Pegvaliase

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# Black Box Warning

# Overview
Pegvaliase is a phenylalanine-metabolizing enzyme that is FDA approved for the reduction of blood phenylalanine concentrations in adult patients with phenylketonuria who have uncontrolled blood phenylalanine concentrations greater than 600 micromol/L on existing management. There is a Black Box Warning for this drug as shown here.  Common adverse reactions include injection site reactions, arthralgia, hypersensitivity reactions, headache, generalized skin reactions lasting at least 14 days, pruritus, nausea, abdominal pain, oropharyngeal pain, vomiting, cough, diarrhea, and fatigue.

# Adult Indications and Dosage

## FDA-Labeled Indications and Dosage (Adult)
- Pegvaliase is indicated to reduce blood phenylalanine concentrations in adult patients with phenylketonuria (PKU) who have uncontrolled blood phenylalanine concentrations greater than 600 micromol/L on existing management.
- Treatment with pegvaliase should be managed by a healthcare provider experienced in the management of PKU.
- Obtain baseline blood phenylalanine concentration before initiating treatment.
- The recommended initial induction dosage for pegvaliase is 2.5 mg subcutaneously once weekly for 4 weeks. Administer the initial dose under the supervision of a healthcare provider.
- Titrate the pegvaliase dosage in a step-wise manner, based on tolerability, over at least 5 weeks, to achieve a dosage of 20 mg subcutaneously once daily according to Table 1.
- Therapeutic response may not be achieved until the patient is titrated to an effective maintenance dosage of pegvaliase. Use the lowest effective and tolerated dosage of pegvaliase.
- Assess patient tolerability, blood phenylalanine concentrations, and dietary protein and phenylalanine intake throughout treatment. Maintain the pegvaliase dosage at 20 mg subcutaneously once daily for at least 24 weeks. Consider increasing the pegvaliase dosage to a maximum of 40 mg subcutaneously once daily in patients who have been maintained continuously on 20 mg once daily for at least 24 weeks and who have not achieved either a 20% reduction in blood phenylalanine concentration from pre-treatment baseline or a blood phenylalanine concentration less than or equal to 600 micromol/L.
- Discontinue pegvaliase in patients who have not achieved a response (at least a 20% reduction in blood phenylalanine concentration from pre-treatment baseline or a blood phenylalanine concentration less than or equal to 600 micromol/L) after 16 weeks of continuous treatment with the maximum dosage of 40 mg once daily.
- During titration and maintenance of pegvaliase treatment, patients may experience blood phenylalanine concentrations below 30 micromol/L. For blood phenylalanine concentrations below 30 micromol/L, the dosage of pegvaliase may be reduced and/or dietary protein and phenylalanine intake may be modified to maintain blood phenylalanine concentrations within a clinically acceptable range and above 30 micromol/L.
- If the decision is made to readminister pegvaliase after an anaphylaxis episode, administer the first dose following the anaphylaxis episode under the supervision of a healthcare provider equipped to manage anaphylaxis and closely observe the patient for at least 60 minutes following the dose. Subsequent dose titration should be based on patient tolerability and therapeutic response.
- If a dose is missed, instruct patients to take their next dose as scheduled and to not take two doses of pegvaliase to make up for the missed dose.
- For hypersensitivity reactions, consider premedication with an H1receptor antagonist, H2receptor antagonist, and/or antipyretic prior to pegvaliase administration based upon individual patient tolerability.
- Pegvaliase is a clear to slightly opalescent, colorless to pale yellow solution available as follows:
- Injection: 2.5 mg/0.5 mL single-dose prefilled syringe
- Injection: 10 mg/0.5 mL single-dose prefilled syringe
- Injection: 20 mg/mL single-dose prefilled syringe

## Off-Label Use and Dosage (Adult)

### Guideline-Supported Use
There is limited information regarding pegvaliase Off-Label Guideline-Supported Use and Dosage (Adult) in the drug label.

### NonGuideline-Supported Use
There is limited information regarding pegvaliase Off-Label Non-Guideline-Supported Use and Dosage (Adult) in the drug label.

# Pediatric Indications and Dosage

## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding Pegvaliase FDA-Labeled Indications and Dosage (Pediatric) in the drug label.

## Off-Label Use and Dosage (Pediatric)

### Guideline-Supported Use
There is limited information regarding pegvaliase Off-Label Guideline-Supported Use and Dosage (Pediatric) in the drug label.

