concentration (IC 50 ) equal to or similar to that of R5000 (e.g., ±20% of the IC 50  of R5000 for inhibiting C5 cleavage). R5001 may be capable of inhibiting complement-dependent hemolysis with an IC 50  equal to or similar to that of R5000 (e.g., about ±20% of the IC 50  of R5000 for inhibiting hemolysis). 
     In some embodiments, R5000 variants may include modifications to the core polypeptide sequence in R5000 that may be used in combination with one or more of the cyclic or C-terminal lysine side chain moiety features of R5000. Such variants may have at least 50%, at least 55%, at least 65%, at least 70%, at least 80%, at least 85%, at least 90%, or at least 95% sequence identity to the core polypeptide sequence of (SEQ ID NO: 1). 
     In some cases, R5000 variants may be cyclized by forming lactam bridges between amino acids other than those used in R5000. 
     C5 inhibitors of the invention may be developed or modified to achieve specific binding characteristics. Inhibitor binding may be assessed by determining rates of association and/or dissociation with a particular target. In some cases, compounds demonstrate strong and rapid association with a target combined with a slow rate of dissociation. In some embodiments, C5 inhibitors of the invention demonstrate strong and rapid association with C5. Such inhibitors may further demonstrate slow rates of dissociation with C5. 
     C5 inhibitors of the invention that bind to C5 complement protein, may bind to C5 complement protein with an equilibrium dissociation constant (K D ) of from about 0.001 nM to about 0.01 nM, from about 0.005 nM to about 0.05 nM, from about 0.01 nM to about 0.1 nM, from about 0.05 nM to about 0.5 nM, from about 0.1 nM to about 1.0 nM, from about 0.5 nM to about 5.0 nM, from about 2 nM to about 10 nM, from about 8 nM to about 20 nM, from about 15 nM to about 45 nM, from about 30 nM to about 60 nM, from about 40 nM to about 80 nM, from about 50 nM to about 100 nM, from about 75 nM to about 150 nM, from about 100 nM to about 500 nM, from about 200 nM to about 800 nM, from about 400 nM to about 1,000 nM or at least 1,000 nM. 
     In some embodiments, C5 inhibitors of the invention block the formation or generation of C5a from C5. In some case, formation or generation of C5a is blocked following activation of the alternative pathway of complement activation. In some cases, C5 inhibitors of the invention block the formation of the membrane attack complex (MAC). Such MAC formation inhibition may be due to C5 inhibitor binding to C5b subunits. C5 inhibitor binding to C5b subunits may prevent C6 binding, resulting in blockage of MAC formation. In some embodiments, this MAC formation inhibition occurs after activation of the classical, alternative, or lectin pathways. 
     C5 inhibitors of the invention may be synthesized using chemical processes. In some cases, such synthesis eliminates risks associated with the manufacture of biological products in mammalian cell lines. In some cases, chemical synthesis may be simpler and more cost-effective than biological production processes. 
     In some embodiments, C5 inhibitor (e.g., R5000 and/or an active metabolite or variant thereof) compositions may be pharmaceutical compositions comprising at least one pharmaceutically acceptable excipient. In some embodiments, the pharmaceutically acceptable excipient may include at least one of a salt and a buffering agent. The salt may be sodium chloride. The buffering agent may be sodium phosphate. Sodium chloride may be present at a concentration of from about 0.1 mM to about 1000 mM. In some cases, sodium chloride may be present at a concentration of from about 25 mM to about 100 mM. Sodium phosphate may be present at a concentration of from about 0.1 mM to about 1000 mM. In some cases, sodium phosphate is present at a concentration of from about 10 mM to about 100 mM. 
     In some embodiments, C5 inhibitor (e.g., R5000 and/or an active metabolite or variant thereof) compositions may include from about 0.01 mg/mL to about 4000 mg/mL of a C5 inhibitor. In some cases, C5 inhibitors are present at a concentration of from about 1 mg/mL to about 400 mg/mL. 
     Isotopic Variations 
     Polypeptides of the present invention may comprise one or more atoms that are isotopes. As used herein, the term “isotope” refers to a chemical element that has one or more additional neutrons. In one embodiment, polypeptides of the present invention may be deuterated. As used herein, the term “deuterated” refers to a substance that has had one or more hydrogen atoms replaced by deuterium isotopes. Deuterium isotopes are isotopes of hydrogen. The nucleus of hydrogen contains one proton while deuterium nuclei contain both a proton and a neutron. Compounds and pharmaceutical compositions of the present invention may be deuterated in order to change a physical property, such as stability, or to allow them to be used in diagnostic and experimental applications. 
     II. Methods of Use 
     Provided herein are methods of modulating complement activity using compounds and/or compositions of the invention. 
     Therapeutic Indications 
     An important component of all immune activity (innate and adaptive) is the ability of the immune system to distinguish between self and non-self cells. Pathology arises when the immune system is unable to make this distinction. In the case of the complement system, vertebrate cells express inhibitory proteins that protect them from the effects of the complement cascade and this ensures that the complement system is directed against microbial pathogens. Many complement-related disorders and diseases are associated with abnormal destruction of self-cells by the complement cascade. 
     Methods of the invention include methods of treating complement-related disorders with compounds and compositions of the invention. A “complement-related disorder,” as referred to herein, may include any condition related to dysfunction of the complement system, e.g., cleavage or processing of a complement component such as C5. 
     In some embodiments, methods of the invention include methods of inhibiting complement activity in a subject. In some cases, the percentage of complement activity inhibited in a subject may be at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least, 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, or at least 99.9%. In some cases, this level of inhibition and/or maximum inhibition of complement activity may be achieved by from about 1 hour after an administration to about 3 hours after an administration, from about 2 hours after an administration to about 4 hours after an administration, from about 3 hours after an administration to about 10 hours after an administration, from about 5 hours after an administration to about 20 hour after an administration, or from about 12 hours after an administration to about 24 hours after an administration. Inhibition of complement activity may continue throughout a period of at least 1 day, of at least 2 days, of at least 3 days, of at least 4 days, of at least 5 days, of at least 6 days, of at least 7 days, of at least 2 weeks, of at least 3 weeks, or at least 4 weeks. In some cases, this level of inhibition may be achieved through daily administration. Such daily administration may include administration for at least 2 days, for at least 3 days, for at least 4 days, for at least 5 days, for at least 6 days, for at least 7 days, for at least 2 weeks, for at least 3 weeks, for at least 4 weeks, for at least 2 months, for at least 4 months, for at least 6 months, for at least 1 year, or for at least 5 years. In some cases, subjects may be administered compounds or compositions of the present disclosure for the life of such subjects. 
     In some embodiments, methods of the invention include methods of inhibiting C5 activity in a subject. “C5-dependent complement activity” or “C5 activity,” as used herein refers to activation of the complement cascade through cleavage of C5, the assembly of downstream cleavage products of C5, or any other process or event attendant to, or resulting from, the cleavage of C5. In some cases, the percentage of C5 activity inhibited in a subject may be at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least, 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, or at least 99.9%. 
     In some embodiments, methods of the invention may include methods of inhibiting hemolysis by administering one or more compounds or compositions of the invention to a subject or patient in need thereof. According to some such methods, hemolysis may be reduced by from about 25% to about 99%. In other embodiments, hemolysis is reduced by from about 10% to about 40%, from about 25% to about 75%, from about 30% to about 60%, from about 50% to about 90%, from about 75% to about 95%, from about 90% to about 99%, or from about 97% to about 99.5%. In some cases, hemolysis is reduced by at least 50%, 60%, 70%, 80%, 90% or 95%. 
     According to some methods, the percent inhibition of hemolysis is from about ≥90% to about ≥99% (e.g., ≥91%, ≥92%, ≥93%, ≥94%, ≥95%, ≥96%, ≥97%, ≥98%). In some cases, this level of inhibition and/or maximum inhibition of hemolysis may be achieved by from about 1 hour after an administration to about 3 hours after an administration, from about 2 hours after an administration to about 4 hours after an administration, from about 3 hours after an administration to about 10 hours after an administration, from about 5 hours after an administration to about 20 hour after an administration or from about 12 hours after an administration to about 24 hours after an administration. Inhibition of hemolysis activity levels may continue throughout a period of at least 1 day, of at least 2 days, of at least 3 days, of at least 4 days, of at least 5 days, of at least 6 days, of at least 7 days, of at least 2 weeks, of at least 3 weeks, or at least 4 weeks. In some cases, this level of inhibition may be achieved through daily administration. Such daily administration may include administration for at least 2 days, for at least 3 days, for at least 4 days, for at least 5 days, for at least 6 days, for at least 7 days, for at least 2 weeks, for at least 3 weeks, for at least 4 weeks, for at least 2 months, for at least 4 months, for at least 6 months, for at least 1 year, or for at least 5 years. In some cases, subjects may be administered compounds or compositions of the present disclosure for the life of such subjects. 
     C5 inhibitors of the invention may be used to treat one or more indications, wherein few or no adverse effects occur as a result of the C5 inhibitor treatment. In some cases, no adverse cardiovascular, respiratory, and/or central nervous system (CNS) effects occur. In some cases, no changes in heart rate and/or arterial blood pressure occur. In some cases, no changes to respiratory rate, tidal volume, and/or minute volume occur. 
     By “lower” or “reduce” in the context of a disease marker or symptom is meant a significant decrease in such level, often statistically significant. The decrease can be, for example, at least 10%, at least 20%, at least 30%, at least 40% or more, and is preferably down to a level accepted as within the range of normal for an individual without such disorder. 
     By “increase” or “raise” in the context of a disease marker or symptom is meant a significant rise in such level, often statistically significant. The increase can be, for example, at least 10%, at least 20%, at least 30%, at least 40% or more, and is preferably up to a level accepted as within the range of normal for an individual without such disorder. 
     A treatment or preventive effect is evident when there is a significant improvement, often statistically significant, in one or more parameters of disease status, or by a failure to worsen or to develop symptoms where they would otherwise be anticipated. As an example, a favorable change of at least 10% in a measurable parameter of disease, and preferably at least 20%, 30%, 40%, 50% or more can be indicative of effective treatment. Efficacy for a given compound or composition can also be judged using an experimental animal model for the given disease as known in the art. When using an experimental animal model, efficacy of treatment is evidenced when a statistically significant modulation in a marker or symptom is observed. 
     Paroxysmal Nocturnal Hemoglobinuria 
     In some embodiments, provided herein are methods of treating paroxysmal nocturnal hemoglobinuria (PNH) with compounds or compositions, e.g., pharmaceutical compositions, of the invention. PNH is a rare complement-related disorder caused by an acquired mutation in the phosphatidylinositol glycan anchor biosynthesis, class A (PIG-A) gene that originates from a multipotent hematopoietic stem cell (Pu, J. J. et al., Clin Transl Sci. 2011 June; 4(3):219-24). PNH is characterized by bone marrow disorder, hemolytic anemia and thrombosis. The PIG-A gene product is necessary for the production of a glycolipid anchor, glycosylphosphatidylinositol (GPI), utilized to tether proteins to the plasma membrane. Two complement-regulatory proteins responsible for protecting cells from lytic activity of the terminal complement complex, CD55 (decay accelerating factor) and CD59 (membrane inhibitor of reactive lysis), become nonfunctional in the absence of GPI. This leads to C5 activation and accumulation of specific complement proteins on the surface of red blood cells (RBCs) leading to complement-mediated destruction of these cells. 
     Patient with PNH initially present with hemoglobinuria, abdominal pain, smooth muscle dystonias, and fatigue, e.g., PNH-related symptoms or disorders. PNH is also characterized by intravascular hemolysis (the primary clinical manifestation of the disease) and venous thrombosis. Venous thrombosis may occur in unusual sites, including, but not limited to hepatic, mesenteric, cerebral, and dermal veins. (Parker, C. et al., 2005. Blood. 106: 3699-709 and Parker, C. J., 2007. Exp Hematol. 35: 523-33). Currently, eculizumab (SOLIRIS®, Alexion Pharmaceuticals, Cheshire, Conn.), a C5 inhibitor monoclonal antibody, is the only approved treatment for PNH. 
     Treatment with eculizumab results in an adequate control of intravascular hemolysis in most PNH patients (Schrezenmeier, H. et al., 2014. Haematologica. 99: 922-9). However, Nishimura and colleagues have described 11 patients in Japan (3.2% of patients with PNH) who have mutations in the C5 gene that prevent binding of eculizumab to C5 and do not respond to treatment with the antibody (Nishimura, J-I. et al., 2014. N Engl J Med. 370: 632-9). Further, eculizumab is administered every 2 weeks as an IV infusion under the supervision of a healthcare professional, which is inconvenient and poses a burden to patients. 
     Long-term IV administration has the potential to lead to serious complications such as infections, local thrombosis, hematomas, and progressively reduced venous access. Additionally, eculizumab is a large protein, and is associated with risk of immunogenicity and hypersensitivity. Finally, while eculizumab binds C5 and prevents C5b generation, any C5b generated through incomplete inhibition can initiate MAC formation and cause hemolysis. 
     The peripheral blood of patients with PNH can vary in the proportions of normal and abnormal cells. The disease is sub-classified according to the International PNH Interest Group based on clinical features, bone marrow characteristics, and the percentage of GPI-AP-deficient polymorphonuclear leukocytes (PMNs). As GPI-AP-deficient red blood cells are more sensitive to destruction in PNH patients, the flow cytometry analysis of PMNs is considered more informative (Parker, C. J., 2012. Curr Opin Hematol. 19: 141-8). Flow cytometry analysis in classic PNH shows 50 to 100% GPI-AP-deficient PMNs. 
     The hemolytic anemia of PNH is independent of autoantibodies (Coombs negative) and results from uncontrolled activation of the Alternative Pathway (AP) of complement. 
     In some embodiments, compounds and composition, e.g., pharmaceutical compositions, of the present invention are particularly useful in the treatment of PNH. Such compounds and compositions may include C5 inhibitors (e.g., R5000 and/or an active metabolite or variant thereof). C5 inhibitors of the invention, useful for treatment of PNH may, in some cases, block the cleavage of C5 into C5a and C5b. In some cases, C5 inhibitors of the invention may be used as an alternative to eculizumab therapy for PNH. Unlike eculizumab, C5 inhibitors of the invention may bind C5b, preventing C6 binding and subsequent assembly of the C5b-9 MAC. 
     In some cases, R5000 and/or active metabolites or variants thereof, alone or in compositions, may be used to treat PNH in subjects. Such subjects may include subjects that have had adverse effects with, been unresponsive to, demonstrated reduced responsiveness with, or demonstrated resistance to other treatments (e.g., with eculizumab). In some embodiments, treatment with compounds and compositions of the present disclosure may inhibit hemolysis of PNH erythrocytes in a dose dependent manner. 
     In some embodiments, R5000 and/or an active metabolite or variant thereof is administered in combination with eculizumab in a regimen which may involve parallel or serial treatment. 
     Based on sequence and structural data, R5000 and/or active metabolites or variants thereof may be particularly useful for the treatment of PNH in the limited number of patients with polymorphisms in the C5 gene that prevent binding of eculizumab to C5. An example of such patients are those with a single missense C5 heterozygous mutation, c.2654G-&gt;A, which predicts the polymorphism p.Arg885His (R885H; for a description of this and other polymorphisms at position 885, see Nishimura, J. et al., N Engl J Med. 2014. 370(7):632-9, the contents of which are herein incorporated by reference in their entirety). This mutation disrupts the ability of eculizumab to bind to C5 in carriers of the mutation. R5000 and R5001, however, are capable of binding C5 carrying the R885H substitution. Accordingly, in some embodiments, methods of the present disclosure include inhibiting C5 activity and/or treating PNH in subjects carrying the polymorphism p.Arg885His. 
     Like eculizumab, R5000 and R5001 block the proteolytic cleavage of C5 into C5a and C5b. Unlike eculizumab, R5000 and R5001 can also bind to C5b and block association with C6, preventing the subsequent assembly of the MAC. Therefore, advantageously any C5b that arises from incomplete inhibition by R5000 and/or R5001 is prevented from binding C6 and completing assembly of the MAC. 
     In some cases, R5000 and/or active metabolites or variants thereof may be used as a therapeutic alternative to eculizumab for patients with PNH and may offer added efficacy without the inconvenience and liabilities of IV administration and known risks of immunogenicity and hypersensitivity associated with monoclonal antibodies. Further, the serious complications of long-term IV administration, such as infections, loss of venous access, local thrombosis, and hematomas, may be overcome by R5000 and/or R5001 given by subcutaneous (SC) injection. 
     In some embodiments, methods of the present disclosure include treating PNH in subjects that have not been previously treated with eculizumab. Such methods may include administering C5 inhibitors to the subject. The C5 inhibitors may include R5000 and/or metabolites or variants thereof. In some aspects, the C5 inhibitors are administered two or more times at regular intervals. The intervals may be from about every hour to about every 12 hours, from about every 2 hours to about every 24 hours, from about every 4 hours to about every 36 hours, from about every 8 hours to about every 48 hours, from about every 12 hours to about every 60 hours, from about every 18 hours to about every 72 hours, from about every 30 hours to about every 84 hours, from about every 40 hours to about every 96 hours, from about every 50 hours to about every 108 hours, from about every 60 hours to about every 120 hours, from about every 70 hours to about every 132 hours, from about every 80 hours to about every 168 hours, from about every day to about every week, from about every week to about every month, or longer than every month. C5 inhibitor administration may include administering C5 inhibitors at an initial loading dose. The initial loading dose may be from about 0.01 mg/kg to about 1 mg/kg, from about 0.05 mg/kg to about 2 mg/kg, from about 0.1 mg/kg to about 3 mg/kg, from about 0.2 mg/kg to about 4 mg/kg, from about 0.3 mg/kg to about 5 mg/kg, from about 0.6 mg/kg to about 6 mg/kg, from about 1.5 mg/kg to about 10 mg/kg, or from about 5 mg/kg to about 50 mg/kg. C5 inhibitor administration may include administering C5 inhibitors at an initial treatment dose. The initial treatment dose may include administering C5 inhibitors two or more times at regular intervals after the initial loading dose. The initial treatment dose may be from about 0.01 mg/kg to about 1 mg/kg, from about 0.05 mg/kg to about 2 mg/kg, from about 0.1 mg/kg to about 3 mg/kg, from about 0.2 mg/kg to about 4 mg/kg, from about 0.3 mg/kg to about 5 mg/kg, from about 0.6 mg/kg to about 6 mg/kg, from about 1.5 mg/kg to about 10 mg/kg, or from about 5 mg/kg to about 50 mg/kg. Initial treatment doses may be substituted with modified treatment doses after a period of administration with the initial treatment dose. The period may be from about 1 day to about 10 days, from about 1 week to about 3 weeks, from about 2 weeks to about 4 weeks, or more than 4 weeks. The modified treatment dose may be from about 0.01 mg/kg to about 1 mg/kg, from about 0.05 mg/kg to about 2 mg/kg, from about 0.1 mg/kg to about 3 mg/kg, from about 0.2 mg/kg to about 4 mg/kg, from about 0.3 mg/kg to about 5 mg/kg, from about 0.6 mg/kg to about 6 mg/kg, from about 1.5 mg/kg to about 10 mg/kg, or from about 5 mg/kg to about 50 mg/kg. The modified treatment dose may include an increase in C5 inhibitor levels administered. Lactate dehydrogenase (LDH) levels in the subject may be monitored over the course of treatment. Initial treatment doses may be substituted with modified treatment doses based on changes in LDH levels observed. In some aspects, subjects are transitioned to a modified treatment dose after LDH levels equal to or less than 1.5 times the upper limit normal are detected. In some embodiments, hemolysis in subject serum is reduced. In some embodiments, no adverse events (e.g., injection reactions or systemic infections) are observed in response to treatment. C5 inhibitor administration may include self-administration (e.g., using an auto-injector device). The self-administration may be monitored, for example, by a medical professional. In some aspects, the self-administration may be remotely monitored. Monitoring may be carried out using a smart device. 
     It has been reported that eculizumab does not completely abolish C5 activity in vitro under conditions that mimic strong activation, potentially leaving patients vulnerable to inadequate disease control (see Brodsky et al., 2017. Blood 129; 922-923 and Harder et al., 2017. Blood. 129:970-980). This is referred to as residual C5 activity. Residual C5 activity may be due to inability of eculizumab to prevent C5 association with the alternative pathway C5-convertase (comprising two subunits of C3b as well as one Bb component). In some embodiments, R5000 and/or active metabolites or variants thereof may be used to inhibit association between C5 and alternative pathway C5-convertase. 
     Residual C5 activity may also exist where strong complement activation results in C5 cleavage before eculizumab can bind. Like eculizumab, R5000 and active metabolites or variants thereof bind to C5 and inhibit cleavage of C5 and activation of the terminal complement cascade. R5000 and R5001, however, bind C5 at a different site than eculizumab and therefore have a distinct molecular mechanism of inhibition. Further, R5000 and R5001 may associate with C5b after cleavage to prevent subsequent hemolysis. In some embodiments, R5000 and/or active metabolites or variants thereof may be used to improve complement inhibition under conditions where some hemolytic activity persists during or after treatment with eculizumab. Accordingly, in some embodiments, the present disclosure provides methods of inhibiting residual C5 activity by contacting C5 with R5000 and/or an active metabolite thereof. The C5 may be C5 of a subject with PNH. The C5 may be C5 of a subject with a C5 polymorphism (e.g., pArg885His). In some embodiments, methods of the present disclosure include treating subjects with PNH, wherein residual C5 activity remains after prior or current treatment with eculizumab, by administering R5000 and/or active metabolites or variants thereof. 
     Inflammatory Indications 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat subjects with diseases, disorders and/or conditions related to inflammation. Inflammation may be upregulated during the proteolytic cascade of the complement system. Although inflammation may have beneficial effects, excess inflammation may lead to a variety of pathologies (Markiewski et al. 2007. Am J Pathol. 17: 715-27). Accordingly, compounds and compositions of the present invention may be used to reduce or eliminate inflammation associated with complement activation. 
     Sterile Inflammation 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the present invention may be used to treat, prevent or delay development of sterile inflammation. Sterile inflammation is inflammation that occurs in response to stimuli other than infection. Sterile inflammation may be a common response to stress such as genomic stress, hypoxic stress, nutrient stress or endoplasmic reticulum stress caused by a physical, chemical, or metabolic noxious stimuli. Sterile inflammation may contribute to pathogenesis of many diseases such as, but not limited to, ischemia-induced injuries, rheumatoid arthritis, acute lung injuries, drug-induced liver injuries, inflammatory bowel diseases and/or other diseases, disorders or conditions. Mechanism of sterile inflammation and methods and compositions for treatment, prevention and/or delaying of symptoms of sterile inflammation may include any of those taught by Rubartelli et al. in Frontiers in Immunology, 2013, 4:398-99, Rock et al. in Annu Rev Immunol. 2010, 28:321-342 or in U.S. Pat. No. 8,101,586, the contents of each of which are herein incorporated by reference in their entirety. 
     Systemic Inflammatory Response (SIRS) and Sepsis 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or prevent systemic inflammatory response syndrome (SIRS). SIRS is inflammation affecting the whole body. Where SIRS is caused by an infection, it is referred to as sepsis. SIRS may also be caused by non-infectious events such as trauma, injury, burns, ischemia, hemorrhage and/or other conditions. Among negative outcomes associated with SIRS and/or sepsis is multi-organ failure (MOF). Complement inhibition at the C3 level in Gram-negative sepsis significantly protects the organs against  E. coli -induced progressive MOF, but also hinders bacterial clearance. Compounds and compositions described herein include C5 complement component inhibitors that may be administered to subjects with sepsis to provide the benefits of organ protection without detrimentally altering bacterial clearance. 