### NonGuideline-Supported Use
There is limited information regarding pegvaliase Off-Label Non-Guideline-Supported Use and Dosage (Pediatric) in the drug label.

# Contraindications
- None.

# Warnings
- In clinical trials of pegvaliase with induction/titration/maintenance dosing, 26 out of 285 (9%) patients experienced a total of 37 anaphylaxis episodes. The exposure-adjusted rate of anaphylaxis was highest during the induction and titration phases (0.15 episodes/personyears; 5% of patients with at least one episode) and decreased in the maintenance phase (0.04 episodes/personyears; 6% of patients with at least one episode). Signs and symptoms of anaphylaxis reported in clinical trials of pegvaliase included syncope, hypotension, hypoxia, dyspnea, wheezing, chest discomfort/chest tightness, tachycardia, angioedema (swelling of face, lips, eyes, tongue), throat tightness, skin flushing, rash, urticaria, pruritus, and gastrointestinal symptoms (vomiting, nausea, diarrhea). In clinical trials of pegvaliase, anaphylaxis generally occurred within 1 hour after injection (84%; 28/37 episodes); however, delayed episodes also occurred up to 48 hours after pegvaliase administration. Most episodes of anaphylaxis occurred within the first year of dosing (78%, 29/37 episodes), but cases also occurred after one year of dosing and up to 834 days (2.3 years) into treatment. Management of anaphylaxis in pegvaliase clinical trials included: administration of auto-injectable epinephrine (54%; 20/37 episodes), corticosteroids (54%; 20/37 episodes), antihistamines (51%; 19/37 episodes), and/or oxygen (5%; 2/37 episodes). Eighteen out of the 26 (69%) patients who experienced anaphylaxis were rechallenged with pegvaliase and 5 out of the 18 patients who were rechallenged (28%) had recurrence of anaphylaxis. All anaphylaxis episodes resolved without sequelae.
- Consider having an adult observer for patients who may need assistance in recognizing and managing anaphylaxis during pegvaliase treatment. If an adult observer is needed, the observer should be present during and for at least 60 minutes after pegvaliase administration, should be able to administer autoinjectable epinephrine, and to call for emergency medical support upon its use.
- Anaphylaxis requires immediate treatment with auto-injectable epinephrine. Prescribe autoinjectable epinephrine to all patients receiving pegvaliase and instruct patients to carry autoinjectable epinephrine with them at all times during pegvaliase treatment. Prior to the first dose, instruct the patient and observer (if applicable) on how to recognize the signs and symptoms of anaphylaxis, how to properly administer autoinjectable epinephrine, and to seek immediate medical care upon its use. Consider the risks associated with auto-injectable epinephrine use when prescribing pegvaliase. Refer to the autoinjectable epinephrine prescribing information for complete information.
- Consider the risks and benefits of readministering pegvaliase following an episode of anaphylaxis. If the decision is made to readminister pegvaliase, administer the first dose under the supervision of a healthcare provider equipped to manage anaphylaxis and closely observe the patient for at least 60 minutes following the dose. Subsequent pegvaliase dose titration should be based on patient tolerability and therapeutic response.
- Consider premedication with an H1-receptor antagonist, H2-receptor antagonist, and/or antipyretic prior to pegvaliase administration based upon individual patient tolerability.
- Pegvaliase is available only through a restricted program under a REMS
- Pegvaliase is available only through a restricted program under a REMS called the pegvaliase REMS, because of the risk of anaphylaxis.
- Notable requirements of the pegvaliase REMS include the following:
- Prescribers must be certified with the program by enrolling in the program and completing training.
- Prescribers must prescribe autoinjectable epinephrine with pegvaliase.
- Pharmacies must be certified with the program and must dispense only to patients who are authorized to receive pegvaliase.
- Patients must enroll in the program and be educated about the risk of anaphylaxis by a certified prescriber to ensure they understand the risks and benefits of treatment with pegvaliase.
- Patients must have autoinjectable epinephrine available at all times while taking pegvaliase.
- Further information, including a list of qualified pharmacies, is available at WWW.PALYNZIQREMS.COM or by telephone 1855758REMS (18557587367).
- Hypersensitivity reactions, other than anaphylaxis, have been reported in 196 out of 285 (69%) patients treated with pegvaliase. The exposure adjusted rate of other hypersensitivity reactions was highest during the induction and titration phases (4.5 episodes/person-year; 50% of patients with at least one adverse reaction) and decreased in the maintenance phase (1.5 episodes/person-year; 57% of patients with at least one adverse reaction).
- Consider premedication with an H1receptor antagonist, H2receptor antagonist, and/or antipyretic prior to pegvaliase administration based upon individual patient tolerability. Management of hypersensitivity reactions should be based on the severity of the reaction, recurrence of the reaction, and the clinical judgement of the healthcare provider, and may include dosage adjustment, temporary drug interruption, or treatment with antihistamines, antipyretics, and/or corticosteroids.

# Adverse Reactions

## Clinical Trials Experience
- Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
- The data described below reflect a total treatment exposure of 580 patient-years in 285 patients who received pegvaliase in an induction/titration/maintenance regimen in clinical trials. Of the 285 patients, 229 patients were exposed to pegvaliase for 24 weeks, 209 patients were exposed for 1 year, 137 patients were exposed for 2 years, and 85 patients were exposed for 3 years or longer. The patient population was evenly distributed between male and female patients, the mean age was 29 years (range: 16 to 56 years), and 98% of patients were White.
- The most common adverse reactions (at least 20% of patients in either treatment phase) were injection site reactions, arthralgia, hypersensitivity reactions, headache, generalized skin reactions lasting at least 14 days, pruritus, nausea, abdominal pain, oropharyngeal pain, vomiting, cough, diarrhea, and fatigue.
- Of the 285 patients exposed to pegvaliase in an induction/titration/maintenance regimen in clinical trials, 31 (11%) patients discontinued treatment due to adverse reactions. The most common adverse reactions leading to treatment discontinuation were hypersensitivity reactions (6% of patients) including anaphylaxis (3% of patients) and angioedema (1% of patients), arthralgia (4% of patients), generalized skin reactions lasting at least 14 days (2% of patients), and injection site reactions (1% of patients).
- The most common adverse reactions leading to dosage reduction were arthralgia (14% of patients), hypersensitivity reactions (9% of patients), injection site reactions (4% of patients), alopecia (3% of patients), and generalized skin reactions lasting at least 14 days (2% of patients).
- The most common adverse reactions leading to temporary drug interruption were arthralgia (13% of patients), hypersensitivity reactions (13% of patients), anaphylaxis (4% of patients), and injection site reactions (4% of patients).
- Table 2 lists adverse reactions reported in at least 15% of patients treated with pegvaliase in an induction/titration/maintenance dosage regimen in clinical trials, and illustrates the adverse reaction rates over time by treatment phase. Table 3 lists laboratory abnormalities reported in at least 10% of patients treated with pegvaliase in an induction/titration/maintenance dosage regimen in clinical trials.
- For these analyses, the induction/titration phase was defined as the time prior to reaching a stable dose (completing an 8week phase at the same dose level). Once a stable dosage was reached, patients were considered to be in the maintenance phase thereafter. Safety data for patients who reached the maintenance phase are included within either the induction/titration or maintenance phases depending on the onset date of the adverse reaction. Safety data for patients who did not reach the maintenance phase are included within the induction/titration phase. The maintenance phase includes data for patients who were previously on pegvaliase and transitioned to placebo during the randomized withdrawal period of Study 302.
- Rates of adverse reactions (adjusted for duration of exposure) generally decreased over time and for some stayed relatively stable. In the maintenance phase, the rate of adverse reactions (adjusted for duration of exposure) in patients who reached the maintenance phase was comparable across dosages evaluated. The types and rate of adverse reactions reported during the maintenance phase in patients who received 20 mg once daily and 40 mg once daily were similar.
- Rates of laboratory abnormalities (adjusted for duration of exposure) stayed relatively stable over time, except for complement C4 below lower limit of normal (LLN) and hs-CRP above 0.287 mg/dL over a 6 month period (both decreased over time) and hypophenylalaninemia (blood phenylalanine concentration below 30 micromol/L) on a single measurement (increased over time). The types and rates of laboratory abnormalities (adjusted for duration of exposure) reported during the maintenance phase in patients receiving 20 mg once daily and 40 mg once daily were similar with the exception of hsCRP above 0.287 mg/dL over a 6 month period (exposureadjusted event rates 0.04 and 0.08 in patients on 20 mg once daily and 40 mg once daily, respectively).
Arthralgia