     In some embodiments, the present disclosure provides methods of treating sepsis. Sepsis may be induced by microbial infection. The microbial infection may include at least one Gram-negative infectious agent. As used herein, the term “infectious agent” refers to any entity that invades or otherwise infects a cell, tissue, organ, compartment, or fluid of a sample or subject. In some cases, infectious agents may be bacteria, viruses, or other pathogens. Gram negative infectious agents are Gram-negative bacteria. Gram-negative infectious agents may include, but are not limited to  E. coli.    
     Methods of treating sepsis may include the administration of one or more C5 inhibitors to a subject. The C5 inhibitor may be R5000. According to some methods, complement activation may be reduced or prevented. Reduction or prevention of complement activity may be determined by detecting one or more products of complement activity in a subject sample. Such products may include C5 cleavage products (e.g., C5a and C5b) or downstream complexes formed as a result of C5 cleavage (e.g., C5b-9). In some embodiments, the present disclosure provides methods of treating sepsis with R5000, wherein levels of C5a and/or C5b-9 are reduced or eliminated in the subject and/or in at least one sample obtained from the subject. For example, C5a and/or C5b-9 levels may be reduced in subjects administered R5000 (or in samples obtained from such subjects) by from about 0% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects (or subject samples) not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to the same subject (or subject samples) during a pre-treatment period or an earlier period of treatment. 
     In some embodiments, C5b-9 levels reduced by R5000 treatment are C5b-9 levels associated with one or more of the classical pathway of complement activation, the alternative pathway of complement activation, and the lectin pathway of complement activation. 
     In some embodiments, the presence, absence, and/or levels of one or more factors associated with sepsis may be modulated by administering R5000 to a subject with sepsis. The presence or absence of such factors may be determined using assays for their detection. Changes in factor levels may be determined by determining the level of such factors in a subject with sepsis after R5000 treatment and comparing those levels to earlier levels in the same subject (either before R5000 treatment or during one or more earlier periods of treatment) or to levels in subjects that are not treated with R5000 (including subjects with sepsis that receive no treatment or subjects that receive some other form of treatment). Comparisons may be presented by percentage differences in factor levels between R5000 treated subjects and subjects not treated with R5000. 
     C5 cleavage product may include any proteins or complexes that may result from C5 cleavage. In some cases, C5 cleavage products may include, but are not limited to, C5a and C5b. C5b cleavage product may go on to form a complex with complement proteins C6, C7, C8, and C9 (referred to herein as “C5b-9”). Accordingly, C5 cleavage products that include C5b-9 may be detected and/or quantitated to determine whether complement activity has been reduced or prevented. Detection of C5b-9 deposition may be carried out, for example, through the use of the WIESLAB® ELISA (Euro Diagnostica, Malmo, Sweden) kit. Quantitation of cleavage products may be measured in “complement arbitrary units” (CAU) as described by others (e.g., see Bergseth G et al., 2013. Mol Immunol. 56:232-9, the contents of which are herein incorporated by reference in their entirety). 
     In some embodiments, treating sepsis with a C5 inhibitor (e.g., R5000) may reduce or prevent C5b-9 production. 
     According to the present invention, administration of R5000 to a subject may result in modulation of bacterial clearance in the subject and/or in at least one sample obtained from the subject. Bacterial clearance, as referred to herein, is the partial or complete removal/reduction of bacteria from a subject or sample. Clearance may occur by way of killing or otherwise rendering bacteria incapable of growth and/or reproduction. In some cases, bacterial clearance may occur through bacterial lysis and/or immune destruction (e.g., through phagocytosis, bacterial cell lysis, opsonization, etc.). According to some methods, bacterial clearance in subjects treated with C5 inhibitors (e.g., R5000) may have no effect or a beneficial effect on bacterial clearance. This may occur due to the absence of or a decreased effect on C3b levels with C5 inhibition. In some embodiments, methods of treating sepsis with R5000 may avoid interference with C3b-dependent opsonization or enhance C3b-dependent opsonization. 
     In some cases, bacterial clearance with R5000 treatment may be enhanced in comparison to bacterial clearance in an untreated subject or in a subject treated with another form of complement inhibitor, for example, a C3 inhibitor. In some embodiments, subjects with sepsis that are treated with R5000 may experience 0% to at least 100% enhanced bacterial clearance when compared to bacterial clearance in subjects not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to earlier bacterial clearance levels in the same subject before treatment with R5000 or during an earlier treatment period with R5000. For example, bacterial clearance in subjects treated with R5000 and/or in at least one sample obtained from such subjects may be enhanced by from about 0% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects not treated with R5000 (including subjects treated with other complement inhibitors) and/or when compared to samples obtained from such subjects or when compared to the same subject during a pre-treatment period or an earlier period of treatment and/or when compared to samples obtained from the same subject during a pre-treatment period or an earlier period of treatment. 
     Bacterial clearance may be measured in a subject by directly measuring bacterial levels in the subject and/or a subject sample or by measuring one or more indicators of bacterial clearance (e.g., levels of bacterial components released after bacterial lysis). Bacterial clearance levels may then be determined by comparison to a previous measurement of bacterial/indicator levels or to bacterial/indicator levels in a subject receiving no treatment or a different treatment. In some cases, colony forming units (cfu) from collected blood (e.g., to generate cfu/ml of blood) are examined to determine bacterial levels. 
     In some embodiments, sepsis treatment with R5000 may be carried out with no effect on phagocytosis or without substantial impairment of phagocytosis. This may include neutrophil-dependent and/or monocyte-dependent phagocytosis. Unimpaired or substantially unimpaired phagocytosis with R5000 treatment may be due to limited or non-existent changes to C3b levels with R5000 treatment. 
     Oxidative burst is a C5a-dependent process, characterized by the production of peroxide by certain cells, particularly macrophages and neutrophils, following challenge by a pathogen (see Mollnes T. E. et al., 2002. Blood 100, 1869-1877, the contents of which are herein incorporated by reference in their entirety). 
     In some embodiments, oxidative burst may be reduced or prevented in subjects with sepsis after treatment with R5000. This may be due to a decrease in C5a levels with R5000-dependent C5 inhibition. Oxidative burst may be reduced in subjects administered R5000 by from about 0% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to the same subject during a pre-treatment period or an earlier period of treatment. 
     Lipopolysaccharide (LPS) is a component of bacterial cell coats that is a known immune stimulator. Complement-dependent bacteriolysis can lead to release of LPS, contributing to inflammatory responses, such as those characteristic of sepsis. In some embodiments, treatment of sepsis with R5000 may reduce LPS levels. This may be due to a decrease in complement-mediated bacteriolysis with inhibition of C5-dependent complement activity. In some embodiments, LPS levels may be reduced or eliminated in subjects administered R5000 (or in samples obtained from such subjects) by from about 0% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects (or subject samples) not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to the same subject (or subject samples) during a pre-treatment period or an earlier period of treatment. 
     In some embodiments, LPS levels may be reduced by 100% in subjects (or subject samples) with sepsis that are treated with R5000 as compared to subjects (or subject samples) with sepsis that are not treated with R5000 (including subjects receiving one or more other forms of treatment) or when compared to the same subject (or subject sample) during a pre-treatment period or an earlier period of treatment. 
     In some embodiments of the present disclosure, sepsis-induced levels of one or more cytokine may be reduced with R5000 treatment. Cytokines include a number of cell signaling molecules that stimulate immune responses to infection. “Cytokine storm” is a dramatic upregulation of at least four cytokines, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor alpha (TNFα), that may result from bacterial infection and contribute to sepsis. C5a is known to induce the synthesis and activity of these cytokines. Inhibitors of C5, may therefore reduce cytokine levels by reducing levels of C5a. Cytokine levels may be evaluated in subjects or subject samples to evaluate the ability of C5 inhibitors to reduce the levels of one or more inflammatory cytokines upregulated during sepsis. IL-6, IL-8, MCP-1 and/or TNFα levels may be decreased in subjects administered R5000 by from about 0% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to the same subject during a pre-treatment period or an earlier period of treatment. In some embodiments, IL-6, IL-8, MCP-1, and/or TNFα levels may be reduced by 100% in subjects with sepsis that are treated with R5000 as compared to subjects with sepsis that are not treated with R5000 (including subjects receiving one or more other forms of treatment) or when compared to the same subject during a pre-treatment period or an earlier period of treatment. 101.291 One complication associated with sepsis is dysregulation of coagulation and/or fibrinolysis pathways (Levi M., et al, 2013. Seminars in thrombosis and hemostasis 39, 559-66; Rittirsch D., et al., 2008. Nature Reviews Immunology 8, 776-87; and Dempfle C., 2004. A Thromb Haemost. 91(2):213-24, the contents of each of which are herein incorporated by reference in their entirety). While controlled local activation of these pathways is important for defending against pathogens, systemic, uncontrolled activation may be harmful. Complement activity associated with bacterial infection may promote coagulation and/or fibrinolysis dysregulation due to increased host cell and tissue damage associated with MAC formation. In some embodiments, treatment of sepsis with R5000 may normalize coagulation and/or fibrinolysis pathways. 
     Dysregulation of coagulation and/or fibrinolysis associated with sepsis may include disseminated intravascular coagulation (DIC). DIC is a condition that results in tissue and organ damage due to activation of coagulation and blood clot formation in small blood vessels. This activity reduces blood flow to tissues and organs and consumes blood factors necessary for coagulation in the rest of the body. The absence of these blood factors in the blood stream may lead to uncontrolled bleeding in other parts of the body. In some embodiments, treatment of sepsis with R5000 may reduce or eliminate DIC. 
     Coagulation dysfunction associated with sepsis may be detected by measuring the activated partial thromboplastin time (APTT) and/or prothrombin time (PT). These are tests performed on plasma samples to determine whether coagulation factor levels are low. In subjects with DIC, APTT and/or PT are prolonged due to reduced levels of coagulation factors. In some embodiments, subject treatment of sepsis with R5000 may lower and/or normalize APTT and/or PT in samples obtained from treated subjects. 
     Coagulation dysfunction associated with sepsis may further be evaluated through analysis of thrombin-antithrombin (TAT) complex levels and/or leukocyte expression of Tissue Factor (TF) mRNA. Increased levels of TAT complex and leukocyte expression of TF mRNA are associated with coagulation dysfunction and are consistent with DIC. In some embodiments, treatment of sepsis with R5000 may result in a reduction in TAT levels and/or leukocyte TF mRNA levels of from about 0.005% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to the same subject during a pre-treatment period or an earlier period of treatment. In some embodiments, TAT levels and/or leukocyte TF mRNA levels may be reduced by 100% in subjects with sepsis that are treated with R5000 as compared to subjects with sepsis that are not treated with R5000 (including subjects receiving one or more other forms of treatment) or when compared to the same subject during a pre-treatment period or an earlier period of treatment. 
     Factor XII is a factor important for normal coagulation in plasma. Factor XII levels may be decreased in plasma samples taken from subjects with coagulation dysfunction (e.g., DIC) due to consumption of Factor XII associated with coagulation in small blood vessels. In some embodiments, sepsis treatment with R5000 may reduce Factor XII consumption. Accordingly, Factor XII levels may be increased in plasma samples taken from subjects with sepsis after R5000 treatment. Factor XII levels may be increased in plasma samples by from about 0.005% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to subjects not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to plasma samples taken from the same subject during a pre-treatment period or an earlier period of treatment. In some embodiments, Factor XII levels may be increased by 100% in plasma samples from subjects with sepsis that are treated with R5000 as compared to plasma samples from subjects with sepsis that are not treated with R5000 (including subjects receiving one or more other forms of treatment) or when compared to plasma samples taken from the same subject during a pre-treatment period or an earlier period of treatment. 
     Fibrinolysis is the breakdown of fibrin due to enzymatic activity, a process critical for clot formation. Fibrinolysis dysregulation may occur in severe sepsis and is reported to affect normal clotting in baboons challenged with  E. coli  (P. de Boer J. P., et al., 1993. Circulatory shock. 39, 59-67, the contents of which are herein incorporated by reference in their entirety). Plasma indicators of sepsis-dependent fibrinolysis dysfunction (including, but not limited to fibrinolysis dysfunction associated with DIC) may include, but are not limited to decreased fibrinogen levels (indicating a reduced ability to form fibrin clots), increased tissue plasminogen activator (tPA) levels, increased plasminogen activator inhibitor type 1 (PAI-1) levels, increased plasmin-antiplasmin (PAP) levels, increased fibrinogen/fibrin degradation products, and increased D-dimer levels. In some embodiments, treatment of sepsis with R5000 may result in a decrease in plasma fibrinogen levels and/or an increase in plasma levels of tPA, PAI-1, PAP, fibrinogen/fibrin degradation product, and/or D-dimer of from about 0.005% to about 0.05%, from about 0.01% to about 1%, from about 0.05% to about 2%, from about 0.1% to about 5%, from about 0.5% to about 10%, from about 1% to about 15%, from about 5% to about 25%, from about 10% to about 50%, from about 20% to about 60%, from about 25% to about 75%, from about 50% to about 100% when compared to levels in plasma samples from subjects not treated with R5000 (including subjects treated with other complement inhibitors) or when compared to levels in plasma samples taken from the same subject during a pre-treatment period or an earlier period of treatment. In some embodiments, sepsis-associated decrease in plasma fibrinogen levels and/or a sepsis-associated increase in plasma levels of tPA, PAI-1, PAP, fibrinogen/fibrin degradation product, and/or D-dimer may differ by at least 10,000% when compared to levels in plasma samples from subjects with sepsis that are treated with R5000. 
     Another consequence of overactive complement activity associated with sepsis is a reduction in red blood cells due to complement-dependent hemolysis and/or C3b-dependent opsonization. Methods of treating sepsis with R5000 according to the present disclosure may include reducing complement-dependent hemolysis. One method of evaluating complement-dependent hemolysis associated with sepsis involves obtaining a complete blood cell count. Complete blood cell counts may be obtained through automated processes that count the cell types present in blood samples. Results from complete blood cell count analysis typically include levels of hematocrit, red blood cell (RBC) counts, white blood cell (WBC) counts, and platelets. Hematocrit levels are used to determine the percentage of blood (by volume) that is made up of red blood cells. Hematocrit levels, platelet levels, RBC levels, and WBC levels may be reduced in sepsis due to hemolysis. In some embodiments, treatment of sepsis with R5000 increases hematocrit levels, platelet levels, RBC levels, and/or WBC levels. Increases may be immediate or may occur over time with treatment (e.g., single or multiple dose treatments). 
     In some embodiments, subject treatment with R5000 may decrease leukocyte (e.g., neutrophils and macrophages) activation associated with sepsis. “Activation,” as used herein in the context of leukocytes refers to mobilization and/or maturation of these cells to carryout associated immune functions. Decreased leukocyte activation with R5000 treatment may be determined by assessing the subject treated or a sample obtained from the subject treated. 
     In some embodiments, treatment of sepsis with R5000 may improve one or more vital signs in subjects being treated. Such vital signs may include, but are not limited to, heart rate, mean systemic arterial pressure (MSAP), respiration rate, oxygen saturation, and body temperature. 
     In some embodiments, treatment of sepsis with R5000 may stabilize or reduce capillary leak and/or endothelial barrier dysfunction associated with sepsis (i.e., to maintain or improve capillary leak and/or endothelial barrier dysfunction). Stabilization or reduction of capillary leak and/or endothelial barrier dysfunction may be determined by measuring total plasma protein levels and/or plasma albumin levels. An increase in either level in comparison to plasma levels associated with sepsis may indicate reduced capillary leak. Accordingly, treatment of sepsis with R5000 may increase levels of total plasma protein and/or plasma albumin. 
     Methods of the present disclosure may include methods of treating sepsis with R5000, wherein levels of one or more acute phase proteins are reduced. Acute phase proteins are proteins produced by the liver under inflammatory condition. R5000 treatment may reduce inflammation associated with sepsis and lead to decreased production of acute phase proteins by the liver. 
     According to some methods of the invention, sepsis-induced organ damage and/or organ dysfunction may be reduced, reversed, or prevented by treatment with R5000. Indicators that may be reduced with improved organ function may include, but are not limited to plasma lactate (demonstrating improved vascular perfusion and clearance), creatinine, blood urea nitrogen (both indicating improved kidney function), and liver transaminases (indicating improved liver function). In some embodiments, febrile response, risk of secondary infection and/or risk of sepsis reoccurrence is reduced in subjects treated for sepsis with R5000. 
     Methods of the present disclosure may include preventing sepsis-related death and/or improving survival time of subjects afflicted with sepsis through treatment with R5000. Improved survival time may be determined through comparison of survival time in R5000-treated subjects to survival time in un-treated subjects (including subjects treated with one or more other forms of treatment). In some embodiments, survival times are increased by at least 1 day, at least 2 days, at least 3 days, at least 4 days, at least 5 days, at least 6 days, at least 7 days, at least 2 weeks, at least 1 month, at least 2 months, at least 4 months, at least 6 months, at least 1 year, at least 2 years, at least 5 years, or at least 10 years. 
     In some embodiments, administration of R5000 is carried out in a single dose. In some embodiments, administration of R5000 is carried out in multiple doses. For example, R5000 administration may include administration of an initial dose, followed by one or more repeat doses. Repeat doses may be administered from about 1 hour to about 24 hours, from about 2 hours to about 48 hours, from about 4 hours to about 72 hours, from about 8 hours to about 96 hours, from about 12 hours to about 36 hours, or from about 18 hours to about 60 hours after a previous dose. In some cases, repeat doses may be administered 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 2 weeks, 4 weeks, 2 months, 4 months, 6 months, or more than 6 months after a previous dose. In some cases, repeat doses may be administered as needed to stabilize or reduce sepsis or to stabilize or reduce one or more effects associated with sepsis in a subject. Repeat doses may include the same amount of R5000 or may include a different amount. 
     Compounds and compositions of the invention may be used to control and/or balance complement activation for prevention and treatment of SIRS, sepsis and/or MOF. The methods of applying complement inhibitors to treat SIRS and sepsis may include those in U.S. publication No. US2013/0053302 or in U.S. Pat. No. 8,329,169, the contents of each of which are herein incorporated by reference in their entirety. 
     Acute Respiratory Distress Syndrome (ARDS) 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or prevent development of acute respiratory distress syndrome (ARDS). ARDS is a widespread inflammation of the lungs and may be caused by trauma, infection (e.g., sepsis), severe pneumonia and/or inhalation of harmful substances. ARDS is typically a severe, life-threatening complication. Studies suggest that neutrophils may contribute to development of ARDS by affecting the accumulation of polymorphonuclear cells in the injured pulmonary alveoli and interstitial tissue of the lungs. Accordingly, compounds and compositions of the invention may be administered to reduce and/or prevent tissue factor production in alveolar neutrophils. Compounds and compositions of the invention may further be used for treatment, prevention and/or delaying of ARDS, in some cases according to any of the methods taught in International publication No. WO2009/014633, the contents of which are herein incorporated by reference in their entirety. 
     Periodontitis 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat or prevent development of periodontitis and/or associated conditions. Periodontitis is a widespread, chronic inflammation leading to the destruction of periodontal tissue which is the tissue supporting and surrounding the teeth. The condition also involves alveolar bone loss (bone that holds the teeth). Periodontitis may be caused by a lack of oral hygiene leading to accumulation of bacteria at the gum line, also known as dental plaque. Certain health conditions such as diabetes or malnutrition and/or habits such as smoking may increase the risk of periodontitis. Periodontitis may increase the risk of stroke, myocardial infarction, atherosclerosis, diabetes, osteoporosis, pre-term labor, as well as other health issues. Studies demonstrate a correlation between periodontitis and local complement activity. Periodontal bacteria may either inhibit or activate certain components of the complement cascade. Accordingly, compounds and compositions of the invention may be used to prevent and/or treat periodontitis and associated diseases and conditions. Complement activation inhibitors and treatment methods may include any of those taught by Hajishengallis in Biochem Pharmacol. 2010, 15; 80(12): 1 and Lambris or in US publication No. US2013/0344082, the contents of each of which are herein incorporated by reference in their entirety. 
     Dermatomyositis 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and/or methods of the invention may be used to treat dermatomyositis. Dermatomyositis is an inflammatory myopathy characterized by muscle weakness and chronic muscle inflammation. Dermatomyositis often begins with a skin rash that is associated concurrently or precedes muscle weakness. Compounds, compositions, and/or methods of the invention may be used to reduce or prevent dermatomyositis. 
     Wounds and Injuries 
     Compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or promote healing of different types of wounds and/or injuries. As used herein, the term “injury” typically refers to physical trauma, but may include localized infection or disease processes. Injuries may be characterized by harm, damage or destruction caused by external events affecting body parts and/or organs. Wounds are associated with cuts, blows, burns and/or other impacts to the skin, leaving the skin broken or damaged. Wounds and injuries are often acute but if not healed properly they may lead to chronic complications and/or inflammation. 
     Wounds and Burn Wounds 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or to promote healing of wounds. Healthy skin provides a waterproof, protective barrier against pathogens and other environmental effectors. The skin also controls body temperature and fluid evaporation. When skin is wounded these functions are disrupted making skin healing challenging. Wounding initiates a set of physiological processes related to the immune system that repair and regenerate tissue. Complement activation is one of these processes. Complement activation studies have identified several complement components involved with wound healing as taught by van de Goot et al. in J Burn Care Res 2009, 30:274-280 and Cazander et al. Clin Dev Immunol, 2012, 2012:534291, the contents of each of which are herein incorporated by reference in their entirety. In some cases, complement activation may be excessive, causing cell death and enhanced inflammation (leading to impaired wound healing and chronic wounds). In some cases, compounds and compositions of the present invention may be used to reduce or eliminate such complement activation to promote wound healing. Treatment with compounds and compositions of the invention may be carried out according to any of the methods for treating wounds disclosed in International publication number WO2012/174055, the contents of which are herein incorporated by reference in their entirety. 
     Head Trauma 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or promote healing of head trauma. Head traumas include injuries to the scalp, the skull or the brain. Examples of head trauma include, but are not limited to concussions, contusions, skull fracture, traumatic brain injuries and/or other injuries. Head traumas may be minor or severe. In some cases, head trauma may lead to long term physical and/or mental complications or death. Studies indicate that head traumas may induce improper intracranial complement cascade activation, which may lead to local inflammatory responses contributing to secondary brain damage by development of brain edema and/or neuronal death (Stahel et al. in Brain Research Reviews, 1998, 27: 243-56, the contents of which are herein incorporated by reference in their entirety). Compounds and compositions of the invention may be used to treat head trauma and/or to reduce or prevent related secondary complications. Methods of using compounds and compositions of the invention to control complement cascade activation in head trauma may include any of those taught by Holers et al. in U.S. Pat. No. 8,911,733, the contents of which are herein incorporated by reference in their entirety. 
     Crush Injury 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or promote healing of crush injuries. Crush injuries are injuries caused by a force or a pressure put on the body causing bleeding, bruising, fractures, nerve injuries, wounds and/or other damages to the body. Compounds and compositions of the invention may be used to reduce complement activation following crush injuries, thereby promoting healing after crush injuries (e.g. by promoting nerve regeneration, promoting fracture healing, preventing or treating inflammation, and/or other related complications). Compounds and compositions of the invention may be used to promote healing according to any of the methods taught in U.S. Pat. No. 8,703,136; International Publication Nos. WO2012/162215; WO2012/174055; or US publication No. US2006/0270590, the contents of each of which are herein incorporated by reference in their entirety. 
     Ischemia/Reperfusion Injury 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and/or methods of the present disclosure may be used to treat injuries associated with ischemia and/or reperfusion. Such injuries may be associated with surgical intervention (e.g., transplantation). Accordingly, compounds, compositions, and/or methods of the present disclosure may be used to reduce or prevent ischemia and/or reperfusion injuries. 
     Autoimmune Disease 
     The compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat subjects with autoimmune diseases and/or disorders. The immune system may be divided into innate and adaptive systems, referring to nonspecific immediate defense mechanisms and more complex antigen-specific systems, respectively. The complement system is part of the innate immune system, recognizing and eliminating pathogens. Additionally, complement proteins may modulate adaptive immunity, connecting innate and adaptive responses. Autoimmune diseases and disorders are immune abnormalities causing the system to target self tissues and substances. Autoimmune disease may involve certain tissues or organs of the body. Compounds and compositions of the invention may be used to modulate complement in the treatment and/or prevention of autoimmune diseases. In some cases, such compounds and compositions may be used according to the methods presented in Ballanti et al. Immunol Res (2013) 56:477-491, the contents of which are herein incorporated by reference in their entirety. 
     Anti Phospholipid Syndrome (APS) and Catastrophic Anti Phospholipid Syndrome (CAPS) 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat anti-phospholipid syndrome (APS) by complement activation control. APS is an autoimmune condition caused by anti-phospholipid antibodies that cause the blood to clot. APS may lead to recurrent venous or arterial thrombosis in organs, and complications in placental circulations causing pregnancy-related complications such as miscarriage, still birth, preeclampsia, premature birth and/or other complications. Catastrophic anti-phospholipid syndrome (CAPS) is an extreme and acute version of a similar condition leading to occlusion of veins in several organs simultaneously. Studies suggest that complement activation may contribute to APS-related complications including pregnancy-related complications, thrombotic (clotting) complications, and vascular complications. Compound and compositions of the invention may be used to treat APS-related conditions by reducing or eliminating complement activation. In some cases, compounds and compositions of the invention may be used to treat APS and/or APS-related complications according to the methods taught by Salmon et al. Ann Rheum Dis 2002; 61 (Suppl 11):ii46-ii50 and Mackworth-Young in Clin Exp Immunol 2004, 136:393-401, the contents of which are herein incorporated by reference in their entirety. 
     Cold Agglutinin Disease 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat cold agglutinin disease (CAD), also referred to as cold agglutinin-mediated hemolysis. CAD is an autoimmune disease resulting from a high concentration of IgM antibodies interacting with red blood cells at low range body temperatures [Engelhardt et al. Blood, 2002, 100(5):1922-23]. CAD may lead to conditions such as anemia, fatigue, dyspnea, hemoglobinuria and/or acrocyanosis. CAD is related to robust complement activation and studies have shown that CAD may be treated with complement inhibitor therapies. Accordingly, the present invention provides methods of treating CAD using compounds and compositions of the invention. In some cases, compounds and compositions of the invention may be used to treat CAD according to the methods taught by Roth et al in Blood, 2009, 113:3885-86 or in International publication No. WO2012/139081, the contents of each of which are herein incorporated by reference in their entirety. 
     Myasthenia Gravis 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and/or methods of the invention may be used to treat Myasthenia gravis. Myasthenia gravis (MG) is a rare complement-mediated autoimmune disease characterized by the production of autoantibodies targeting proteins that are critical for the normal transmission of electrical signals from nerves to muscles. Although the prognosis of MG is generally benign, in 10% to 15% of patients disease control either cannot be achieved with current therapies, or results in severe side effects of immunosuppressive therapy. This severe form of MG is known as refractory MG (rMG), and affects approximately 9,000 individuals in the United States. 
     Patients present with muscle weakness that characteristically becomes more severe with repeated use and recovers with rest. Muscle weakness can be localized to specific muscles, such as those responsible for eye movements, but often progresses to more diffuse muscle weakness. rMG may even become life-threatening when muscle weakness involves the diaphragm and the other chest wall muscles responsible for breathing. This is the most feared complication of rMG, known as myasthenic crisis, and requires hospitalization, intubation, and mechanical ventilation. Approximately 15% to 20% of patients experience a myasthenic crisis within two years of diagnosis. 
     The most common target of autoantibodies in MG is the acetylcholine receptor, or AchR, located at the neuromuscular junction, the point at which a motor neuron transmits signals to a skeletal muscle fiber. Binding of anti-AchR autoantibodies to the muscle endplate results in activation of the classical complement cascade and deposition of MAC on the post-synaptic muscle fiber leading to local damage to the muscle membrane, and reduced responsiveness of the muscle to stimulation by the neuron. 
     Inhibition of terminal complement activity may be used to block complement-mediated damage resulting from MG and/or rMG. In some embodiments, compounds and/or compositions of the present disclosure may be used to treat MG and/or rMG. Such methods may be used to inhibit C5 activity to reduce or prevent neuromuscular issues associated with MG and/or rMG. 
     Guillain-Barre Syndrome 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and methods of the invention may be used to treat Guillain-Barre syndrome (GBS). GBS is an autoimmune disease involving autoimmune attack of the peripheral nervous system. Compounds, compositions, and/or methods of the invention may be used to reduce or prevent peripheral nervous issues associated with GBS. 
     Vascular Indications 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat vascular indications affecting blood vessels (e.g., arteries, veins, and capillaries). Such indications may affect blood circulation, blood pressure, blood flow, organ function and/or other bodily functions. 
     Thrombotic Microangiopathy (TMA) 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat and/or prevent thrombotic microangiopathy (TMA) and associated diseases. Microangiopathies affect small blood vessels (capillaries) of the body causing capillary walls to become thick, weak, and prone to bleeding and slow blood circulation. TMAs tend to lead to the development of vascular thrombi, endothelial cell damage, thrombocytopenia, and hemolysis. Organs such as the brain, kidney, muscles, gastrointestinal system, skin, and lungs may be affected. TMAs may arise from medical operations and/or conditions that include, but are not limited to, hematopoietic stem cell transplantation (HSCT), renal disorders, diabetes and/or other conditions. TMAs may be caused by underlying complement system dysfunction, as described by Meri et al. in European Journal of Internal Medicine, 2013, 24: 496-502, the contents of which are herein incorporated by reference in their entirety. Generally, TMAs may result from increased levels of certain complement components leading to thrombosis. In some cases, this may be caused by mutations in complement proteins or related enzymes. Resulting complement dysfunction may lead to complement targeting of endothelial cells and platelets leading to increased thrombosis. In some embodiments, TMAs may be prevented and/or treated with compounds and compositions of the invention. In some cases, methods of treating TMAs with compounds and compositions of the invention may be carried out according to those described in US publication Nos. US2012/0225056 or US2013/0246083, the contents of each of which are herein incorporated by reference in their entirety. 
     Disseminated Intravascular Coagulation (DIC) 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat disseminated intravascular coagulation (DIC) by controlling complement activation. DIC is a pathological condition where the clotting cascade in blood is widely activated and results in formation of blood clots especially in the capillaries. DIC may lead to an obstructed blood flow of tissues and may eventually damage organs. Additionally, DIC affects the normal process of blood clotting that may lead to severe bleeding. Compounds and compositions of the invention may be used to treat, prevent or reduce the severity of DIC by modulating complement activity. In some cases compounds and compositions of the invention may be used according to any of the methods of DIC treatment taught in U.S. Pat. No. 8,652,477, the contents of which are herein incorporated by reference in their entirety. 
     Vasculitis 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat vasculitis. Generally, vasculitis is a disorder related to inflammation of blood vessels, including veins and arteries, characterized by white blood cells attacking tissues and causing swelling of the blood vessels. Vasculitis may be associated with an infection, such as in Rocky Mountain spotted fever, or autoimmunity. An example of autoimmunity associated vasculitis is Anti-Neutrophil Cytoplasmic Autoantibody (ANCA) vasculitis. ANCA vasculitis is caused by abnormal antibodies attacking the body&#39;s own cells and tissues. ANCAs attack the cytoplasm of certain white blood cells and neutrophils, causing them to attack the walls of the vessels in certain organs and tissues of the body. ANCA vasculitis may affect skin, lungs, eyes and/or kidney. Studies suggest that ANCA disease activates an alternative complement pathway and generates certain complement components that create an inflammation amplification loop resulting in a vascular injury (Jennette et al. 2013, Semin Nephrol. 33(6): 557-64, the contents of which are herein incorporated by reference in their entirety). In some cases, compounds and compositions of the invention may be used to prevent and/or treat ANCA vasculitis by inhibiting complement activation. 
     Atypical Hemolytic Uremic Syndrome 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and/or methods of the present disclosure may be useful for treatment of atypical hemolytic uremic syndrome (aHUS). aHUS is a rare disease caused by unchecked complement activation characterized by blood clot formation in small blood vessels. Compositions and methods of the invention may be useful for reducing or preventing complement activation associated with aHUS. 
     Neurological Indications 
     The compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent, treat and/or ease the symptoms of neurological indications, including, but not limited to neurodegenerative diseases and related disorders. Neurodegeneration generally relates to a loss of structure or function of neurons, including death of neurons. These disorders may be treated by inhibiting the effect of complement on neuronal cells using compounds and compositions of the invention. Neurodegenerative related disorders include, but are not limited to, Amyelotrophic Lateral Sclerosis (ALS), Multiple Sclerosis (MS), Parkinson&#39;s disease and Alzheimer&#39;s disease. 
     Amyotrophic Lateral Sclerosis (ALS) 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent, treat and/or ease the symptoms of ALS. ALS is a fatal motor neuron disease characterized by the degeneration of spinal cord neurons, brainstems and motor cortex. ALS causes loss of muscle strength leading eventually to a respiratory failure. Complement dysfunction may contribute to ALS, and therefore ALS may be prevented, treated and/or the symptoms may be reduced by therapy with compounds and compositions of the invention targeting complement activity. In some cases, compounds and compositions of the invention may be used to promote nerve regeneration. In some cases, compounds and compositions of the invention may be used as complement inhibitors according to any of the methods taught in US publication No. US2014/0234275 or US2010/0143344, the contents of each of which are herein incorporated by reference in their entirety. 
     Alzheimer&#39;s Disease 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat Alzheimer&#39;s disease by controlling complement activity. Alzheimer&#39;s disease is a chronic neurodegenerative disease with symptoms that may include disorientation, memory loss, mood swings, behavioral problems and eventually loss of bodily functions. Alzheimer&#39;s disease is thought to be caused by extracellular brain deposits of amyloid that are associated with inflammation-related proteins such as complement proteins (Sjoberg et al. 2009. Trends in Immunology. 30(2): 83-90, the contents of which are herein incorporated by reference in their entirety). In some cases, compounds and compositions of the invention may be used as complement inhibitors according to any of the Alzheimer&#39;s treatment methods taught in US publication No. US2014/0234275, the contents of which are herein incorporated by reference in their entirety. 
     Kidney-Related Indications 
     The compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to treat certain diseases, disorders and/or conditions related to kidneys, in some cases by inhibiting complement activity. Kidneys are organs responsible for removing metabolic waste products from the blood stream. Kidneys regulate blood pressure, the urinary system, and homeostatic functions and are therefore essential for a variety of bodily functions. Kidneys may be more seriously affected by inflammation (as compared to other organs) due to unique structural features and exposure to blood. Kidneys also produce their own complement proteins which may be activated upon infection, kidney disease, and renal transplantations. In some cases, compounds and compositions of the invention may be used as complement inhibitors in the treatment of certain diseases, conditions, and/or disorders of the kidney according to the methods taught by Quigg, J Immunol 2003; 171:3319-24, the contents of which are herein incorporated by reference in their entirety. 
     Lupus Nephritis 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat lupus nephritis by inhibiting complement activity. Lupus nephritis is a kidney inflammation caused by an autoimmune disease called systemic lupus erythematosus (SLE). Symptoms of lupus nephritis include high blood pressure; foamy urine; swelling of the legs, the feet, the hands, or the face; joint pain; muscle pain; fever; and rash. Lupus nephritis may be treated by inhibitors that control complement activity, including compounds and compositions of the present invention. Methods and compositions for preventing and/or treating Lupus nephritis by complement inhibition may include any of those taught in US publication No. US2013/0345257 or U.S. Pat. No. 8,377,437, the contents of each of which are herein incorporated by reference in their entirety. In some embodiments, compounds and/or compositions of the present disclosure may be used to prevent and/or treat lupus nephritis by binding C5 and preventing the progression of kidney disease in lupus nephritis. The binding to C5 may prevent and/or treat lupus nephritis by preventing C5 activity and blocking complement mediated damage to the kidney cells. 
     Membranous Glomerulonephritis (MGN) 
     In some embodiments, compounds and composition, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat membranous glomerulonephritis (MGN) disorder by inhibiting the activation of certain complement components. MGN is a disorder of the kidney that may lead to inflammation and structural changes. MGN is caused by antibodies binding to a soluble antigen in kidney capillaries (glomerulus). MGN may affect kidney functions, such as filtering fluids and may lead to kidney failure. Compounds and compositions of the invention may be used according to methods of preventing and/or treating MGN by complement inhibition taught in U.S. publication No. US2010/0015139 or in International publication No. WO2000/021559, the contents of each of which are herein incorporated by reference in their entirety. 
     Hemodialysis Complications 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat complications associated with hemodialysis by inhibiting complement activation. Hemodialysis is a medical procedure used to maintain kidney function in subjects with kidney failure. In hemodialysis, the removal of waste products such as creatinine, urea, and free water from blood is performed externally. A common complication of hemodialysis treatment is chronic inflammation caused by contact between blood and the dialysis membrane. Another common complication is thrombosis referring to a formation of blood clots that obstructs the blood circulation. Studies have suggested that these complications are related to complement activation. Hemodialysis may be combined with complement inhibitor therapy to provide means of controlling inflammatory responses and pathologies and/or preventing or treating thrombosis in subjects going through hemodialysis due to kidney failure. Methods of using compounds and compositions of the invention for treatment of hemodialysis complications may be carried out according to any of the methods taught by DeAngelis et al in Immunobiology, 2012, 217(11): 1097-1105 or by Kourtzelis et al. Blood, 2010, 116(4):631-639, the contents of each of which are herein incorporated by reference in their entirety. 
     Ocular Diseases 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat certain ocular related diseases, disorders and/or conditions. In a healthy eye the complement system is activated at a low level and is continuously regulated by membrane-bound and soluble intraocular proteins that protect against pathogens. Therefore the activation of complement plays an important role in several complications related to the eye and controlling complement activation may be used to treat such diseases. Compounds and compositions of the invention may be used as complement inhibitors in the treatment of ocular disease according to any of the methods taught by Jha et al. in Mol Immunol. 2007; 44(16): 3901-3908 or in U.S. Pat. No. 8,753,625, the contents of each of which are herein incorporated by reference in their entirety. 
     Age-Related Macular Degeneration (AMD) 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat age-related macular degeneration (AMD) by inhibiting ocular complement activation. AMD is a chronic ocular disease causing blurred central vision, blind spots in central vision, and/or eventual loss of central vision. Central vision affects ability to read, drive a vehicle and/or recognize faces. AMD is generally divided into two types, non-exudative (dry) and exudative (wet). Dry AMD refers to the deterioration of the macula which is the tissue in the center of the retina. Wet AMD refers to the failure of blood vessels under the retina leading to leaking of blood and fluid. Several human and animal studies have identified complement proteins that are related to AMD and novel therapeutic strategies included controlling complement activation pathways, as discussed by Jha et al. in Mol Immunol. 2007; 44(16): 3901-8. Methods of the invention involving the use of compounds and compositions of the invention for prevention and/or treatment of AMD may include any of those taught in US publication Nos. US2011/0269807 or US2008/0269318, the contents of each of which are herein incorporated by reference in their entirety. 
     Corneal Disease 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat corneal diseases by inhibiting ocular complement activation. The complement system plays an important role in protection of the cornea from pathogenic particles and/or inflammatory antigens. The cornea is the outermost front part of the eye covering and protecting the iris, pupil and anterior chamber and is therefore exposed to external factors. Corneal diseases include, but are not limited to, keratoconus, keratitis, ocular herpes and/or other diseases. Corneal complications may cause pain, blurred vision, tearing, redness, light sensitivity and/or corneal scarring. The complement system is critical for corneal protection, but complement activation may cause damage to the corneal tissue after an infection is cleared as certain complement compounds are heavily expressed. Methods of the present invention for modulating complement activity in the treatment of corneal disease may include any of those taught by Jha et al. in Mol Immunol. 2007; 44(16): 3901-8, the contents of which are herein incorporated by reference in their entirety. 
     Autoimmune Uveitis 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat uveitis, which is an inflammation of the uveal layer of the eye. Uvea is the pigmented area of the eye comprising the choroids, iris and ciliary body of the eye. Uveitis causes redness, blurred vision, pain, synechia and may eventually cause blindness. Studies have indicated that complement activation products are present in the eyes of patients with autoimmune uveitis and complement plays an important role in disease development. In some cases, compounds and compositions of the invention may be used to treat and/or prevent uveitis according to any of the methods identified in Jha et al. in Mol Immunol. 2007. 44(16): 3901-8, the contents of which are herein incorporated by reference in their entirety. 
     Diabetic Retinopathy 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat diabetic retinopathy which is a disease caused by changes in retinal blood vessels in diabetic patients. Retinopathy may cause blood vessel swelling and fluid leaking and/or growth of abnormal blood vessels. Diabetic retinopathy affects vision and may eventually lead to blindness. Studies have suggested that activation of complement has an important role in the development of diabetic retinopathy. In some cases, compounds and compositions of the invention may be used according to methods of diabetic retinopathy treatment described in Jha et al. Mol Immunol. 2007; 44(16): 3901-8, the contents of which are herein incorporated by reference in their entirety. 
     Neuromyelitis Optica (NMO) 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and/or methods of the invention may be used to treat neuromyelitis optica (NMO). NMO is an autoimmune disease that leads to destruction of the optic nerve. Compounds and/or methods of the invention may be used to prevent nerve destruction in subjects with NMO. 
     Sjogren&#39;s Syndrome 
     In some embodiments, compounds, compositions, e.g., pharmaceutical compositions, and/or methods of the invention may be used to treat Sjorgren&#39;s syndrome. Sjorgren&#39;s syndrome is an ocular disease characterized by dry eyes that may burn and/or itch. It is an autoimmune disorder where the immune system targets glands in the eyes and mouth responsible for moisturizing those regions. Compounds, compositions, and/or methods of the present disclosure may be used to treat and/or reduce the symptoms of Sjorgren&#39;s syndrome. 
     Pre-Eclampsia and HELLP-Syndrome 
     In some embodiments, compounds and compositions, e.g., pharmaceutical compositions, of the invention may be used to prevent and/or treat pre-eclampsia and/or HELLP (abbreviation standing for syndrome features of 1) hemolysis, 2) elevated liver enzymes and 3) low platelet count) syndrome by complement inhibitor therapy. Pre-eclampsia is a disorder of pregnancy with symptoms including elevated blood pressure, swelling, shortness of breath, kidney dysfunction, impaired liver function and/or low blood platelet count. Pre-eclampsia is typically diagnosed by a high urine protein level and high blood pressure. HELLP syndrome is a combination of hemolysis, elevated liver enzymes and low platelet conditions. Hemolysis is a disease involving rupturing of red blood cells leading to the release of hemoglobin from red blood cells. Elevated liver enzymes may indicate a pregnancy-induced liver condition. Low platelet levels lead to reduced clotting capability, causing danger of excessive bleeding. HELLP is associated with a pre-eclampsia and liver disorder. HELLP syndrome typically occurs during the later stages of pregnancy or after childbirth. It is typically diagnosed by blood tests indicating the presence of the three conditions it involves. Typically HELLP is treated by inducing delivery. 