- In clinical trials, 235 out of 285 (83%) patients experienced episodes consistent with arthralgia (includes back pain, musculoskeletal pain, pain in extremity, and neck pain). Arthralgia episodes were more frequent during the induction/titration phase (7.6 episodes/patient-year) and decreased over time (1.5 episodes/patient-year in the maintenance phase). Thirty-nine out of 285 (14%) patients had one episode of arthralgia, 32 (11%) patients had 2 episodes of arthralgia, 18 (6%) had 3 episodes of arthralgia, and 146 (51%) had 4 or more episodes of arthralgia. Arthralgia occurred as early as after the first dose of pegvaliase and occurred at any time during treatment. The mean duration of arthralgia was 14 days (median: 3 days, range: 1 to 580 days), and 19% of arthralgia episodes had a duration of at least 14 days. Severe arthralgia (severe pain limiting self-care activities of daily living) was reported by 14 (5%) patients. In addition to arthralgia, other joint-related signs and symptoms reported were: joint swelling (22 patients; 8%), joint stiffness (22 patients; 8%), and musculoskeletal stiffness (19 patients; 7%). Arthralgia episodes were managed with medications (e.g., nonsteroidal anti-inflammatory drugs, glucocorticoids, and acetaminophen), pegvaliase dosage reduction (4% of episodes), pegvaliase interruption (4% of episodes), or pegvaliase withdrawal (0.6% of episodes). 97% of arthralgia episodes were reported as resolved at the time of last observation (up to 59 months of followup).
Injection Site Reactions
- Injection site reactions were reported as early as after the first dose of pegvaliase and occurred at any time during treatment. Injection site reactions were more frequent during the induction/titration phase (21.9 episodes/patient-years) and decreased over time (4 episodes/patientyears in the maintenance phase). The mean duration of injection site reaction was 8 days (median: 2 days, range: 1 to 970 days), and 7% of injection site reactions had a duration of at least 14 days. 99% of injection site reactions were reported as resolved at the time of last observation (up to 59 months of followup).
- Three injection site reactions consistent with granulomatous skin lesions were reported (each reaction occurring in one patient): granulomatous dermatitis (occurred after 464 days of pegvaliase treatment and lasted 16 days), xanthogranuloma (occurred after 378 days of pegvaliase treatment and lasted 638 days) was treated with a topical antihistamine, corticosteroid, and pegvaliase treatment was discontinued, and necrobiosis lipoidica diabeticorum (occurred after 281 days of pegvaliase treatment and lasted 281 days). Necrobiosis lipoidica diabeticorum was treated with steroid injections and complicated by Pseudomonas infection. All three injection site reactions resolved.
- One patient reported soft tissue infection (occurred after 196 days of pegvaliase treatment and lasted 8 days) associated with mesenteric panniculitis treated with antibiotics, which resulted in treatment discontinuation.
Generalized Skin Reactions (not limited to the injection site) Lasting at Least 14 Days
- In clinical trials, 125 out of 285 (44%) patients treated with pegvaliase experienced generalized skin reactions (not limited to the injection site) lasting at least 14 days. Mean duration of these reactions was 58 days (median: 34 days; range: 14 to 638 days). Generalized skin reactions were more frequent during the induction/titration phase (0.7 episodes/patientyears), and decreased over time (0.3 episodes/patient-years in the maintenance phase).
- The mean time from first dose of pegvaliase to onset of skin reactions was 319 days (median: 169 days; range: 2 to 1237 days). 5% of these reactions persisted at least 180 days, and 85% of these reactions were reported as resolved at the time of last observation (up to 59 months of followup).
Angioedema
- In clinical trials, 22 out of 285 (8%) patients experienced 45 episodes of angioedema (symptoms included: pharyngeal edema, swollen tongue, lip swelling, mouth swelling, eyelid edema and face edema) occurring independent of anaphylaxis. Angioedema (included under Hypersensitivity in Table 2) was more frequent during the induction/titration phase (0.15 episodes/patient-year) and decreased over time (0.06 episodes/patient-year in the maintenance phase). Three patients discontinued treatment. All episodes resolved. Angioedema can present as a symptom of anaphylaxis.
Serum Sickness
- In clinical trials, serum sickness was reported in 7 out of 285 (2%) patients. Serum sickness episodes were more frequent during the induction/titration phase (0.04 episodes/patient-year) and decreased over time (less than 0.01 episodes/patient-year during the maintenance phase). All serum sickness reactions resolved without sequelae (duration of serum sickness ranged from 1 to 8 days). Out of the 7 patients who experienced serum sickness, 5 patients continued treatment without a recurrence, and managed serum sickness with drug interruption, dosage reduction and/or concomitant medication. Two patients discontinued treatment.