     Studies suggest that complement activation occurs during HELLP syndrome and pre-eclampsia and that certain complement components are present at increased levels during HELLP and pre-eclampsia. Complement inhibitors may be used as therapeutic agents to prevent and/or treat these conditions. Compounds and compositions of the invention may be used according to methods of preventing and/or treating HELLP and pre-eclampsia taught by Heager et al. in Obstetrics &amp; Gynecology, 1992, 79(1):19-26 or in International publication No. WO201/078622, the contents of each of which are herein incorporated by reference in their entirety. 
     Formulations 
     In some embodiments, compounds or compositions, e.g., pharmaceutical compositions, of the invention are formulated in aqueous solutions. In some cases, aqueous solutions further include one or more salt and/or one or more buffering agent. Salts may include sodium chloride which may be included at concentrations of from about 0.05 mM to about 50 mM, from about 1 mM to about 100 mM, from about 20 mM to about 200 mM, or from about 50 mM to about 500 mM. Further solutions may comprise at least 500 mM sodium chloride. In some cases, aqueous solutions include sodium phosphate. Sodium phosphate may be included in aqueous solutions at a concentration of from about 0.005 mM to about 5 mM, from about 0.01 mM to about 10 mM, from about 0.1 mM to about 50 mM, from about 1 mM to about 100 mM, from about 5 mM to about 150 mM, or from about 10 mM to about 250 mM. In some cases, at least 250 mM sodium phosphate concentrations are used. 
     Compositions of the invention may include C5 inhibitors at a concentration of from about 0.001 mg/mL to about 0.2 mg/mL, from about 0.01 mg/mL to about 2 mg/mL, from about 0.1 mg/mL to about 10 mg/mL, from about 0.5 mg/mL to about 5 mg/mL, from about 1 mg/mL to about 20 mg/mL, from about 15 mg/mL to about 40 mg/mL, from about 25 mg/mL to about 75 mg/mL, from about 50 mg/mL to about 200 mg/mL, or from about 100 mg/mL to about 400 mg/mL. In some cases, compositions of the invention include C5 inhibitors at a concentration of at least 400 mg/mL. 
     Compositions of the invention may comprise C5 inhibitors at a concentration of approximately, about or exactly any of the following values: 0.001 mg/mL, 0.2 mg/mL, 0.01 mg/mL, 2 mg/mL, 0.1 mg/mL, 10 mg/mL, 0.5 mg/mL, 5 mg/mL, 1 mg/mL, 20 mg/mL, 15 mg/mL, 40 mg/mL, 25 mg/mL, 75 mg/mL, 50 mg/mL, 200 mg/mL, 100 mg/mL, or 400 mg/mL. In some cases, compositions of the invention include C5 inhibitors at a concentration of at least 40 mg/mL. 
     In some embodiments, compositions of the invention include aqueous compositions including at least water and a C5 inhibitor (e.g., a cyclic C5 inhibitor polypeptide). Aqueous C5 inhibitor compositions of the invention may further include one or more salt and/or one or more buffering agent. In some cases, aqueous compositions of the invention include water, a cyclic C5 inhibitor polypeptide, a salt, and a buffering agent. 
     Aqueous C5 inhibitor formulations of the invention may have pH levels of from about 2.0 to about 3.0, from about 2.5 to about 3.5, from about 3.0 to about 4.0, from about 3.5 to about 4.5, from about 4.0 to about 5.0, from about 4.5 to about 5.5, from about 5.0 to about 6.0, from about 5.5 to about 6.5, from about 6.0 to about 7.0, from about 6.5 to about 7.5, from about 7.0 to about 8.0, from about 7.5 to about 8.5, from about 8.0 to about 9.0, from about 8.5 to about 9.5, or from about 9.0 to about 10.0. 
     In some cases, compounds and compositions of the invention are prepared according to good manufacturing practice (GMP) and/or current GMP (cGMP). Guidelines used for implementing GMP and/or cGMP may be obtained from one or more of the US Food and Drug Administration (FDA), the World Health Organization (WHO), and the International Conference on Harmonization (ICH). 
     Dosage and Administration 
     For treatment of human subjects, C5 inhibitors (e.g., R5000 and/or active metabolites or variants thereof) may be formulated as pharmaceutical compositions. Depending on the subject to be treated, the mode of administration, and the type of treatment desired (e.g., prevention, prophylaxis, or therapy) C5 inhibitors may be formulated in ways consonant with these parameters. A summary of such techniques is found in Remington: The Science and Practice of Pharmacy, 21st Edition, Lippincott Williams &amp; Wilkins, (2005); and Encyclopedia of Pharmaceutical Technology, eds. J. Swarbrick and J. C. Boylan, 1988-1999, Marcel Dekker, New York, each of which is incorporated herein by reference. 
     C5 inhibitors of the present invention (e.g., R5000 and/or active metabolites or variants thereof) may be provided in a therapeutically effective amount. In some cases, a therapeutically effective amount of a C5 inhibitor of the invention may be achieved by administration of a dose of from about 0.1 mg to about 1 mg, from about 0.5 mg to about 5 mg, from about 1 mg to about 20 mg, from about 5 mg to about 50 mg, from about 10 mg to about 100 mg, from about 20 mg to about 200 mg, or at least 200 mg of one or more C5 inhibitors. 
     In some embodiments, subjects may be administered a therapeutic amount of a C5 inhibitor (e.g., R5000 and/or active metabolites or variants thereof) based on the weight of such subjects. In some cases, C5 inhibitors are administered at a dose of from about 0.001 mg/kg to about 1.0 mg/kg, from about 0.01 mg/kg to about 2.0 mg/kg, from about 0.05 mg/kg to about 5.0 mg/kg, from about 0.03 mg/kg to about 3.0 mg/kg, from about 0.01 mg/kg to about 10 mg/kg, from about 0.1 mg/kg to about 2.0 mg/kg, from about 0.2 mg/kg to about 3.0 mg/kg, from about 0.4 mg/kg to about 4.0 mg/kg, from about 1.0 mg/kg to about 5.0 mg/kg, from about 2.0 mg/kg to about 4.0 mg/kg, from about 1.5 mg/kg to about 7.5 mg/kg, from about 5.0 mg/kg to about 15 mg/kg, from about 7.5 mg/kg to about 12.5 mg/kg, from about 10 mg/kg to about 20 mg/kg, from about 15 mg/kg to about 30 mg/kg, from about 20 mg/kg to about 40 mg/kg, from about 30 mg/kg to about 60 mg/kg, from about 40 mg/kg to about 80 mg/kg, from about 50 mg/kg to about 100 mg/kg, or at least 100 mg/kg. Such ranges may include ranges suitable for administration to human subjects. Dosage levels may be highly dependent on the nature of the condition; drug efficacy; the condition of the patient; the judgment of the practitioner; and the frequency and mode of administration. In some embodiments, R5000 and/or active metabolites or variants thereof may be administered at a dose of from about 0.01 mg/kg to about 10 mg/kg. In some cases R5000 and/or active metabolites or variants thereof may be administered at a dose of from about 0.1 mg/kg to about 3 mg/kg. 
     In some cases, C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) are provided at concentrations adjusted to achieve a desired level the C5 inhibitor in a sample, biological system, or subject (e.g., plasma level in a subject). In some cases, desired concentrations of C5 inhibitors in a sample, biological system, or subject may include concentrations of from about 0.001 μM to about 0.01 μM, from about 0.005 μM to about 0.05 μM, from about 0.02 μM to about 0.2 μM, from about 0.03 μM to about 0.3 μM, from about 0.05 μM to about 0.5 μM, from about 0.01 μM to about 2.0 μM, from about 0.1 μM to about 50 μM, from about 0.1 μM to about 10 μM, from about 0.1 μM to about 5 μM, from about 0.2 μM to about 20 μM, from about 5 μM to about 100 or from about 15 μM to about 200 μM. In some cases, desired concentrations of C5 inhibitors in subject plasma may be from about 0.1 μg/mL to about 1000 μg/mL. The desired concentration of C5 inhibitors in subject plasma may be from about 0.01 μg/mL to about 2 μg/mL, from about 0.02 μg/mL to about 4 μg/mL, from about 0.05 μg/mL to about 5 μg/mL, from about 0.1 μg/mL to about 1.0 μg/mL, from about 0.2 μg/mL to about 2.0 μg/mL, from about 0.5 μg/mL to about 5 μg/mL, from about 1 μg/mL to about 5 μg/mL, from about 2 μg/mL to about 10 μg/mL, from about 3 μg/mL to about 9 μg/mL, from about 5 μg/mL to about 20 μg/mL, from about 10 μg/mL to about 40 μg/mL, from about 30 μg/mL to about 60 μg/mL, from about 40 μg/mL to about 80 μg/mL, from about 50 μg/mL to about 100 μg/mL, from about 75 μg/mL to about 150 μg/mL, or at least 150 μg/mL. In other embodiments, C5 inhibitors are administered at a dose sufficient to achieve a maximum serum concentration (C max ) of at least 0.1 μg/mL, at least 0.5 μg/mL, at least 1 μg/mL, at least 5 μg/mL, at least 10 μg/mL, at least 50 μg/mL, at least 100 μg/mL, or at least 1000 μg/mL. 
     In some embodiments, doses sufficient to sustain C5 inhibitor levels of from about 0.1 μg/mL to about 30 μg/mL are provided to reduce hemolysis in a subject by from about 25% to about 99%. 
     In some embodiments, C5 inhibitors (e.g., R5000 and/or active metabolites or variants thereof) are administered daily at a dose sufficient to deliver from about 0.1 mg/day to about 60 mg/day per kg weight of a subject. In some cases, the C max  achieved with each dose is from about 0.1 μg/mL to about 1000 μg/mL. In such cases, the area under the curve (AUC) between doses may be from about 200 μg*hr/mL to about 10,000 μg*hr/mL. 
     According to some methods of the invention, C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) are provided at concentrations needed to achieve a desired effect. In some cases, compounds and compositions of the invention are provided at an amount necessary to reduce a given reaction or process by half. The concentration needed to achieve such a reduction is referred to herein as the half maximal inhibitory concentration, or “IC 50 .” Alternatively, compounds and compositions of the invention may be provided at an amount necessary to increase a given reaction, activity or process by half. The concentration needed for such an increase is referred to herein as the half maximal effective concentration or “EC 50 .” 
     The C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) may be present in amounts totaling 0.1-95% by weight of the total weight of the composition. In some cases, C5 inhibitors are provided by intravenous (IV) administration. In some cases, C5 inhibitors are provided by subcutaneous (SC) administration. 
     SC administration of C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) may, in some cases, provide advantages over IV administration. SC administration may allow patients to provide self-treatment. Such treatment may be advantageous in that patients could provide treatment to themselves in their own home, avoiding the need to travel to a provider or medical facility. Further, SC treatment may allow patients to avoid long-term complications associated with IV administration, such as infections, loss of venous access, local thrombosis, and hematomas. In some embodiments, SC treatment may increase patient compliance, patient satisfaction, quality of life, reduce treatment costs and/or drug requirements. 
     In some cases, daily SC administration provides steady-state C5 inhibitor concentrations that are reached within 1-3 doses, 2-3 doses, 3-5 doses, or 5-10 doses. In some cases, daily SC doses of 0.1 mg/kg may achieve sustained C5 inhibitor levels greater than or equal to 2.5 μg/mL and/or inhibition of complement activity of greater than 90%. 
     C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) may exhibit slow absorption kinetics (time to maximum observed concentration of greater than 4-8 hours) and high bioavailability (from about 75% to about 100%) after SC administration. 
     In some embodiments, dosage and/or administration are altered to modulate the half-life (t 1/2 ) of C5 inhibitor levels in a subject or in subject fluids (e.g., plasma). In some cases, t 1/2  is at least 1 hour, at least 2 hrs, at least 4 hrs, at least 6 hrs, at least 8 hrs, at least 10 hrs, at least 12 hrs, at least 16 hrs, at least 20 hrs, at least 24 hrs, at least 36 hrs, at least 48 hrs, at least 60 hrs, at least 72 hrs, at least 96 hrs, at least 5 days, at least 6 days, at least 7 days, at least 8 days, at least 9 days, at least 10 days, at least 11 days, at least 12 days, at least 2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at least 6 weeks, at least 7 weeks, at least 8 weeks, at least 9 weeks, at least 10 weeks, at least 11 weeks, at least 12 weeks, or at least 16 weeks. 
     In some embodiments, C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) may exhibit long terminal t 1/2 . Extended terminal t 1/2  may be due to extensive target binding and/or additional plasma protein binding. In some cases, C5 inhibitors of the invention exhibit t 1/2  values greater than 24 hours in both plasma and whole blood. In some cases, C5 inhibitors do not lose functional activity after incubation in human whole blood at 37° C. for 16 hours. 
     In some embodiments, dosage and/or administration are altered to modulate the steady state volume of distribution of C5 inhibitors. In some cases, the steady state volume of distribution of C5 inhibitors is from about 0.1 mL/kg to about 1 mL/kg, from about 0.5 mL/kg to about 5 mL/kg, from about 1 mL/kg to about 10 mL/kg, from about 5 mL/kg to about 20 mL/kg, from about 15 mL/kg to about 30 mL/kg, from about 10 mL/kg to about 200 mL/kg, from about 20 mL/kg to about 60 mL/kg, from about 30 mL/kg to about 70 mL/kg, from about 50 mL/kg to about 200 mL/kg, from about 100 mL/kg to about 500 mL/kg, or at least 500 mL/kg. In some cases, the dosage and/or administration of C5 inhibitors is adjusted to ensure that the steady state volume of distribution is equal to at least 50% of total blood volume. In some embodiments, C5 inhibitor distribution may be restricted to the plasma compartment. 
     In some embodiments, C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) exhibit a total clearance rate of from about 0.001 mL/hr/kg to about 0.01 mL/hr/kg, from about 0.005 mL/hr/kg to about 0.05 mL/hr/kg, from about 0.01 mL/hr/kg to about 0.1 mL/hr/kg, from about 0.05 mL/hr/kg to about 0.5 mL/hr/kg, from about 0.1 mL/hr/kg to about 1 mL/hr/kg, from about 0.5 mL/hr/kg to about 5 mL/hr/kg, from about 0.04 mL/hr/kg to about 4 mL/hr/kg, from about 1 mL/hr/kg to about 10 mL/hr/kg, from about 5 mL/hr/kg to about 20 mL/hr/kg, from about 15 mL/hr/kg to about 30 mL/hr/kg, or at least 30 mL/hr/kg. 
     Time periods for which maximum concentration of C5 inhibitors in subjects (e.g., in subject serum) are maintained (T max  values) may be adjusted by altering dosage and/or administration (e.g., subcutaneous administration). In some cases, C5 inhibitors have T max  values of from about 1 min to about 10 min, from about 5 min to about 20 min, from about 15 min to about 45 min, from about 30 min to about 60 min, from about 45 min to about 90 min, from about 1 hour to about 48 hrs, from about 2 hrs to about 10 hrs, from about 5 hrs to about 20 hrs, from about 10 hrs to about 60 hrs, from about 1 day to about 4 days, from about 2 days to about 10 days, or at least 10 days. 
     In some embodiments, C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) may be administered without off-target effects. In some cases, C5 inhibitors of the invention do not inhibit hERG (human ether-a-go-go related gene), even with concentrations less than or equal to 300 μM. SC injection of C5 inhibitors of the invention with dose levels up to 10 mg/kg may be well tolerated and not result in any adverse effects of the cardiovascular system (e.g., elevated risk of prolonged ventricular repolarization) and/or respiratory system. 
     C5 inhibitor doses may be determined using the no observed adverse effect level (NOAEL) observed in another species. Such species may include, but are not limited to monkeys, rats, rabbits, and mice. In some cases, human equivalent doses (HEDs) may be determined by allometric scaling from NOAELs observed in other species. In some cases, HEDs result in therapeutic margins of from about 2 fold to about 5 fold, from about 4 fold to about 12 fold, from about 5 fold to about 15 fold, from about 10 fold to about 30 fold, or at least 30 fold. In some cases, therapeutic margins are determined by using exposure in primates and estimated human C max  levels in humans. 
     In some embodiments, C5 inhibitors of the invention allow for a rapid washout period in cases of infection where prolonged inhibition of the complement system prove detrimental. 
     C5 inhibitor administration according to the invention may be modified to reduce potential clinical risks to subjects. Infection with  Neisseria meningitidis  is a known risk of C5 inhibitors, including eculizumab. In some cases, risk of infection with  Neisseria meningitides  is minimized by instituting one or more prophylactic steps. Such steps may include the exclusion of subjects who may already be colonized by these bacteria. In some cases, prophylactic steps may include coadministration with one or more antibiotics. In some cases, ciprofloxacin may be coadministered. In some cases, ciprofloxacin may be coadministered orally at a dose of from about 100 mg to about 1000 mg (e.g., 500 mg). 
     In some embodiments, C5 inhibitor administration may be carried out using an auto-injector device. Such devices may allow for self-administration (e.g., daily administration). 
     In some embodiments, R5000 and/or active metabolites or variants thereof may be co-administered with eculizumab. Co-administration may be carried out to reduce residual C5 activity associated with eculizumab treatment alone (e.g., due to incomplete inhibition). 
     Dosage Frequency 
     In some embodiments, C5 inhibitors of the invention (e.g., R5000 and/or active metabolites or variants thereof) are administered at a frequency of every hour, every 2 hrs, every 4 hrs, every 6 hrs, every 12 hrs, every 18 hrs, every 24 hrs, every 36 hrs, every 72 hrs, every 84 hrs, every 96 hrs, every 5 days, every 7 days, every 10 days, every 14 days, every week, every two weeks, every 3 weeks, every 4 weeks, every month, every 2 months, every 3 months, every 4 months, every 5 months, every 6 months, every year, or at least every year. In some cases, C5 inhibitors are administered once daily or administered as two, three, or more sub-doses at appropriate intervals throughout the day. 
     In some embodiments, C5 inhibitors are administered in multiple daily doses. In some cases, C5 inhibitors are administered daily for 7 days. In some cases, C5 inhibitors are administered daily for 7 to 100 days. In some cases, C5 inhibitors are administered daily for at least 100 days. In some cases, C5 inhibitors are administered daily for an indefinite period. 
     C5 inhibitors delivered intravenously may be delivered by infusion over a period of time, such as over a 5 minute, 10 minute, 15 minute, 20 minute, or 25 minute period. The administration may be repeated, for example, on a regular basis, such as hourly, daily, weekly, biweekly (i.e., every two weeks), for one month, two months, three months, four months, or more than four months. After an initial treatment regimen, treatments may be administered on a less frequent basis. For example, after biweekly administration for three months, administration may be repeated once per month, for six months or a year or longer. Administration C5 inhibitor may reduce, lower, increase or alter binding or any physiologically deleterious process (e.g., in a cell, tissue, blood, urine or other compartment of a patient) by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% or more. 
     Before administration of a full dose of the C5 inhibitor and/or C5 inhibitor composition, patients can be administered a smaller dose, such as 5% of a full dose, and monitored for adverse effects, such as an allergic reaction or infusion reaction, or for elevated lipid levels or blood pressure. In another example, the patient can be monitored for unwanted immunostimulatory effects, such as increased cytokine (e.g., TNF-alpha, IL-1, IL-6, or IL-10) levels. 
     Genetic predisposition plays a role in the development of some diseases or disorders. Therefore, a patient in need of a C5 inhibitor may be identified by taking a family history, or, for example, screening for one or more genetic markers or variants. A healthcare provider, such as a doctor, nurse, or family member, may analyze family history before prescribing or administering a therapeutic composition of the present invention. 
     C5 Assays 
     In some embodiments, the present disclosure provides compounds and methods for the detection of C5 and/or C5-associating factors in samples. With some methods, total C5 is detected. Total C5 may include both free C5 and C5 associated with one or more C5-associating factors. C5-associating factors may include antibodies (e.g., eculizumab or similar antibody binding to a similar epitope). According to such embodiments, samples may be added to a substrate, wherein the substrate includes a capture agent that associates with C5. The capture agent may bind to C5 on a region of C5 that is non-overlapping with a portion of the C5 protein recognized by a C5-associating factor. Both free C5 and C5 associated with one or more C5-associating factors may be captured by capture agents to facilitate detection using one or more detection agents. As used herein, a “detection agent” is any factor that facilitates recognition of an analyte, interaction, reaction, process, or event. In some embodiments, detection agents are detection antibodies. Detection agents may bind to an analyte to facilitate recognition of the analyte&#39;s presence or absence. Detection agents used to detect capture of free C5 may bind to C5 on a region that is non-overlapping with a region bound by the capture agent or a C5-associating factor. Detection agents used to detect capture of C5 associated with one or more C5-associating factors may bind to the C5-associating factor. Detection agents may include a detectable label. 
     As used herein, the term “detectable label” refers to one or more markers, signals, or moieties which are attached, incorporated, or associated with another entity, which markers, signals or moieties are readily detected by methods known in the art including, but not limited to, radiography, fluorescence, chemiluminescence, enzymatic activity, absorbance and the like. Detectable labels may include, but are not limited to, radioisotopes, fluorophores, chromophores, enzymes, dyes, metal ions, ligands (e.g., biotin, avidin, streptavidin, and haptens, such as digoxigenin), quantum dots, and the like. Detectable labels may be located at any position of the entity with which they are attached, incorporated or associated. For example, when attached, incorporated in, or associated with a peptide or protein, detectable labels may be within the amino acids, the peptides, or proteins, or located at the N- or C-termini. 
     In some embodiments, detection agents may be detected using a secondary detection agent that binds to the detection agent or a detectable label associated with the detection agent. The secondary detection agent may include an antibody. The secondary detection agent may be associated with a detectable label to facilitate detection (e.g., through fluorescent, radiographic, colorimetric, enzymatic, or other detection methods). In one embodiment, the detection agent includes digoxigenin. The digoxigenin may be detected using an anti-digoxigenin antibody. 
     Assay substrates may include surfaces capable of retaining capture agents. Capture agents may be immobilized to substrates, e.g., through covalent or non-covalent interactions. In some embodiments, capture agents are biotinylated to facilitate substrate immobilization with substrates having a biotin-interacting compound (e.g., avidin, neutravidin, or streptavidin). Substrates may include, but are not limited to, assay plates. In some embodiments, substrates are beads. 
     C5 capture agents may include any compounds capable of associating with C5. In some embodiments, capture agents include peptides or peptide-based compounds. Capture agents may include R5000 or variants thereof. In some assays, a variant of R5000 is used wherein the variant includes an N-terminal biotinylated PEG moiety to facilitate substrate immobilization. Some R5000 variants may further include substitution of the C-terminal lysine with another compound. The compound may be another amino acid, for example, any natural or non-natural amino acid. Some R5000 variants have substitutions of the C-terminal lysine with norvaline. 
     In some embodiments, the present disclosure provides a method of measuring C5 or C5 levels in a sample by immobilizing a capture agent on a substrate, wherein the capture agent binds to a site on C5 that is distinct from the eculizumab binding site; contacting the substrate with the sample, wherein the immobilized capture agent binds to C5 in the sample; contacting the substrate with a detection agent (e.g., an antibody), and measuring the presence or level of the detection agent as an indicator of C5 levels in the sample. The detection agent may include a detectable label. The detection agent may be detected using a secondary detection agent. The detection agent may be an anti-C5 antibody (e.g., eculizumab or non-eculizumab anti-C5 antibody). The method may include contacting the substrate with a second detection agent (e.g., an antibody), wherein the second detection agent binds to a C5-associated factor (e.g., eculizumab). Measurement of the level of the second detection antibody bound to the substrate may be carried out as an indicator of C5-associated factor levels in the sample. In some embodiments, both free C5 levels and eculizumab-associated C5 levels are measured using assays disclosed herein. The levels may be combined levels, yielding total C5 levels in samples having both forms. In some embodiments, fee C5 levels and eculizumab-associated C5 levels are distinguished. 
     In some embodiments, the present disclosure provides methods for measuring free eculizumab levels in a sample by immobilizing a capture agent on a substrate, where the capture agent binds to a site on C5 that is distinct from the eculizumab binding site; contacting the substrate with an excess of C5 to form a C5-capture agent complex, wherein the C5-capture agent complex comprises immobilized C5; contacting the substrate with the sample, wherein the immobilized C5 binds to eculizumab in the sample; contacting the substrate with a detection agent, wherein the detection agent binds to eculizumab; and measuring the level of bound detection agent as an indicator of free eculizumab levels in the sample. Capture agents may include R5000 or variants thereof. In some assays, a variant of R5000 is used wherein the variant includes an N-terminal biotinylated PEG moiety to facilitate substrate immobilization. The R5000 variant may include a substitution of the C-terminal lysine with another compound. The compound may be another amino acid, for example, any natural or non-natural amino acid. The R5000 variant may have a substitution of the C-terminal lysine with norvaline. The detection agent may be an antibody. The detection agent may include a detectable label or be detected using a secondary detection agent. 
     III. Kits 
     Any of the C5 inhibitors described herein (e.g., R5000 and/or active metabolites or variants thereof) may be provided as part of a kit. In a non-limiting example, C5 inhibitors may be included in a kit for treating a disease. The kit may include a vial of sterile, dry C5 inhibitor powder, sterile solution for dissolving the dried powder, and a syringe for infusion set for administering the C5 inhibitor. 
     When C5 inhibitors are provided as a dried powder it is contemplated that between 10 micrograms and 1000 milligrams of C5 inhibitor, or at least or at most those amounts are provided in kits of the invention 
     Typical kits may include at least one vial, test tube, flask, bottle, syringe and/or other container or device, into which the C5 inhibitor formulations are placed, preferably, suitably allocated. Kits may also include one or more secondary containers with sterile, pharmaceutically acceptable buffer and/or other diluent. 
     In some embodiments, compounds or compositions of the invention are provided in borosilicate vials. Such vials may include a cap (e.g., a rubber stopper). In some cases, caps include FLUROTEC® coated rubber stoppers. Caps may be secured in place with an overseal, including, but not limited to an aluminum flip-off overseal. 
     Kits may further include instructions for employing the kit components as well the use of any other reagent not included in the kit. Instructions may include variations that can be implemented. 
     IV. Definitions 
     Bioavailability: As used herein, the term “bioavailability” refers to the systemic availability of a given amount of a compound (e.g., C5 inhibitor) administered to a subject. Bioavailability can be assessed by measuring the area under the curve (AUC) or the maximum serum or plasma concentration (C max ) of the unchanged form of a compound following administration of the compound to a subject. AUC is a determination of the area under the curve when plotting the serum or plasma concentration of a compound along the ordinate (Y-axis) against time along the abscissa (X-axis). Generally, the AUC for a particular compound can be calculated using methods known to those of ordinary skill in the art and/or as described in G. S. Banker, Modern Pharmaceutics, Drugs and the Pharmaceutical Sciences, v. 72, Marcel Dekker, New York, Inc., 1996, the contents of which are herein incorporated by reference in their entirety. 
     Biological system: As used herein, the term “biological system” refers to a cell, a group of cells, a tissue, an organ, a group of organs, an organelle, a biological fluid, a biological signaling pathway (e.g., a receptor-activated signaling pathway, a charge-activated signaling pathway, a metabolic pathway, a cellular signaling pathway, etc.), a group of proteins, a group of nucleic acids, or a group of molecules (including, but not limited to biomolecules) that carry out at least one biological function or biological task within cellular membranes, cellular compartments, cells, cell cultures, tissues, organs, organ systems, organisms, multicellular organisms, biological fluids, or any biological entities. In some embodiments, biological systems are cell signaling pathways comprising intracellular and/or extracellular signaling biomolecules. In some embodiments, biological systems include proteolytic cascades (e.g., the complement cascade). 
     Buffering agent: As used herein, the term “buffering agent” refers to a compound used in a solution for the purposes of resisting changes in pH. Such compounds may include, but are not limited to acetic acid, adipic acid, sodium acetate, benzoic acid, citric acid, sodium benzoate, maleic acid, sodium phosphate, tartaric acid, lactic acid, potassium metaphosphate, glycine, sodium bicarbonate, potassium phosphate, sodium citrate, and sodium tartrate. 
     Clearance rate: As used herein, the term “clearance rate” refers to the velocity at which a particular compound is cleared from a biological system or fluid. 
     Compound: As used herein, the term “compound,” refers to a distinct chemical entity. In some embodiments, a particular compound may exist in one or more isomeric or isotopic forms (including, but not limited to stereoisomers, geometric isomers and isotopes). In some embodiments, a compound is provided or utilized in only a single such form. In some embodiments, a compound is provided or utilized as a mixture of two or more such forms (including, but not limited to a racemic mixture of stereoisomers). Those of skill in the art will appreciate that some compounds exist in different forms, show different properties and/or activities (including, but not limited to biological activities). In such cases it is within the ordinary skill of those in the art to select or avoid particular forms of a compound for use in accordance with the present invention. For example, compounds that contain asymmetrically substituted carbon atoms can be isolated in optically active or racemic forms. 
     Cyclic or Cyclized: As used herein, the term “cyclic” refers to the presence of a continuous loop. Cyclic molecules need not be circular, only joined to form an unbroken chain of subunits. Cyclic polypeptides may include a “cyclic loop,” formed when two amino acids are connected by a bridging moiety. The cyclic loop comprises the amino acids along the polypeptide present between the bridged amino acids. Cyclic loops may comprise 2, 3, 4, 5, 6, 7, 8, 9, 10 or more amino acids. 
     Downstream event: As used herein, the term “downstream” or “downstream event,” refers to any event occurring after and/or as a result of another event. In some cases, downstream events are events occurring after and as a result of C5 cleavage and/or complement activation. Such events may include, but are not limited to generation of C5 cleavage products, activation of MAC, hemolysis, and hemolysis-related disease (e.g., PNH). 
     Equilibrium dissociation constant: As used herein, the term “equilibrium dissociation constant” or “K D ” refers to a value representing the tendency of two or more agents (e.g., two proteins) to reversibly separate. In some cases, K D  indicates a concentration of a primary agent at which half of the total levels of a secondary agent are associated with the primary agent. 
     Half-life: As used herein, the term “half-life” or “t 1/2 ” refers to the time it takes for a given process or compound concentration to reach half of a final value. The “terminal half-life” or “terminal t 1/2 ” refers to the time needed for the plasma concentration of a factor to be reduced by half after the concentration of the factor has reached a pseudo-equilibrium. 
     Hemolysis: As used herein, the term “hemolysis” refers to the destruction of red blood cells. 
     Identity: As used herein, the term “identity,” when referring to polypeptides or nucleic acids, refers to a comparative relationship between sequences. The term is used to describe the degree of sequence relatedness between polymeric sequences, and may include the percentage of matching monomeric components with gap alignments (if any) addressed by a particular mathematical model or computer program (i.e., “algorithms”). Identity of related polypeptides can be readily calculated by known methods. Such methods include, but are not limited to, those described previously by others (Lesk, A. M., ed., Computational Molecular Biology, Oxford University Press, New York, 1988; Smith, D. W., ed., Biocomputing: Informatics and Genome Projects, Academic Press, New York, 1993; Griffin, A. M. et al., ed., Computer Analysis of Sequence Data, Part 1, Humana Press, New Jersey, 1994; von Heinje, G., Sequence Analysis in Molecular Biology, Academic Press, 1987; Gribskov, M. et al., ed., Sequence Analysis Primer, M. Stockton Press, New York, 1991; and Carillo et al., Applied Math, SIAM J, 1988, 48, 1073). 
     Inhibitor: As used herein, the term “inhibitor” refers to any agent that blocks or causes a reduction in the occurrence of a specific event; cellular signal; chemical pathway; enzymatic reaction; cellular process; interaction between two or more entities; biological event; disease; disorder; or condition. 
     Initial loading dose: As used herein, an “initial loading dose” refers to a first dose of a therapeutic agent that may differ from one or more subsequent doses. Initial loading doses may be used to achieve an initial concentration of a therapeutic agent or level of activity before subsequent doses are administered. 
     Intravenous: As used herein, the term “intravenous” refers to the area within a blood vessel. Intravenous administration typically refers to delivery of a compound into the blood through injection in a blood vessel (e.g., vein). 
     In vitro: As used herein, the term “in vitro” refers to events that occur in an artificial environment (e.g., in a test tube or reaction vessel, in cell culture, in a Petri dish, etc.), rather than within an organism (e.g., animal, plant, or microbe). 
     In vivo: As used herein, the term “in vivo” refers to events that occur within an organism (e.g., animal, plant, or microbe or cell or tissue thereof). 
     Lactam bridge: As used herein, the term “lactam bridge” refers to an amide bond that forms a bridge between chemical groups in a molecule. In some cases, lactam bridges are formed between amino acids in a polypeptide. 
     Linker: The term “linker” as used herein refers to a group of atoms (e.g., 10-1,000 atoms), molecule(s), or other compounds used to join two or more entities. Linkers may join such entities through covalent or non-covalent (e.g., ionic or hydrophobic) interactions. Linkers may include chains of two or more polyethylene glycol (PEG) units. In some cases, linkers may be cleavable. 
     Minute volume: As used herein, the term “minute volume” refers to the volume of air inhaled or exhaled from a subject&#39;s lungs per minute. 
     Non-proteinogenic: As used herein, the term “non-proteinogenic” refers to any unnatural proteins, such as those with unnatural components, such as unnatural amino acids. 
     Patient: As used herein, “patient” refers to a subject who may seek or be in need of treatment, requires treatment, is receiving treatment, will receive treatment, or a subject who is under the care of a trained professional for a particular disease or condition. 
     Pharmaceutical composition: As used herein, the term “pharmaceutical composition” refers to a composition comprising at least one active ingredient (e.g., a C5 inhibitor) in a form and amount that permits the active ingredient to be therapeutically effective. 
     Pharmaceutically acceptable: The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. 
     Pharmaceutically acceptable excipients: The phrase “pharmaceutically acceptable excipient,” as used herein, refers any ingredient other than active agents (e.g., active agent R5000 and/or active metabolites thereof or variants thereof) present in a pharmaceutical composition and having the properties of being substantially nontoxic and non-inflammatory in a patient. In some embodiments, a pharmaceutically acceptable excipient is a vehicle capable of suspending or dissolving the active agent. Excipients may include, for example: antiadherents, antioxidants, binders, coatings, compression aids, disintegrants, dyes (colors), emollients, emulsifiers, fillers (diluents), film formers or coatings, flavors, fragrances, glidants (flow enhancers), lubricants, preservatives, printing inks, sorbents, suspensing or dispersing agents, sweeteners, and waters of hydration. Exemplary excipients include, but are not limited to: butylated hydroxytoluene (BHT), calcium carbonate, calcium phosphate (dibasic), calcium stearate, croscarmellose, crosslinked polyvinyl pyrrolidone, citric acid, crospovidone, cysteine, ethylcellulose, gelatin, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, maltitol, mannitol, methionine, methylcellulose, methyl paraben, microcrystalline cellulose, polyethylene glycol, polyvinyl pyrrolidone, povidone, pregelatinized starch, propyl paraben, retinyl palmitate, shellac, silicon dioxide, sodium carboxymethyl cellulose, sodium citrate, sodium starch glycolate, sorbitol, starch (corn), stearic acid, sucrose, talc, titanium dioxide, vitamin A, vitamin E, vitamin C, and xylitol. 
     Plasma compartment: As used herein, the term “plasma compartment” refers to intravascular space occupied by blood plasma. 
     Salt: As used herein, the term “salt” refers to a compound made up of a cation with a bound anion. Such compounds may include sodium chloride (NaCl) or other classes of salts including, but not limited to acetates, chlorides, carbonates, cyanides, nitrites, nitrates, sulfates, and phosphates. 
     Sample: As used herein, the term “sample” refers to an aliquot or portion taken from a source and/or provided for analysis or processing. In some embodiments, a sample is from a biological source such as a tissue, cell or component part (e.g., a body fluid, including but not limited to blood, mucus, lymphatic fluid, synovial fluid, cerebrospinal fluid, saliva, amniotic fluid, amniotic cord blood, urine, vaginal fluid and semen). In some embodiments, a sample may be or comprise a homogenate, lysate or extract prepared from a whole organism or a subset of its tissues, cells or component parts, or a fraction or portion thereof, including but not limited to, for example, plasma, serum, spinal fluid, lymph fluid, the external sections of the skin, respiratory, intestinal, and genitourinary tracts, tears, saliva, milk, blood cells, tumors, or organs. In some embodiments, a sample is or comprises a medium, such as a nutrient broth or gel, which may contain cellular components, such as proteins. In some embodiments, a “primary” sample is an aliquot of the source. In some embodiments, a primary sample is subjected to one or more processing (e.g., separation, purification, etc.) steps to prepare a sample for analysis or other use. 
     Subcutaneous: As used herein, the term “subcutaneous” refers to the space underneath the skin. Subcutaneous administration is delivery of a compound beneath the skin. 
     Subject: As used herein, the term “subject” refers to any organism to which a compound in accordance with the invention may be administered, e.g., for experimental, diagnostic, prophylactic, and/or therapeutic purposes. Typical subjects include animals (e.g., mammals such as mice, rats, rabbits, porcine subjects, non-human primates, and humans). 
     Substantially: As used herein, the term “substantially” refers to the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest. One of ordinary skill in the biological arts will understand that biological and chemical phenomena rarely, if ever, go to completion and/or proceed to completeness or achieve or avoid an absolute result. The term “substantially” is therefore used herein to capture the potential lack of completeness inherent in many biological and chemical phenomena. 
     Therapeutically effective amount: As used herein, the term “therapeutically effective amount” means an amount of an agent to be delivered (e.g., C5 inhibitor) that is sufficient, when administered to a subject suffering from or susceptible to a disease, disorder, and/or condition, to treat, improve symptoms of, diagnose, prevent, and/or delay the onset of the disease, disorder, and/or condition. 
     Tidal volume: As used herein, the term “tidal volume” refers to the normal lung volume of air displaced between breaths (in the absence of any extra effort). 
     T max : As used herein, the term “T max ” refers to the time period for which maximum concentration of a compound in a subject or fluid is maintained. 
     Treating: As used herein, the term “treating” refers to partially or completely alleviating, ameliorating, improving, relieving, delaying onset of, inhibiting progression of, reducing severity of, and/or reducing incidence of one or more symptoms or features of a particular disease, disorder, and/or condition. Treatment may be administered to a subject who does not exhibit signs of a disease, disorder, and/or condition and/or to a subject who exhibits only early signs of a disease, disorder, and/or condition for the purpose of decreasing the risk of developing pathology associated with the disease, disorder, and/or condition. 
     Treatment dose: As used herein, “treatment dose” refers to one or more doses of a therapeutic agent administered in the course of addressing or alleviating a therapeutic indication. Treatment doses may be adjusted to maintain a desired concentration or level of activity of a therapeutic agent in a body fluid or biological system. 
     Volume of distribution: As used herein, the term “volume of distribution” or “V dist ” refers to a fluid volume required to contain the total amount of a compound in the body at the same concentration as in the blood or plasma. The volume of distribution may reflect the extent to which a compound is present in the extravascular tissue. A large volume of distribution reflects the tendency of a compound to bind to tissue components compared with plasma protein components. In a clinical setting, V dist  can be used to determine a loading dose of a compound to achieve a steady state concentration of that compound. 
     V. Equivalents and Scope 
     While various embodiments of the invention have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. 
     Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments in accordance with the invention described herein. The scope of the present invention is not intended to be limited to the above description, but rather is as set forth in the appended claims. 
     In the claims, articles such as “a,” “an,” and “the” may mean one or more than one unless indicated to the contrary or otherwise evident from the context. Claims or descriptions that include “or” between one or more members of a group are considered satisfied if one, more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process unless indicated to the contrary or otherwise evident from the context. The invention includes embodiments in which exactly one member of the group is present in, employed in, or otherwise relevant to a given product or process. The invention includes embodiments in which more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process. 
     It is also noted that the term “comprising” is intended to be open and permits but does not require the inclusion of additional elements or steps. When the term “comprising” is used herein, the terms “consisting of” and “or including” are thus also encompassed and disclosed. 
     Where ranges are given, endpoints are included. Furthermore, it is to be understood that unless otherwise indicated or otherwise evident from the context and understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value or subrange within the stated ranges in different embodiments of the invention, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise. 
     In addition, it is to be understood that any particular embodiment of the present invention that falls within the prior art may be explicitly excluded from any one or more of the claims. Since such embodiments are deemed to be known to one of ordinary skill in the art, they may be excluded even if the exclusion is not set forth explicitly herein. Any particular embodiment of the compositions of the invention (e.g., any nucleic acid or protein encoded thereby; any method of production; any method of use; etc.) can be excluded from any one or more claims, for any reason, whether or not related to the existence of prior art. 
     All cited sources, for example, references, publications, databases, database entries, and art cited herein, are incorporated into this application by reference, even if not expressly stated in the citation. In case of conflicting statements of a cited source and the instant application, the statement in the instant application shall control. 
     Section and table headings are not intended to be limiting. 
     EXAMPLES 
     Example 1. Preparation of R5000 Aqueous Solution 
     Polypeptides were synthesized using standard solid-phase Fmoc/tBu methods. The synthesis was performed on a Liberty automated microwave peptide synthesizer (CEM, Matthews N.C.) using standard protocols with Rink amide resin, although other automated synthesizers without microwave capability may also be used. All amino acids were obtained from commercial sources. The coupling reagent used was 2-(6-chloro-1-H-benzotriazole-1yl)-1,1,3,3,-tetramethylaminium hexafluorophosphate (HCTU) and the base was diisopropylethylamine (DIEA). Polypeptides were cleaved from resin with 95% TFA, 2.5% TIS and 2.5% water for 3 hours and isolated by precipitation with ether. The crude polypeptides were purified on a reverse phase preparative HPLC using a C18 column, with an acetonitrile/water 0.1% TFA gradient from 20%-50% over 30 min. Fractions containing pure polypeptides were collected and lyophilized and all polypeptides were analyzed by LC-MS. 
     R5000 (SEQ ID NO: 1) was prepared as a cyclic peptide containing 15 amino acids (4 of which are unnatural amino acids), an acetylated N-terminus, and a C-terminal carboxylic acid. The C-terminal lysine of the core peptide has a modified side chain, forming a N-ε-(PEG24-γ-glutamic acid-N-α-hexadecanoyl) lysine reside. This modified side chain includes a polyethyleneglycol spacer (PEG24) attached to an L-γ glutamic acid residue that is derivatized with a palmitoyl group. The cyclization of R5000 is via a lactam bridge between the side-chains of L-Lys1 and L-Asp6. All of the amino acids in R5000 are L-amino acids. R5000 has a molecular weight of 3562.23 g/mol and a chemical formula of C 172 H 278 N 24 O 55 . 
     Like eculizumab, R5000 blocks the proteolytic cleavage of C5 into C5a and C5b. Unlike eculizumab, R5000 can also bind to C5b and block C6 binding which prevents the subsequent assembly of the MAC. 
     R5000 was prepared as an aqueous solution for injection containing 40 mg/mL of R5000 in a formulation of 50 mM sodium phosphate and 76 mM sodium chloride at a pH of 7.0. The resulting composition was used to prepare a medicinal product, in accordance with current Good Manufacturing Practices (cGMPs), the medicinal product including a 1 ml syringe with a 29 gauge, ½ inch staked needle placed within a self-administration device. 
     Example 2. R5000 Administration and Storage 
     R5000 is administered by subcutaneous (SC) or intravenous (IV) injection and the dose administered (dose volume) is adjusted based on subject weight on a mg/kg basis. This is achieved using a set of fixed doses aligned to a set of weight brackets. In total, human dosing supports a broad weight range of 43 to 109 kg. Subjects who present with a higher body weight (&gt;109 kg) are accommodated on a case-by-case basis, in consultation with a medical monitor. 
     R5000 is stored at 2° C. to 8° C. [36° to 46° F.]. Once dispensed to subjects, R5000 is stored at controlled room temperature (20° C. to 25° C. [68° F. to 77° F.]) for up to 30 days, and is protected from sources of excessive temperature fluctuations such as high heat or exposure to light. Storage of R5000 outside of room temperatures is preferably avoided. R5000 may be stored for up to 30 days under these conditions. 
     Example 3. Stability Testing 
     Stability testing is carried out according to the International Conference on Harmonisation (ICH) Q1A “Stability of New Drug Substances and Products.” Samples from the aqueous solution of Example 1 are held at 3 temperatures: −20° C., 5° C., and 25° C. Testing intervals are at 1, 2, and 3 months, and thereafter every 3 months up to 24 months. Samples are tested for appearance (e.g., clarity, color, presence of precipitate), pH, osmolality, concentration, purity, target activity (e.g., by RBC lysis assay), particulate levels, endotoxin levels, and sterility. Samples are considered stable if, at each of the temperature conditions tested, the samples have a clear, colorless appearance with no visible particles; a pH of 7±0.3; an osmolality of 260 to 340 mOsm/kg; a purity of ≥95% (and no single impurity &gt;3%); target activity that is comparable to a reference standard; particulate levels of ≤6,000 particulates per vial for ≥10 μm particles and levels of ≤600 particulates per vial for ≥25 μm particles; endotoxin levels of ≤100 EU/mL; and no microorganism growth. 
     Example 4. Freeze-Thaw Stability 
     A study was conducted to test stability of the aqueous solution of Example 1 when exposed to multiple freezing and thawing cycles. R5000 showed no degradation or other changes after 5 cycles of freezing and thawing. 
     Example 5. Surface Plasmon Resonance (SPR)-Based Binding Evaluation 
     The binding interaction between R5000 and C5 was measured using surface plasmon resonance. R5000 bound C5 with an equilibrium dissociation constant (K D ) of 0.42 nM at 25° C. (n=3) and a K D  of 0.78 nM at 37° C. (n=3). Overall surface plasmon resonance data, when combined with analysis of a high-resolution co-crystal structure, indicate that R5000 exhibits specific, strong and rapid association with C5 as well as a slow dissociation rate. 
     Example 6. Evaluation of C5 Cleavage Inhibition 
     R5000 was assessed for inhibition of C5 cleavage to C5a and C5b by ELISA analysis of C5a cleavage product and C5b-9 membrane attack complex (MAC) formation. The inhibitory activity of R5000 with host C5 is an important factor in choosing appropriate animal models for drug safety. The inhibition of C5 cleavage is the basis for the clinical efficacy for eculizumab, currently the only approved therapy for the treatment of PNH. R5000 demonstrated a dose-dependent inhibition of C5a formation following activation of the Classical Pathway (IC 50 =4.8 nM;  FIG. 1 ) and a dose dependent inhibition of C5b (as measured by C5b-9 or MAC formation) upon activation of the Classical and Alternative complement pathways (IC 50 =5.1 nM;  FIG. 2 ). 
     Example 7. Inhibition of Complement-Induced Red Blood Cell (RBC) Hemolysis 
     The RBC lysis assay is a reliable method to screen complement inhibitors in sera/plasma from various species and compare relative activities of the test article. An in vitro functional assay was used in order to assess the inhibitory activity of peptides, including R5000, against complement function in several species. This assay tests the functional capability of complement components of the classical pathway to lyse sheep RBCs pre-coated with rabbit anti-sheep RBC antibodies. When antibody-coated RBCs are incubated with test serum, the classical pathway of complement is activated and hemolysis results and is monitored by release of hemoglobin. Antibody-sensitized sheep red blood cells were used as the vehicle for lysis in this assay and the sera and/or plasma from various species were used at their predetermined 50% hemolytic complement activity (CH 50 ). 
     R5000 demonstrated potent inhibition of complement-induced RBC hemolysis in the serum and/or plasma of human, non-human primates, and pigs (see Table 1). 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Inhibition of red blood cell hemolysis by R5000 in multiple species 
               