- As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to pegvaliase in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.
- All patients treated with pegvaliase developed a sustained total anti-drug antibody (TAb) response with a majority of patients (91%; N = 235/258) developing that response by Week 4 of treatment. Mean TAb titers peaked 2 weeks after pegvaliase initiation and remained elevated throughout treatment (greater than 1 year after treatment initiation). Anti-phenylalanine ammonia lyase (PAL) IgM antibodies were detected in all patients with a majority of patients (98%; N = 265/270) becoming positive for anti-PAL IgM by 2 months after treatment initiation. AntiPAL IgG antibodies were detected in almost all patients (N = 226/227) by 4 months after treatment initiation. Mean anti-PAL IgM and IgG titers peaked at approximately 3 and 6 months, respectively, after treatment initiation and remained elevated throughout treatment (greater than 1 year after treatment initiation). Drug-induced anti-PEG IgM and IgG antibodies were detected in the majority of patients (98%; N = 277/284 for IgM; and 278/284 for IgG) with mean titers for both peaking at 1 to 3 months after treatment initiation. Neutralizing antibodies (NAb) capable of inhibiting PAL enzyme activity were detected on at least one measurement in the majority of patients (88%; N = 249/284) over time. Mean NAb titers peaked and reached a plateau at 16 to 20 weeks of treatment and then remained present throughout treatment (greater than 1 year after treatment initiation).
- Twenty-five of 26 patients who had anaphylaxis were tested for antipegvaliasepqpz IgE antibodies, which recognize the PEGylated protein product. Of the 25 patients tested for antipegvaliasepqpz IgE antibodies, 24 patients tested negative. The one patient who tested positive for antipegvaliasepqpz IgE antibodies on the screening test did not have sufficient sample to confirm IgE positivity. This patient tested negative for antipegvaliasepqpz IgE at routine visits prior to and after the anaphylaxis episode (not at times of anaphylaxis). Sixtyeight of 285 patients in clinical trials were tested for both antiPAL IgE antibodies, which recognize the recombinant PAL protein, and for antipegvaliasepqpz IgE antibodies during routine study visits (not at times of anaphylaxis episodes) or during additional visits for hypersensitivity reactions. Of those 68 patients, 5 (7%) tested positive at least once for antiPAL IgE antibodies but negative for antipegvaliasepqpz IgE antibodies.
- The highest frequency of hypersensitivity reactions (consistent with a Type III immune complex-mediated hypersensitivity mechanism) occurred within the first 6 months of pegvaliase treatment when the mean circulating immune complex (CIC) concentrations were at their highest and mean complement C3 and C4 concentrations were at their lowest. Mean CIC concentrations decreased and complement levels increased over time as the exposure-adjusted rate of hypersensitivity reactions decreased. IgG and IgM CIC concentrations were above the upper limit of normal in 63% (N = 164/259) and 41% of patients (N = 106/259), respectively, at 12 weeks of pegvaliase treatment. The incidence of CIC positivity decreased over time. 61% of patients (N = 110/180) had complement C3 concentrations less than lower limit of normal (LLN) at 6 months after treatment initiation and 38% of patients (N = 94/248) had complement C4 concentrations less than LLN at 3 months after treatment initiation. The incidence of low complement C3 and C4 concentrations decreased over time, but approximately 39% (N = 19/49) and 12% (N = 6/49) of patients had low C3 and C4 concentrations, respectively, at 36 months after treatment initiation.
- Higher antibody responses for all antibody analytes, including NAb, were associated with lower mean trough pegvaliasepqpz concentrations and with higher blood phenylalanine concentrations. Hypersensitivity reactions occurred more frequently in patients with higher antibody titers for some but not all antibody analytes. Patients with higher mean change in IgG CIC concentrations from pre-treatment baseline tended to have higher discontinuation rates than patients with lower mean change in IgG CIC concentrations. Mean antibody titers for antiPAL IgG and IgM, TAb, and NAb remained relatively stable with long-term treatment.