            
           
           
               
               
               
            
               
                   
                 Species 
                 IC 50  (nM) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 Human 
                 6.6 
               
               
                   
                 Non-human primate (4 species) 
                 3.5 to 17.6 
               
               
                   
                 Dog 
                 &gt;4700 
               
               
                   
                 Rabbit 
                 &gt;67000 
               
               
                   
                 Porcine (2 species) 
                 51.9 to 118.6 
               
               
                   
                 Rodents (3 species) 
                   591 to &gt;100000 
               
               
                   
                   
               
            
           
         
       
     
     Weak activity was observed in rat plasma (&gt;100 times lower than Cynomolgus monkey) and little to no activity was seen in other rodents, dog, or rabbit. Structural data obtained from a co-crystalization of human C5 with a molecule closely related to R5000 provided an explanation for this species selectivity through a careful analysis of the primary amino acid sequence at the drug-binding site of the target protein. While primate sequences are 100% conserved within residues responsible for R5000 interactions, there were significant differences in these residues in rodents and particularly in dog where identical portions of the protein do not exist. These amino acid differences were sufficient to explain the activity profiles of R5000 in different species. 
     The ability of R5000 to inhibit complement-mediated lysis of erythrocytes via the classical and alternative complement activation pathways was also tested. The classical pathway was evaluated using two different assays utilizing antibody-sensitized sheep erythrocytes. In one method, hemolysis was evaluated using 1% normal human serum, while the second assay utilized 1.5% C5-depleted human sera containing 0.5 nM human C5. The inhibition of the alternative complement activation pathway was evaluated using rabbit erythrocytes in 6% normal human serum in the absence of calcium (see Table 2). 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Inhibition of hemolysis by R5000 
               
               
                 in complement activation pathways 
               
            
           
           
               
               
               
            
               
                   
                 Pathway 
                 IC 50   
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 Classical pathway 
                 4.9 
               
               
                   
                 C5-depleted sera -classical pathway 
                 2.4 
               
               
                   
                 Alternative pathway 
                 59.2 
               
               
                   
                   
               
            
           
         
       
     
     R5000 demonstrated complement mediated lysis in both, the classical pathway assays and the alternative pathway assay. 
     Example 8. Pharmacodynamics in Cynomolgus Monkeys 
     R5000 is a potent inhibitor of complement in primates, thus Cynomolgus monkeys were selected for multi-dose studies to evaluate the inhibitory activity of R5000 in an animal model. Plasma drug concentrations were determined by LC-MS and complement activity was assayed using the RBC lysis assay described previously. Overall results from these studies indicated that plasma drug levels should be at or greater than 2.5 μg/mL in monkeys to achieve &gt;90% inhibition of complement activity (see  FIG. 3 ). 
     R5000 was administered to Cynomolgus monkeys at multiple daily doses through subcutaneous injections (SC) in a 7-day study. Blood samples were analyzed for hemolysis as an indicator of complement activity at the indicated time points (for days 1, 4, and 7, data are reported as days after first dose, but prior to dosing on the respective day) using an ex vivo sheep RBC lysis assay with 1% plasma in the assay. Drug levels were determined from the same sample using an LC-MS method specific for R5000. As shown in Table 3 and in  FIG. 4  and  FIG. 5 , when R5000 was administered daily for 7 days at either 0.21 or 4.2 mg/kg, minimal (&lt;3% of pre-dose) complement activity was seen throughout the dosing period. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Mean pharmacodynamic values 
               
            
           
           
               
               
               
               
               
            
               
                 # of 
                 Daily 
                   
                 Last point 
                 % Hemolysis 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Animals 
                 Dose 
                   
                 collected 
                 Day 
                 Day 
                 Day 
                 Day 
                 Day 
                 Day 
                 Day 
               
               
                 dosed 
                 (mg/kg) 
                 Route 
                 (days) 
                 1 
                 4 
                 7 
                 8 
                 12 
                 14 
                 18 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 2 
                 0.21 
                 SC 
                 18 
                 2.9 
                 1.9 
                 2.4 
                 5.4 
                 75.4 
                 &gt;95 
                 &gt;95 
               
               
                 2 
                 4.2 
                 SC 
                 18 
                 &lt;1 
                 &lt;1 
                 &lt;1 
                 1.1 
                 8.7 
                 45.7 
                 87.3 
               
               
                   
               
            
           
         
       
     
     Hemolysis in the ex vivo assay was maintained below 90% of baseline after the first dose in the 0.21 mg/kg group, throughout the dosing period, and up to 24 hours after the last dose. Increasing levels of hemolysis were seen after treatment was discontinued. By Day 4 (264 hours in  FIG. 4 ) after the last dose was administered, hemolysis was &gt;75% of baseline. This correlates well with the measured plasma levels for the compound during and after dosing (dotted line in  FIG. 4 ). The second group of animals in the multi-dose study was administered daily 4.2 mg/kg doses of R5000. In this group, hemolysis was essentially completely inhibited (at &lt;1%) throughout dosing and remained below 3% at 48 hours after the last dose (Day 9; 216 hours in  FIG. 5 ). Four days after the final dose (264 hours in  FIG. 5 ), hemolysis reached approximately 10% of baseline. This result again demonstrated suppression of complement activity throughout the dosing period (as compared to pre-dose results) correlating with plasma drug concentrations and demonstrated an excellent correlation between pharmacokinetic and pharmacodynamic values. 
     The complement inhibitory activity of R5000 was assessed in a 28 day-repeated-dose study in Cynomolgus monkey using the ex vivo RBC hemolysis assay. R5000 was administered daily via subcutaneous injection for 28 days at either 0, 1, 2, or 4 mg/kg/day (Day 1:  FIG. 6  and Day 28:  FIG. 7 ). Results demonstrated complete inhibition of hemolysis from 2 hours after administration of the first dose through 28 days of dosing, with hemolysis percentages of &lt;5% in 1, 2, and 4 mg/kg/day groups, compared to &gt;90% in the control group. After a 28-day recovery period, sample values returned to nearly baseline hemolysis levels and little to no inhibition of the complement system was observed. The absence of complement inhibition activity at the end of the recovery period indicated clearance of the drug from the animals. 10289 Complement inhibition was also tested as part of a 13 week-repeated-dose study in the Cynomolgus monkey. Monkey samples were analyzed using the ex vivo RBC hemolysis assay. R5000 was administered daily via subcutaneous injection for 13 weeks at either 0, 0.25, 1, 2, or 10 mg/kg/day doses. Similar to the 28-day study, results from the 13-week study demonstrated complete inhibition of hemolysis ex vivo from 2 hours after administration of the first dose through 13 weeks of dosing, with hemolysis percentages of &lt;5% in 0.25, 1, 2, and 10 mg/kg/day groups, compared to &gt;90% in the control group. After a 28-day recovery period, sample values returned to nearly baseline hemolysis levels and little to no inhibition of the complement system was observed. The absence of complement inhibition activity at the end of the recovery period indicated clearance of the drug from the animals. 
     During the study, oxidative metabolism resulted in the formation and detection of a hydroxylated metabolite of R5000 with w-hydroxylation of the palmitoyl tail (referred to herein as “R5001”). 
     The ability of R5001 to inhibit complement-mediated lysis of erythrocytes via the classical complement activation pathways was tested using antibody-sensitized sheep erythrocytes in 1% normal human serum. R5001 demonstrated potent inhibition of complement-induced hemolysis with an IC 50  of 4.5 nM. 
     Example 9. Pharmacokinetic/Pharmacodynamic Modeling and Simulation of Human Pharmacokinetics 
     A PK/PD model was constructed in silico using in vivo data obtained in Cynomolgus monkeys. The model fit and accuracy were estimated by comparing simulated results to newly generated experimental data. Once validated in monkeys, the final model was used to predict human pharmacokinetics by applying allometric scaling to its parameters. The resulting simulations support a projected dosing interval of once daily or less frequently in humans, with daily doses of 0.1 mg/kg maintaining nearly 90% target inhibition at steady state (see  FIG. 8 ). Because of the long half-life of R5000, several doses are necessary to reach final peak and trough drug levels. The plasma C max  is expected to be approximately 3-fold higher following one week of daily dosing than the first dose as drug levels reach steady state. 
     Example 10. Phase 1 Single-Ascending-Dose Clinical Study of R5000 
     A Phase 1 single-ascending-dose clinical pharmacology study in healthy human volunteers designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of R5000 following subcutaneous (SC) injection was carried out. Dose volume was determined by the dose requirements of the cohort and the weight of the subject. Subjects that were pregnant or nursing as well as any subjects with systemic infection or colonization with  Neisseria meningitides  were excluded. The study was randomized, double-blinded, and placebo (PBO)-controlled with 4 SC single-ascending-dose cohorts housed in a clinical pharmacology unit for 3 days. All subjects received prophylaxis with ciprofloxacin, and subjects in the highest single-dose cohort (i.e. 0.4 mg/kg) were vaccinated against  Neisseria meningitides  at least 14 days prior to the study. All subjects received 1 dose of R5000 on Day 1. Four subjects (2 receiving R5000 and 2 receiving PBO) were administered the lowest dose level (0.05 mg/kg) and 6 subjects per cohort (4 receiving R5000 and 2 receiving PBO) were sequentially administered the 3 higher dose levels (0.1, 0.2, and 0.4 mg/kg). Subject demographic information is provided in Table 4. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Subject demographics 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 R5000 
                 R5000 
                 R5000 
                 R5000 
                   
               
               
                   
                 Placebo 
                 treated, 
                 treated, 
                 treated, 
                 treated, 
               
               
                   
                 treated, 
                 0.05 mg/kg, 
                 0.1 mg/kg, 
                 0.2 mg/kg, 
                 0.4 mg/kg, 
                 All, 
               
               
                   
                 n = 8 
                 n = 2 
                 n = 4 
                 n = 4 
                 n = 4 
                 n = 22 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Male:Female ratio 
                 2:6 
                 0:2 
                 0:4 
                 0:4 
                 1:3 
                 3:19 
               
               
                 Mean Age, 
                 39 
                 23 
                 27 
                 34 
                 32 
                 33 
               
               
                 years (min, max) 
                 (20, 59) 
                 (22, 23) 
                 (20, 37) 
                 (22, 65) 
                 (21, 58) 
                 (20, 65) 
               
               
                 Mean body mass 
                 24 
                 20 
                 21 
                 26 
                 27 
                 24 
               
               
                 index, kg/m2 
               
               
                 White:Black:Asian 
                 7:1:0 
                 2:0:0 
                 2:1:1 
                 3:0:1 
                 4:0:0 
                 18:2:2 
               
               
                   
               
            
           
         
       
     