## Postmarketing Experience
There is limited information regarding Pegvaliase Postmarketing Experience in the drug label.

# Drug Interactions
- Effect of Pegvaliase on Other PEGylated Products
- In a single dose study of pegvaliase in adult patients with PKU, two patients receiving concomitant injections of medroxyprogesterone acetate suspension (a formulation containing PEG 3350) experienced hypersensitivity reactions. One of the two patients experienced a hypersensitivity reaction on day 15 after a single pegvaliase dosage of 0.67 mg within 15 minutes following medroxyprogesterone acetate injectable suspension, and subsequently experienced anaphylaxis on day 89 within 30 minutes after the next dose of medroxyprogesterone acetate injectable suspension. The other patient experienced a hypersensitivity reaction on day 40 after a single pegvaliase dosage of 0.08 mg within 10 minutes following medroxyprogesterone acetate injectable suspension. Both patients had high antiPEG IgG antibody titers at or around the time of the hypersensitivity reactions.
- In pegvaliase clinical trials, the majority of patients developed antiPEG IgM and IgG antibodies after treatment with pegvaliase. The clinical effects of concomitant treatment with different PEGylated products is unknown. Monitor patients treated with pegvaliase and concomitantly with other PEGylated products for hypersensitivity reactions including anaphylaxis.

# Use in Specific Populations

### Pregnancy
Pregnancy Category (FDA):
- Based on findings in studies of pregnant animals without PKU treated with pegvaliase-pqpz, pegvaliase may cause fetal harm when administered to a pregnant woman. Limited available data with pegvaliase-pqpz use in pregnant women are insufficient to inform a drug-associated risk of adverse developmental outcomes. There are risks to the fetus associated with poorly controlled phenylalanine concentrations in women with PKU during pregnancy including increased risk for miscarriage, major birth defects (including microcephaly, major cardiac malformations), intrauterine fetal growth retardation, and future intellectual disability with low IQ; therefore, phenylalanine concentrations should be closely monitored in women with PKU during pregnancy. Advise pregnant women of the potential risks to the fetus.
- A reproduction study in pregnant rabbits treated with pegvaliasepqpz demonstrated a high incidence of fetal malformations throughout the skeletal system, and in kidneys, lungs, and eyes. Embryo-fetal toxicity (increased resorptions and reduced fetal weight) was also observed. These effects occurred at 7.5 times the maximum recommended daily dose and were associated with strong signs of maternal toxicity, including marked reductions in weight gain and food consumption, and death. A reproduction study in pregnant rats treated with pegvaliase-pqpz demonstrated an increase in skeletal variations, with no malformations observed. The effects in rats occurred at 4.2 times the maximum recommended daily dose. In a pre-/post-natal development study in rats, pegvaliasepqpz produced reduced survival of offspring during lactation, decreases in pup weight and litter size, and delayed sexual maturation of offspring when administered daily at 19.4 times the maximum recommended daily dose. The effects on rat embryofetal and post-natal development were associated with maternal toxicity.
- All pregnancies have a background risk of major birth defects, pregnancy loss, or other adverse pregnancy outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. The estimated background risk of major birth defects and miscarriage in pregnant women with PKU who maintain blood phenylalanine concentrations greater than 600 micromol/L during pregnancy is greater than the corresponding background risk for pregnant women without PKU.
- There is a pregnancy surveillance program for pegvaliase. If pegvaliase is administered during pregnancy, or if a patient becomes pregnant while receiving pegvaliase or within one month following the last dose of pegvaliase, healthcare providers should report pegvaliase exposure by calling 1-866-906-6100.
Disease-Associated Maternal and/or Embryo-Fetal Risk
- Uncontrolled blood phenylalanine concentrations before and during pregnancy are associated with an increased risk of adverse pregnancy outcomes and fetal adverse effects. To reduce the risk of hyperphenylalaninemia-induced fetal adverse effects, blood phenylalanine concentrations should be maintained between 120 and 360 micromol/L during pregnancy and during the 3 months before conception.
Dose Adjustments During Pregnancy and the Postpartum Period
- Phenylalanine concentrations below 30 micromol/L in pregnant women with PKU treated with pegvaliase may be associated with adverse fetal outcomes. Monitor blood phenylalanine concentrations during pregnancy and adjust the dosage of pegvaliase or modify dietary protein and phenylalanine intake to avoid blood phenylalanine concentrations below 30 micromol/L.
Human Data
- Uncontrolled Maternal PKU: Available data from the Maternal Phenylketonuria Collaborative Study on 468 pregnancies and 331 live births in pregnant women with PKU demonstrated that uncontrolled phenylalanine concentrations above 600 micromol/L are associated with an increased risk for miscarriage, major birth defects (including microcephaly, major cardiac malformations), intrauterine fetal growth retardation, and future intellectual disability with low IQ.
- Limited data from case reports of pegvaliase use in pregnant women are insufficient to determine a drugassociated risk of adverse developmental outcomes.
Animal Data
- All developmental toxicity studies were conducted in animals (rats and rabbits) without PKU, in which treatment with pegvaliase-pqpz produced a dose-dependent reduction in maternal blood phenylalanine concentrations. At doses that produced maternal toxicity and/or effects on embryo-fetal development, the maternal plasma phenylalanine concentrations were markedly reduced compared to the control group. The contribution of maternal phenylalanine depletion to the incidence of embryofetal developmental effects was not evaluated.
&Subcutaneous administration of 5 mg/kg/day pegvaliase-pqpz (7.5 times the maximum recommended daily dose based on bodyweight ) in pregnant rabbits during the period of organogenesis produced embryo-lethality (increased resorptions), marked reduction in fetal weight, and fetal malformations. The malformations included multiple external abnormalities of the head, body and limbs, multiple soft tissue malformations (reduced size or absence of kidneys, diaphragmatic hernia, corneal opacity, discoloration or reduced size of eyes, and reduced size of lungs) and multiple skeletal malformations of the craniofacial bones, vertebrae, sternebrae, ribs, pelvis, limbs, and digits. An increase in variations and delayed ossification was also observed in all skeletal regions. The adverse developmental effects were associated with maternal toxicity, as indicated by marked impairment of weight gain and food consumption. Deaths associated with weight loss and abortion occurred in 8% of the pregnant rabbits treated with 5 mg/kg/day pegvaliase-pqpz.
- Subcutaneous administration of 2 mg/kg/day pegvaliasepqpz (3 times the maximum recommended daily dose based on bodyweight ) in pregnant rabbits had no adverse effects on embryo-fetal development. Systemic exposure to pegvaliasepqpz was detected in fetuses from rabbits treated with 2 or 5 mg/kg/day.
- Pegvaliase-pqpz increased fetal alterations when administered daily in pregnant rats at doses of 8 mg/kg subcutaneously and higher (4.2 times the human steady-state area under the curve  at the maximum recommended daily dose) during a 28day premating period, mating, and through the period of organogenesis. The fetal alterations were limited to skeletal variations such as cervical ribs, bifid centra of lumbar and thoracic vertebrae, and incomplete ossification of squamosal bones, frontal bones, lumbar vertebra arch, and ribs. Daily administration of 20 mg/kg subcutaneously (19.4 times the human steady-state AUC at the recommended maximum daily dose) to pregnant rats produced reductions in litter sizes and fetal weights, which was associated with maternal toxicity (decreased body weight, ovarian weight, and food consumption). The decrease in litter sizes at 20 mg/kg subcutaneously was secondary to reductions in corpora lutea and implantations. Systemic exposure to pegvaliase-pqpz was detected in fetuses from rats treated with 20 mg/kg of pegvaliase-pqpz (19.4 times the human steady-state AUC at the recommended maximum daily dose). Subcutaneous administration of 2 mg/kg/day pegvaliase-pqpz (less than the human steady state AUC at the maximum recommended daily dose) in pregnant rats had no adverse effects on embryofetal development.
- Pegvaliase-pqpz decreased pup weight, litter size, and survival of offspring during lactation, and delayed sexual maturation of offspring when administered daily in rats at 20 mg/kg subcutaneously (19.4 times the human steadystate AUC at the recommended maximum daily dose), with dosing starting before mating and continuing through lactation. The effects in offspring were associated with maternal toxicity. No effects in offspring were observed at 8 mg/kg/day subcutaneously (4.2 times the human steady-state AUC at the recommended maximum daily dose). This study lacked a complete evaluation of physical and neurobehavioral development in offspring; however, no effects of pegvaliasepqpz were noted in tests of learning and memory.
Pregnancy Category (AUS): 
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Pegvaliase in women who are pregnant.