     Safety was assessed by intensive clinical monitoring, and frequent blood samples were obtained for determination of R5000 concentrations by liquid chromatography/high resolution mass spectroscopy and ability to inhibit complement-mediated RBC lysis in an ex vivo antibody-sensitized sheep erythrocyte hemolysis assay. 
     The pharmacokinetic (PK) parameters measured in this study include clearance (CL), C max  (maximum plasma drug concentration,  FIG. 9A ), T max  (time taken to reach maximum plasma concentration following drug administration), t 1/2  (half-life), AUC 0-24  (area under the plasma concentration-time curve from time zero to 24 hours; see  FIG. 9B  for plasma concentration over time), AUC 0-inf  (area under the plasma concentration-time curve from time zero to infinity; see  FIG. 9B  for plasma concentration over time), V z  (apparent volume of distribution during terminal phase), K (elimination rate), and F(fractions). Results for each parameter are presented in Table 5. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Pharmacokinetic parameters 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 R5000 
                 R5000 
                 R5000 
                 R5000 
               
               
                 PK 
                   
                 (0.05 mg/kg) 
                 (0.10 mg/kg) 
                 (0.20 mg/kg) 
                 (0.40 mg/kg) 
               
               
                 Parameter 
                 Statistic 
                 N = 2 
                 N = 4 
                 N = 4 
                 N = 4 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 C max   
                 Mean 
                 1010 
                 (14.142) 
                 1550 
                 (197.82) 
                 2970 
                 (317.80) 
                 5873 
                 (440.71) 
               
               
                 (ng/mL) 
                 (SD) 
               
               
                 T max   
                 Median 
                 4.5 
                 (3, 6) 
                 3.0 
                 (3, 24) 
                 4.5 
                 (3, 48) 
                 4.6 
                 (3, 6) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (h) 
                 (min, max) 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 AUC 0-24   
                 Mean 
                 21440 
                 (1020.9) 
                 33230 
                 (4605.6) 
                 60350 
                 (4624.8) 
                 112300 
                 (8623.2) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (ng*h/mL) 
                 (SD) 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 AUC 0-last   
                 Mean 
                 179800 
                 (3214.7) 
                 375400 
                 (47513) 
                 655100 
                 (113710) 
                 822600 
                 (120760) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (ng*h/mL) 
                 (SD) 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 AUC 0-inf   
                 Mean 
                 190700 
                 (3081.0) 
                 408600 
                 (52716) 
                 702900 
                 (143630) 
                 863200 
                 (134870) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (ng*h/mL) 
                 (SD) 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 t 1/2   
                 Mean 
                 163.5 
                 (10.9) 
                 185.4 
                 (6.4) 
                 172.0 
                 (24.8) 
                 155.6 
                 (14.3) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (h) 
                 (SD) 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 K el  (l/h) 
                 Mean 
                 0.004248 
                 (0.000283) 
                 0.003743 
                 (0.000128) 
                 0.004092 
                 (0.00058001) 
                 0.004482 
                 (0.00041984) 
               
               
                   
                 (SD) 
               
               
                 CL/F 
                 Mean 
                 0.2622 
                 (0.0042) 
                 0.2481 
                 (0.0353) 
                 0.2933 
                 (0.0574) 
                 0.4711 
                 (0.0660) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (mL/h/kg) 
                 (SD) 
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 V Z /F 
                 Mean 
                 61.89 
                 (5.13) 
                 66.41 
                 (10.20) 
                 71.43 
                 (7.52) 
                 105.10 
                 (11.68) 
               
            
           
           
               
               
               
               
               
               
            
               
                 (mL/kg) 
                 (SD) 
               
               
                   
               
            
           
         
       
     
     All cohorts achieved C max  levels consistent with predicted values from an in silico PK model generated using data from non-human primate (NHP) studies. Plasma concentrations of a single SC injection showed a linear relationship between C max  and dose level ( FIG. 9A ) and dose-dependent exposure across all dose levels was confirmed ( FIG. 9B ). The mean maximum plasma concentration (C max ) ranged from 1010 to 5873 ng/mL across doses. The mean area under the concentration-time curve from time 0 to 24 hours post dose (AUC 0-24 ) ranged from 21,440 to 112,300 ng*h/mL across doses. These results indicate that with increasing R5000 dose, there is an approximately proportional increase in plasma concentration (C max ) and exposure (AUC 0-24 ). The median time to maximum observed plasma concentration (t max ) ranged from 3.0 to 4.6 hours across doses indicating R5000 exhibits an intermediate rate of absorption from the SC space to the central (blood) compartment. The mean apparent total body clearance (CL/F) after R5000 administration was low and ranged from 0.2481 to 0.4711 mL/h/kg. The mean half-life (t 1/2 ) was consistent across dose levels and ranged from 155.6 to 185.4 hours. The mean apparent total volume of distribution (V z /F) at the terminal phase after extravascular administration ranged from 61.89 to 105.1 mL/kg which indicates R5000 is localized primarily in the circulating blood compartment with minimal extravascular distribution. The approximate t 1/2  across all cohorts was determined to be 7 days. 
     R5000 also exhibited a rapid dose-dependent inhibition of hemolysis [direct hemolysis ( FIG. 10A ) and % CH 50  ( FIG. 10B ) and red blood cell lysis at 1% plasma over time ( FIG. 10C )] and suppression of complement activity (as determined by WIESLAB® ELISA in all subjects after a single dose, see  FIG. 11 ). The maximum pharmacodynamics effect was observed approximately 3 hours after dosing. Results demonstrated that at the maximum plasma concentration, the maximal percent inhibition of hemolysis compared to baseline reached &gt;90% for the 0.1, 0.2, and 0.4 mg/kg dose cohorts and 60% for the lowest dose (0.05 mg/kg) cohort. Dose-dependent inhibition of hemolysis of up to 4 days was observed for the 0.1, 0.2, and 0.4 mg/kg dose cohorts. Notably, mean hemolysis remained above baseline for up to 2 days in the 0.05 mg/kg cohort, up to 4 days in the 0.1 mg/kg cohort, and for up to 7 days in the 0.2 and 0.4 mg/kg cohorts. 
     Similarly, analysis of complement activity demonstrated that inhibition of complement activity remained strong over the course of 4 days following the 0.4 mg/kg injection (see  FIG. 11 ). Human plasma samples taken from subjects receiving 0.4 mg/kg injection were subjected to WIESLAB® ELISA (Euro Diagnostica, Malmo, Sweden) analysis. This assay measures the alternative pathway of complement activity. As measured via this assay, complement activity was suppressed to 3% at 3 hours following dosing and remained below 13% 96 hours after receiving R5000. 
     Single SC doses of R5000 were safe and well tolerated in healthy volunteers. No clinically significant changes were observed in vital signs, clinical laboratory parameters, physical exams, and ECGs. 
     This study suggests that low daily doses may achieve steady-state levels suitable for &gt;80% suppression of hemolysis and that once-weekly dosing may be sufficient. Specifically, 0.2 mg/kg may result in full suppression of complement activity and complete inhibition of hemolysis. 
     Example 11. Multiple-Dose Clinical Study of R5000 
     A Phase 1 multiple-dose clinical pharmacology study in healthy human volunteers designed to evaluate the safety, tolerability, pharmacokinetics and pharmacokinetics and pharmacodynamics of R5000 following once daily subcutaneous (SC) injections over 7 was carried out. The study was single-center, randomized, double-blinded, and placebo (PBO)-controlled. Subjects received daily SC doses of 0.2 mg/kg R5000 or matching PBO for 7 days while housed in a clinical pharmacology unit. Dose volume was determined by the dose requirements of the cohort and the weight of the subject. Subjects that were pregnant or nursing as well as any subjects with systemic infection or colonization with  Neisseria meningitides  were excluded. All subjects received prophylaxis with ciprofloxacin, and subjects in the multiple-dose cohort were vaccinated against  Neisseria meningitides  at least 14 days prior to the study. Safety was assessed by intensive clinical monitoring and daily blood samples were obtained immediately prior to dosing as well as, 3 hours, and 6 hours after each day&#39;s dose for determination of R5000 concentrations by liquid chromatography/high resolution mass spectroscopy and ability to inhibit complement-mediated RBC lysis in an ex vivo antibody-sensitized sheep erythrocyte hemolysis assay. 
     A total of 6 subjects were enrolled into the study (4 receiving R5000 and 2 receiving PBO). Subject demographics are presented in the Table 6. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Subject demographics 
               
            
           
           
               
               
               
            
               
                   
                 Placebo treated, 
                 R5000 treated, 
               
               
                   
                 n = 2 
                 n = 4 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                 Male:Female ratio 
                 0:2 
                 1:3 
               
               
                 Mean Age, years (min, max) 
                 27 (25, 29) 
                 24 (22, 26) 
               
               
                 Mean body mass index, kg/m 2   
                 21 
                 23 
               
               
                 White:Asian 
                 2:0 
                 3:1 
               
               
                   
               
            
           
         
       
     
     As seen in Table 7 and related  FIG. 12A  (demonstrating percent hemolysis and plasma concentration over 7 days), plasma concentrations showed a steadily increasing exposure over the 7 days of dosing. From these data, the half-life of R5000 was determined to be 7 days. Plasma levels returned to around 2000 ng/ml by day 15 and around 1000 ng/ml by day 21 ( FIG. 12B ). 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Plasma concentrations of R5000 
               
            
           
           
               
               
            
               
                 Time Point 
                 Concentration of R5000 (ng/ml) 
               
            
           
           
               
               
               
               
               
            
               
                 (hrs) 
                 Subject 1 
                 Subject 2 
                 Subject 3 
                 Subject 4 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                 3 
                 2510 
                 2410 
                 2560 
                 2520 
               
               
                 6 
                 2300 
                 2390 
                 2410 
                 2650 
               
               
                 24 
                 1890 
                 1750 
                 1810 
                 2220 
               
               
                 27 
                 3870 
                 4050 
                 4280 
                 4110 
               
               
                 30 
                 3650 
                 3730 
                 4310 
                 4000 
               
               
                 48 
                 2910 
                 2650 
                 3370 
                 3330 
               
               
                 51 
                 5200 
                 4910 
                 5330 
                 5500 
               
               
                 54 
                 4820 
                 4220 
                 5100 
                 4900 
               
               
                 72 
                 3680 
                 3340 
                 3780 
                 4460 
               
               
                 75 
                 6310 
                 5240 
                 5280 
                 6110 
               
               
                 78 
                 5720 
                 5570 
                 5880 
                 6140 
               
               
                 96 
                 4650 
                 3790 
                 4840 
                 4540 
               
               
                 99 
                 6660 
                 5320 
                 6860 
                 6770 
               
               
                 102 
                 7000 
                 5440 
                 6550 
                 6820 
               
               
                 120 
                 4840 
                 4430 
                 5200 
                 5280 
               
               
                 123 
                 7210 
                 6410 
                 7210 
                 7700 
               
               
                 126 
                 7290 
                 5850 
                 6880 
                 7020 
               
               
                 144 
                 5170 
                 4210 
                 4920 
                 5430 
               
               
                 147 
                 7430 
                 6320 
                 7490 
                 7780 
               
               
                 150 
                 6920 
                 6130 
                 7630 
                 7110 
               
               
                 168 
                 5750 
                 4940 
                 5730 
                 5670 
               
               
                   
               
            
           
         
       
     
     The PK parameters of R5000 following multiple dose SC administration (0.2 mg/kg/day) for 7-days are presented in Table 8. The pharmacokinetic (PK) parameters measured include clearance (CL), C max  (maximum plasma drug concentration), T max  (time taken to reach maximum plasma concentration following drug administration), t 1/2  (half-life), AUC tau  (area under the plasma concentration-time curve from time zero to 24 hours), AUC 0-inf  (area under the plasma concentration-time curve from time zero to infinity), V z /F (apparent volume of distribution), K el  (elimination rate), and F (fractions). 
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Summary of PK parameters 
               
            
           
           
               
               
            
               
                 PK 
                 R5000 (0.20 mg/kg) (N = 4) 
               
            
           
           
               
               
               
               
            
               
                 Parameter 
                 Statistic 
                 Day 1 
                 Day 7 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Cmax 
                 Mean 
                 2533 
                 (100.1) 
                 7290 
                 (662.4) 
               
               
                 (ng/mL) 
                 (SD) 
               
               
                 T max   
                 Median 
                 3 
                 (3, 6) 
                 3 
                 (3, 6) 
               
               
                 (h) 
                 (min, 
               
               
                   
                 max) 
               
               
                 AUC tau   
                 Mean 
                 50010 
                 (3334.0) 
                 151300 
                 (12042) 
               
               
                 (ng*h/mL) 
                 (SD) 
               
            
           
           
               
               
               
               
               
            
               
                 AUC0-inf 
                 Mean 
                 NC 
                 1101000 
                 (108220) 
               
               
                 (ng*h/mL) 
                 (SD) 
               
               
                 t 1/2   
                 Mean 
                 NC 
                 161.9 
                 (14.8) 
               
               
                 (h) 
                 (SD) 
               
               
                 K el  (1/h) 
                 Mean 
                 NC 
                 0.004309 
                 (0.00041325) 
               
               
                   
                 (SD) 
               
               
                 CL/F 
                 Mean 
                 NC 
                 1.330 
                 (0.114) 
               
               
                 (mL/h/kg) 
                 (SD) 
               
               
                 V Z /F 
                 Mean 
                 NC 
                 311.6 
                 (51.4) 
               
               
                 (mL/kg) 
                 (SD) 
               
               
                   
               
            
           
         
       
     
     The day 1 mean C max  and AUC tau  were 2533 ng/mL and 50,010 ng*h/mL respectively, consistent with results from the 0.2 mg/kg single-dose cohort over the same post-dose period. Following daily SC administration for 7 days, the C max  and AUC tau  increased by approximately 2.9-fold (mean day 7 C max =7290 ng/mL) and 3.0-fold (mean day 7 AUC tau =151,300 ng*h/mL) respectively. The median time to maximum plasma concentration (T max ) on day 7 was 3.0 hours, which was consistent with the T max  following single dose SC administration (median day 1 T max =3.0-4.6 hours). This indicates a consistent rate of R5000 absorption with repeat dosing. The mean day 7 apparent total body clearance of R5000 (day 7 CL/F=1.3 mL/h/kg) was slightly increased relative to the total body clearance following a single SC dose at 0.2 mg/kg [single ascending dose (SAD) 0.2 mg/kg CL/F=0.29 mL/h/kg]. However, the elimination rate constant (Kei) for R5000 was consistent following single and repeat dosing (0.2 mg/kg SAD mean K el =0.0041 h −1 ; 0.2 mg/kg MD mean day 7 K el =0.0043 h +1 ) indicating that the clearance of R5000 does not change significantly with repeat dosing. The apparent volume of distribution of R5000 (V z /F) showed some increase with administration of multiple doses of R5000 (0.2 mg/kg SAD mean V z /F=71.4 mL/kg; 0.2 mg/kg MD mean day 7 V z /F=311.6 mL/kg). However, the day 7 V z /F for R5000 was still less than total body water suggesting that R5000 did not distribute into the extravascular space upon repeat SC administration. 
     Mean percent inhibition of hemolysis was measured in subject serum samples to determine whether low daily doses are suitable to achieve steady-state levels and complete and sustained inhibition of complement and suppression of hemolysis (see Table 9). 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Hemolysis analysis 
               
            
           
           
               
               
               
            
               
                 Time 
                 % Hemolysis (treated) 
                 % Hemolysis (placebo) 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Point 
                 Sub- 
                 Sub- 
                 Sub- 
                 Sub- 
                 Sub- 
                 Sub- 
               
               
                 (hrs) 
                 ject 1 
                 ject 2 
                 ject 3 
                 ject 4 
                 ject 5 
                 ject 6 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0 
                 100.0 
                 100.0 
                 100.0 
                 100.0 
                 100.0 
                 100.0 
               
               
                 3 
                 5.8 
                 1.9 
                 5.0 
                 2.9 
                 99.4 
                 102.7 
               
               
                 6 
                 6.0 
                 1.6 
                 5.2 
                 2.3 
                 90.8 
                 99.4 
               
               
                 24 
                 9.3 
                 2.4 
                 8.9 
                 2.9 
                 105.8 
                 100.7 
               
               
                 27 
                 4.9 
                 1.2 
                 4.0 
                 1.0 
                 112.3 
                 96.1 
               
               
                 30 
                 4.6 
                 1.5 
                 4.6 
                 2.2 
                 110.5 
                 100.6 
               
               
                 48 
                 6.6 
                 2.0 
                 6.9 
                 2.1 
                 120.6 
                 107.2 
               
               
                 51 
                 4.0 
                 1.4 
                 3.6 
                 1.9 
                 118.4 
                 97.3 
               
               
                 54 
                 3.7 
                 1.4 
                 3.6 
                 1.8 
                 133.5 
                 98.0 
               
               
                 72 
                 5.0 
                 1.6 
                 3.8 
                 1.7 
                 114.4 
                 97.9 
               
               
                 75 
                 2.9 
                 0.8 
                 2.7 
                 1.3 
                 121.4 
                 98.2 
               
               
                 78 
                 3.0 
                 0.9 
                 4.7 
                 1.5 
                 119.4 
                 94.6 
               
               
                 96 
                 3.9 
                 1.1 
                 4.0 
                 6.5 
                 111.5 
                 95.2 
               
               
                 99 
                 2.9 
                 0.9 
                 2.7 
                 1.0 
                 122.0 
                 101.1 
               
               
                 102 
                 3.6 
                 1.4 
                 3.8 
                 1.7 
                 135.1 
                 101.4 
               
               
                 120 
                 4.0 
                 2.1 
                 3.8 
                 2.3 
                 115.4 
                 95.7 
               
               
                 123 
                 2.7 
                 1.3 
                 2.7 
                 1.6 
                 114.1 
                 92.2 
               
               
                 126 
                 3.3 
                 1.3 
                 3.2 
                 1.3 
                 113.5 
                 96.9 
               
               
                 144 
                 3.4 
                 1.2 
                 3.8 
                 1.4 
                 108.8 
                 95.7 
               
               
                 147 
                 2.5 
                 1.2 
                 2.6 
                 1.2 
                 121.7 
                 103.7 
               
               
                 150 
                 3.4 
                 1.3 
                 3.0 
                 1.4 
                 121.3 
                 98.3 
               
               
                 168 
                 3.4 
                 1.5 
                 3.1 
                 1.8 
                 119.1 
                 102.0 
               
               
                   
               
            
           
         
       
     
     Mean percent inhibition of hemolysis compared to baseline reached ≥95% beginning at the first time point following dosing, 3 hours after dosing on Day 1, and continued throughout the 7 days of dosing. All individual subjects showed ≥90% reduction of hemolysis at all time points. Hemolysis at day 8 (24 hours after receiving the last dose) was observed to be ≤3% in all subjects. Hemolysis returned to pre-dose levels within two weeks following the last dose. 
     The study suggests that low daily doses will achieve steady-state levels suitable for complete and sustained inhibition of complement and suppression of hemolysis. The study also suggests that once-weekly dosing may be sufficient to inhibit complement activity and reduce hemolysis in humans. 
     Complement activity in subject plasma samples was determined by WIESLAB® ELISA (Euro Diagnostica, Malmo, Sweden) analysis. This assay measures the alternative pathway of complement activation. As measured via this assay, suppression of complement activity was rapid, complete, and sustained across the dosing period in all subjects (see  FIG. 13A  and Table 10). In the Table, SEM indicates standard error of the mean. 
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 % complement activity in multiple dose study 
               
            
           
           
               
               
               
            
               
                   
                 Hours after first treatment 
                   
               
            
           
           
               
               
               
               
            
               
                   
                 3 
                 48 
                 96 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                 Minimum % complement 
                 1.8 (0.8) 
                 6.9 (0.3) 
                 2.1 (0.1) 
               
               
                 activity (SEM) 
               
               
                 Average % complement 
                 3.1 (0.6) 
                 8.2 (1.1) 
                 3.1 (0.8) 
               
               
                 activity (SEM) 
               
               
                   
               
            
           
         
       
     
     Complement activity at day 8 (24 hours after the last dose) was observed to be ≤5% in all subjects. Complement activity returned to pre-dose levels within two weeks following the last dose ( FIG. 13B ). 
     R5000 was safe and well-tolerated in healthy volunteers. No clinically significant changes were observed in vital signs, clinical laboratory parameters (hematology, blood chemistry, coagulation, and urinalysis), physical exams and ECGs. 
     R5000 and metabolite R5001 were measured in the 0.20 mg/kg dose group of the multi-dose arm of the study, and both were detected. 
     Example 12. Pharmacokinetic/Pharmacodynamic Modeling and Simulation of Human Pharmacokinetics for Phase II Study 
     A PK/PD model was developed to describe plasma concentrations of R5000 and its metabolites, and their activity in an ex vivo red blood cell lysis assay. The model was based on a quasi-steady-state approximation of the target-mediated drug disposition model. In the multi-dose arm of the Phase I study with R5000, all subjects achieved drug levels consistent with predicted values from the in silico PK model generated using single-dose human PK and PD data. Human PK/PD simulations of R5000 support a projected dosing regimen of a 0.3 mg/kg loading dose followed by daily doses of 0.1 mg/kg yielding ≥90% target inhibition after the first dose and at steady state ( FIG. 14 ). 
     Example 13. Phase II Clinical Trial Study Design 
     A 0.1 mg/kg/day dose of R5000 was selected based on the predicted steady state drug levels for the nominal as well as the maximum dose (based on weight bracketing). Results are presented in Table 11. In the Table, C max  refers to maximum plasma drug concentration, AUC 0-24  indicates area under the plasma concentration-time curve from time zero to 24 hours, SD indicates single dose, QD indicates once daily dose, and * adjacent to maximum dose indicates the potential maximum dose received by patients due to weight bracketed dosing. 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 Experimental and predicted PK values 
               
            
           
           
               
               
            
               
                   
                 R5000 (0.1 mg/kg) 
               
               
                   
                 Steady State 
               
            
           
           
               
               
               
            
               
                   
                 R5000 
                 Prediction in Human 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 (0.2 mg/kg) 
                 Nominal 
                 Maximum 
               
               
                   
                   
                 QDx7; Day 
                 (Minimal) 
                 dose* 
               
               
                 Pharmacokinetic 
                 Sta- 
                 7 Human 
                 0.1 mg/kg 
                 0.14 mg/kg 
               
               
                 Parameter 
                 tistic 
                 (SD) 
                 once daily 
                 once daily 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 C max  (μg/mL) 
                 Mean 
                 7.29 
                 (0.66) 
                 6.57 
                 7.12 
               
               
                 AUC 0-24   
                 Mean 
                 151.3 
                 (12) 
                 141.5 
                 152.8 
               
               
                 (h*μg/mL) 
               
               
                   
               
            
           
         
       
     
     The inhibition of hemolysis was expected to be maintained at ≥90% at all times with a daily dose of 0.1 mg/kg R5000 and a loading dose of 0.3 mg/kg R5000 administered on the first day of dosing based on Phase I studies. This prediction was supported by overlaying the expected R5000 plasma concentrations at steady state, with the PK/PD relationship obtained from Phase 1 studies in healthy volunteers ( FIG. 15 ). Adequate and sustained control of hemolysis is a key component of both efficacy and safety in treating paroxysmal nocturnal hemoglobinuria (PNH). In this disease, even a modest transient decrease in complement blockade can lead to immediate “breakthrough” intravascular hemolysis and recrudescence of severe PNH symptoms. This consideration was particularly important with respect to accounting for the potential for missed doses. 
     In order to achieve and maintain hemolysis control efficiently, the Phase 2 studies were designed to incorporate a single loading dose of 0.3 mg/kg to adequately suppress hemolysis after the first dose. Well tolerated single doses of up to 0.4 mg/kg sub cutaneous injections in the single dose cohorts of the Phase 1 study in healthy volunteers ( FIG. 16A ) provided the rationale for the use of a 0.3 mg/kg loading dose after overlaying the expected R5000 plasma trough concentrations after the first dose, with the PK/PD relationship obtained from Phase 1 studies in healthy volunteers. The loading dose was not expected to impact expected exposures at steady state. A loading dose of 0.3 mg/kg was predicted to achieve the target pharmacodynamic effect (&gt;90% hemolysis inhibition) at trough levels, to facilitate immediate control of hemolysis after the first dose (see the PK/PD model presented in  FIG. 16B ). Based on the PK/PD model, if, after reaching steady state a subject misses a dose, the proposed starting dose regimen was expected to maintain inhibition of hemolysis at ≥90% for at least 72 hours (see the model presented in  FIG. 16C ). 
     From the Week 2 visit onwards, subjects not achieving an adequate response (defined as a lactate dehydrogenase level that is 1.5 times less than the upper limit normal), and following evaluation of safety and tolerability data by the investigator and the medical monitor, the dose was planned to be escalated to 0.3 mg/kg daily. The dose was planned to be escalated to 0.3 mg/kg daily if an overt breakthrough hemolysis episode (e.g., hemoglobinuria) was observed. 
     Example 14. Phase II Study Dose, Administration and Contraindications 
     During Phase II clinical studies, R5000 is administered once daily (every 24 hours) by SC self administration at a dose of 0.1 mg/kg following an initial loading dose of 0.3 mg/kg on the first day of dosing (Study Day 1). Some subjects may receive a higher dose of 0.3 mg/kg to optimize control of hemolysis. The dose (dose volume) for each injection is determined based on the dose assigned and patient body weight. It is not anticipated that overdose of R5000 will lead to acute or specific systemic adverse events. In case of overdose, clinically appropriate supportive measures are instituted as determined by the clinical scenario, and in consultation with a medical monitor. 
     R5000 daily dosing has the potential to achieve consistent and sustained inhibition of complement, and therefore reduce the risk of breakthrough hemolysis. The dosing regimen of R5000 is selected to avoid a large peak to trough ratio in plasma concentration, as is seen with monoclonal antibodies administered every two weeks. With an approximate plasma half-life of 7 days, R5000 administered daily is expected to remain within a narrow plasma concentration range, effectively “clamping” terminal complement activity under continuous inhibition and avoiding the phenomenon of “breakthrough hemolysis”. 
     This is in contrast to the current standard of care, eculizumab. A proportion of patients receiving eculizumab are reported to have inadequate control of their disease which results in breakthrough hemolysis occurring near the end of the 2-week dosing interval using the approved dose of 900 mg biweekly (Hillmen P, et al. Long-term safety and efficacy of sustained eculizumab treatment in patients with paroxysmal nocturnal haemoglobinuria. Br J Haematol 2013; 162:62-73 and Brodsky R A. Paroxysmal nocturnal hemoglobinuria. Blood 2014; 124:2804-2811). The clinically approved treatment schedule of eculizumab is biweekly, i.e. once every 12-16 days. While hemolysis is well controlled within the first days of the treatment cycle, efficacy is often reduced, as plasma levels of eculizumab fade in the last days before re-administration. This lack of disease control while on eculizumab has resulted in a need to increase doses above the authorized dose, for which no clinical trials have been performed to establish safety or efficacy. The United Kingdom (UK) PNH National Service Reports shows that nearly 22% of patients treated with eculizumab require non-standard doses due to breakthrough hemolysis at the standard dose. 
     Subjects are instructed to self-administer SC doses daily every 24 hours at approximately the same time each day. Subjects are directed to inject in the abdomen, however injections to the thigh or upper arm may be used. In the study, subjects are required to document daily confirmation of dosing and the location of the injection. The currently available therapy, eculizumab, requires intravenous infusions to be administered every 2 weeks under medical supervision. In contrast, R5000 has been developed for subcutaneous self-administration at home, and thus is a convenient therapy format for patients. 
     Subjects who have hypersensitivity to R5000 or any of its excipients do not receive treatment with R5000. Subjects with colonization, or unresolved or suspected infection with  Neisseria meningitides  are also prohibited from treatment with R5000. 
     Example 15. Safety Assessment in R5000 Phase II Clinical Trial 
     The clinical study includes safety assessments to monitor adverse events (including injection reactions and systemic infection), clinical laboratory tests (including markers for liver and pancreatic function), ECG, vital signs, and physical examinations. The Phase II studies incorporate frequent monitoring visits with clinic visits scheduled weekly for the first 4 weeks, followed by every 2 weeks thereafter. The long-term extension study includes continued monitoring with clinic visits monthly for the first 3 months, and every 3 months thereafter, with monitoring and clinic visits expected to continue to accrue long-term safety and tolerability data. 
     Example 16. Inhibition of Hemolysis Using R5000-Related Peptides with Red Blood Cells Non-Responsive to Eculizumab Due to C5 Mutation 
     Blood/plasma samples from two Japanese PNH patients who had a poor response to eculizumab were analyzed. Both patients were previously shown to possess a single missense C5 heterozygous mutation, c.2654G-&gt;A, which predicts the polymorphism p.Arg885His (for a description of this polymorphism, see Nishimura, J. et al., N Engl J Med. 2014. 370(7):632-9, the contents of which are herein incorporated by reference in their entirety). In the study, mR5000 was tested on patient serum samples. mR5000 is identical to R5000, except the C-terminal lysine is unmodified. Compound mR5000 has similar anti-hemolytic activity to that of R5000, but a shorter half life when administered to a subject. Patient serum was acidified and mixed with RBCs in the presence (+) or absence (−) of mR5000. Complete inhibition of hemolysis was observed in the presence of mR5000 ( FIG. 17 ). 
     Example 17. R5000 Treatment in Patients Who are not Responsive to Eculizumab 
     Based on the distinct binding site of R5000, R5000 is used for treatment of PNH in patients with mutations in the C5 gene that prevent binding of eculizumab to C5. R5000 binds to a distinct site on C5 compared with eculizumab and can therefore prevent C5 activation in patients who are non-responsive to eculizumab due to mutations near its binding site on C5. 
     Example 18. Comparison Between R5000 and Antibody-Based C5 Inhibitors 
     Inhibition of complement activity was evaluated by hemolysis of rabbit or PNH patient erythrocytes, and by measuring generation of C5a and C5b-9 by ELISA. C5 and C5-eculizumab complex levels were measured in PNH patient samples with ELISAs using a C5-binding reagent to capture C5 or the complex and detecting with either an anti-C5 antibody followed by an HRP-conjugated secondary antibody (total C5) or using an HRP-conjugated secondary to detect eculizumab (C5-eculizumab complex). Inhibition of C5 binding to the alternative pathway (AP) C5 convertase was measured by SPR. 
     Residual hemolytic activity has been shown to exist after treatment with eculizumab (see Brodsky et al., 2017. Blood 129; 922-923 and Harder et al., 2017. Blood. 129:970-980). R5000 completely inhibited complement activity in several in vitro assays where residual hemolysis was evident with eculizumab (Alexion Pharmaceuticals, New Haven, Conn.), including hemolytic activity and generation of C5a and C5b-9. In serum from a PNH patient treated with eculizumab, approximately 30% of the hemolytic activity of normal human serum was retained in a rabbit erythrocyte lysis assay even with the addition of excess eculizumab (up to 12.5 μM). Addition of R5000 completely abolished this residual hemolytic activity. Finally, R5000 completely inhibited C5 binding to the AP C5 convertase, as determined by SPR, while eculizumab only partially inhibited C5 binding. Overall, these results suggest that the mechanism of inhibition of R5000 promotes complete inhibition of hemolysis under conditions where eculizumab yields partial inhibition. 
     Example 19. Cohort a Results in Two Patients at Week 7 
     A dose-finding study to evaluate the safety, tolerability, preliminary efficacy, pharmacokinetics, and pharmacodynamics of R5000 was carried out in patients with PNH. The study was an open-label 12 week study with long-term extension. The study program was conducted globally and designed to address 3 PNH populations: (Cohort A) eculizumab naïve subjects; (Cohort B) subjects being switched from eculizumab to R5000; and (Cohort C) subjects with inadequate response to eculizumab. Patients received R5000 by subcutaneous injection with a loading dose of 0.3 mg/kg on Day 1 followed by a daily dose of 0.1 mg/kg for the first two weeks. From the week 2 visit onward, where the lactate dehydrogenase (LDH) level was equal to or greater than 1.5 times the upper limit normal, the daily dose could be increased to 0.3 mg/kg. A primary efficacy endpoint of the study was to achieve a change in LDH level from baseline to the mean level from week 6 to week 12 of the study. 
     Near-complete inhibition of hemolytic activity at week 7 was achieved in two patients (patient 001 and patient 002) in Cohort A with 100% compliance (no dosing interruptions, monitored remotely using a remote monitoring device) with the treatment regimen. Percent hemolysis and hemoglobin levels at each time point are shown in  FIG. 18A  and  FIG. 18B , respectively. Patient 001 was a 56-year old female diagnosed with PNH in April of 2007. Patient 001 had a granulocyte clone size of 80% and an RBC clone size of 25% and received no transfusions prior to enrollment. Patient 002 was a 65-year old female diagnosed with PNH in April of 2017. Patient 002 had a granulocyte clone size of 99% and an RBC clone size of 47%. Patient 002 was transfusion-dependent prior to enrollment and received transfusion at weeks 4 and 6 of the study. Rapid declines in LDH were observed in both patients and mean LDH at week 7 was 1.55 times the upper limit normal ( FIG. 18C ). R5000 levels remained relatively stable through week 6 ( FIG. 18D ). One transient episode of breakthrough hemolysis associated with inter-current illness was observed. No safety or tolerability concerns were identified. No serious or related adverse events were observed and no injection site reactions were observed. 
     Example 20. Surface Plasmon Resonance (SPR) Measurement of C5 Inhibitor Binding 
     Binding of R5000 and eculizumab to alternative pathway C5-convertase was examined by Surface Plasmon Resonance (SPR) analysis. SPR measurements were performed at 25° C. on a ProteOn XPR36 SPR station (Bio-Rad, Hercules, Calif.). Eculizumab was immobilized at pH 4.5 of 10 mM sodium acetate to a Bio-Rad GLH sensor chip via amine coupling (NHS/EDC coupling kit from Bio-Rad) and blocked with ethanolamine (Bio-Rad) at 25° C. Biotinylated R5000 was separately captured to a Bio-Rad NLC sensor chip. Kinetic/affinity data of C5 binding for Eculizumab and R5000 were separately performed by flowing serial diluted C5 (Complement Technologies, TX) to the surfaces of eculizumab or R5000. The same running/assay buffer (10 mM potassium phosphate pH 7.4 and 6.0, 150 mM NaCl, 1% DMSO, and 0.01% Surfactant P-20) were used throughout. Surface regeneration was achieved using one injection of 10 mM Glycine (pH 1.5) followed by flowing of the running buffer. Data analysis (affinity and kinetic parameters) were conducted using a 1:1 Langmuir mode. 
     Biotinylated human complement component C3b (Complement Technologies, TX) was prepared by mixing EZ-link maleimide-PEG2-biotin (Thermo Fisher Scientific, Waltham, Mass.) with C3b stock according to the provider&#39;s protocol. Unused biotin was separated from biotinylated C3b through desalting column. Biotinylated C3b was captured on a Bio-Rad NLC sensor chip according to the standard protocol. To assemble alternative pathway (AP) C5-convertase on captured C3b surface, serial injections of human complement components (all purchased from Complement Technologies, Tyler, Tex.) were conducted by using a co-injection mode. The co-injection mode included a first injection of a premixed factor B (fB; 150 nM) and factor D (fD; 10 nM) (25 μl/min for 60 s), followed by 500 nM C3 (25 μl/min for 120 s), then C5 (400 nM) alone or mixed with serially diluted R5000 or eculizumab (25 μl/min for 60 s). The dissociation time was 360 s. All assays were done at 37° C. in 10 mM HEPES pH 7.4, 150 mM NaCl, 1% DMSO, and 0.01% Surfactant P-20. To quantitatively analyze C5 binding at different inhibitor concentrations, individual SPR sensorgrams after injection of C5 were normalized to the time point of C5 injection, and fractions of SPR signal were calculated. Results demonstrated decreased binding of C5 to the AP C5-convertase in the presence of R5000 and eculizumab (as evidenced by decreased response to C5, see  FIG. 19 ), with 2 μM R5000 having a stronger effect. 
     Example 21. Inhibition of PNH Patient Erythrocyte Hemolysis 
     Inhibition of hemolysis in erythrocytes from PNH patients was assessed in the presence or absence of R5000 and eculizumab. Erythrocytes were collected from PNH patient blood samples by centrifugation at 1000×g for 3 minutes to pellet, and washed 3 times with Alsever&#39;s solution. The cell pellet was resuspended 1:2 in GVB ++  buffer (Complement Technology, Tyler, Tex.). Donor-matched normal human sera was acidified to pH 6.4 by addition of HCl. PNH patient erythrocytes (2.5% v/v) were incubated in a clear 96-well assay plate with 50% acidified donor-matched serum and indicated concentrations of compounds for 18 hours at 37° C. Cells were then centrifuged at 1000×g for 3 minutes and 100 μl of the supernatant transferred to a separate clear 96-well assay plate for detection of absorbance at 412 nm. 
     The results from two patients shown in  FIG. 20  and  FIG. 21  respectively, demonstrate that R5000 completely blocks hemolysis of PNH patient erythrocytes, while eculizumab partially inhibits hemolysis. Recombinant C5 containing a known polymorphism p.Arg885His, which confers resistance to eculizumab, was used as the only source of C5 in an alternative pathway hemolysis assay, using C5 depleted serum and rabbit erythrocytes. Increasing concentrations of R5000 or eculizumab were tested in the assay to evaluate their ability to inhibit hemolysis (see  FIG. 22 ). The results demonstrate that R5000 is capable of binding and inhibiting hemolysis mediated by C5 p.Arg885His, while eculizumab is ineffective. 
     Example 22. Measurement of C5, Eculizumab, and C5/Eculizumab Complex Levels in PNH Patient Plasma 
     C5, eculizumab and C5/eculizumab complex levels in PNH patient plasma were measured by one of three ELISA formats, each using a variant of R5000 as a capture agent. The R5000 assay variant included an N-terminal biotinylated PEG moiety and substitution of the modified C-terminal lysine residue with norvaline. 5 pmol per well of the R5000 variant was immobilized on a NeutrAvidin coated 96-well microplate (Thermo Fisher Scientific, Waltham, Mass.) to serve as a capture agent for C5. Immobilization was carried out in assay buffer (25 mM Tris-HCl, 150 mM NaCl, 0.05% Tween-20 and 1 mg/mL BSA) for 2 hours at room temperature, then washed 3 times with assay buffer. 
     For detection of total C5, plasma was diluted 1:10,000 fold in assay buffer and 100 was added to assay plate wells. C5 standards were prepared (3-fold serial dilution in assay buffer starting from 100 ng/mL) and added to assay plate wells. The plate was incubated at room temperature for 1 hour and washed 5 times with assay buffer. Eculizumab (1 μg/mL in assay buffer) was then added to each well and incubated for 1 hour at room temperature to bind any C5 in the sample that was not already complexed with eculizumab. Horse radish peroxidase (HRP)-conjugated goat anti-human IgG (Abcam, Cambridge, UK; 1:5000 dilution) was added as a secondary antibody to detect eculizumab bound to C5 and incubated for 30 minutes at room temperature. TMB substrate (UltraTMB ELISA, Thermo Fisher Scientific) was then added to the plate and incubated for 30 minutes. The reaction was stopped with 2N sulfuric acid solution, and absorbance read on a SPECTRAMAX® M3 plate reader (Molecular Devices, Sunnyvale, Calif.) at 450 nm. The amount of total C5 was calculated relative to the C5 standard curve. 
     Detection of C5/eculizumab complex level was performed using the same method as described above but without addition of excess eculizumab. This assay used diluted pre-mixed C5/eculizumab complex (1:1 molar ratio, 3-fold serial dilution starting from 100 ng/mL) as a standard. 
     To measure free eculizumab, 100 μl of a 1 μg/ml solution of C5 in assay buffer was added to the assay plate coated with C5 binding peptide and incubated for 1 hour at room temperature. Patient plasma diluted 1:10,000 in assay buffer was added to test wells and diluted eculizumab (3-fold serial dilution starting from 100 ng/mL) was used as a standard. 
     The concentration of total C5, eculizumab-bound C5, and free eculizumab detected in samples from PNH patients treated with eculizumab or from normal human serum are presented in  FIG. 23 . These results demonstrate the presence of sufficient eculizumab in a PNH patient sample to saturate C5 and form C5:eculizumab complexes. 
     Example 23. Effect of R5000 on Residual Hemolysis in Eculizumab-Treated PNH Patient Plasma 
     Hemolytic activity of plasma from a patient treated with eculizumab was tested in the presence of additional eculizumab and C5 inhibitor peptide (R5000) in an assay designed to detect activation of the alternative pathway. Rabbit erythrocytes (Ers; #B302; Complement Technology Inc., Tyler, Tex.) were incubated with 25% eculizumab-treated patient plasma in the presence of MgEGTA (B106; Complement Technology Inc., Tyler, Tex.), complement inhibitors at 12.5 μM, 4.204 and 1.4 μM, and assay buffer (GVB°; #B101; Complement Technology Inc., Tyler, Tex.) for 30 minutes at 37° C. in a 96-well clear assay plate. Following incubation, the plate was centrifuged at 1000×g and 100 μL of supernatant was transferred to a new 96-well clear assay plate and the absorbance at 412 nm was measured. Absorbance values were normalized to a plate control of 25% (final concentration) normal human sera (#NHS; Complement Technology Inc., Tyler, Tex.) which was set to 100% hemolysis. 
     Results shown in  FIG. 24 , suggest that even in the presence of enough eculizumab to bind to all available C5 in the patient sample, there is still sufficient activation of the alternative complement pathway to induce hemolysis of rabbit erythrocytes. Treatment with additional eculizumab provided only modest inhibition of hemolysis, confirming that the hemolytic activity is not due to insufficient eculizumab in the sample. However, addition of R5000 completely abolished the residual hemolytic activity, demonstrating that the residual activity is C5-dependent and suggesting that R5000 can further inhibit hemolysis in the presence of excess eculizumab.