### Labor and Delivery
There is no FDA guidance on use of Pegvaliase during labor and delivery.

### Nursing Mothers
- There are no data on the presence of pegvaliase-pqpz in human milk, the effects on the breastfed infant, or the effects on milk production. A pre-/post-natal study in rats showed that pegvaliase-pqpz is present in rat milk and that administration of pegvaliase-pqpz during lactation decreased pup weight and survival. However, systemic absorption of pegvaliase-pqpz was not detected in the rat pups. Pegvaliase may cause low phenylalanine concentrations in human milk. The developmental and health benefits of breastfeeding should be considered along with the clinical need for pegvaliase treatment and any potential adverse effect on the breastfed infant from pegvaliase or from the underlying condition.
- Monitor blood phenylalanine concentrations in breastfeeding women treated with pegvaliase.

### Pediatric Use
- The safety and effectiveness of pegvaliase in pediatric patients have not been established.

### Geriatic Use
- Clinical studies of pegvaliase did not include patients aged 65 years and older.

### Gender
There is no FDA guidance on the use of Pegvaliase with respect to specific gender populations.

### Race
There is no FDA guidance on the use of Pegvaliase with respect to specific racial populations.

### Renal Impairment
There is no FDA guidance on the use of Pegvaliase in patients with renal impairment.

### Hepatic Impairment
There is no FDA guidance on the use of Pegvaliase in patients with hepatic impairment.

### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Pegvaliase in women of reproductive potentials and males.

### Immunocompromised Patients
There is no FDA guidance one the use of Pegvaliase in patients who are immunocompromised.

# Administration and Monitoring

### Administration
- Each prefilled syringe of pegvaliase is intended for use as a single subcutaneous injection.
- Inspect pegvaliase visually for particulate matter and discoloration prior to administration. Pegvaliase is a clear to slightly opalescent, colorless to pale yellow solution. *Discard if discolored, cloudy, or if particulate matter is present.
- Prior to first dose of pegvaliase, prescribe auto-injectable epinephrine, and instruct the patient and observer (if applicable) on how to recognize the signs and symptoms of anaphylaxis, how to properly administer auto-injectable epinephrine, and to seek immediate medical care upon its use.
- Perform initial administration(s) and/or readministration after an anaphylaxis episode under the supervision of a healthcare provider equipped to manage anaphylaxis, and closely observe patients for at least 60 minutes following injection. Prior to self-injection, confirm patient competency with selfadministration.
- Consider having an adult observer for patients who may need assistance in recognizing and managing anaphylaxis during pegvaliase treatment. If an adult observer is needed, the observer should be present during and for at least 60 minutes after each pegvaliase administration, should be able to administer auto-injectable epinephrine, and to call for emergency medical support upon its use.
- The recommended injection sites for pegvaliase are: the front middle of thighs and the abdomen at least 2 inches (five centimeters) away from the navel. If a caregiver is giving the injection, the top of buttocks and the back of the upper arms are also appropriate injection sites.
- Do not inject pegvaliase into moles, scars, birthmarks, bruises, rashes, or areas where the skin is hard, tender, red, damaged, burned, inflamed, or tattooed. Check the injection site for redness, swelling, or tenderness.
- Rotate sites for subcutaneous injections of pegvaliase. If more than one injection is needed for a single dose of pegvaliase, the injection sites should be at least 2 inches away from each other. The second injection site can be on the same part of the body or a different part of the body.

### Monitoring
- Reduction in blood phenylalanine concentrations is indicative of efficacy.
- Improvement in inattention and mood may indicate efficacy.
- Blood phenylalanine concentration: Prior to initiation, every 4 weeks until a maintenance dose is reached, and then periodically throughout treatment.
- Signs and symptoms of anaphylaxis: Monitor for at least 60 minutes after initial dose or upon reinitiation of therapy after a previous episode of anaphylaxis.
- Dietary protein and phenylalanine intake: Throughout therapy.
- After initiating treatment with pegvaliase, obtain blood phenylalanine concentrations every 4 weeks until a maintenance dosage is established. After a maintenance dosage is established, periodic blood phenylalanine monitoring is recommended to assess blood phenylalanine control.
- Monitor patients dietary protein and phenylalanine intake throughout treatment with pegvaliase and counsel them on how to adjust their dietary intake, as needed, based on blood phenylalanine concentrations.

# IV Compatibility
There is limited information regarding the compatibility of Pegvaliase and IV administrations.

# Overdosage
There is limited information regarding Pegvaliase overdosage.  If you suspect drug poisoning or overdose, please contact the National Poison Help hotline (1-800-222-1222) immediately.

# Pharmacology

## Mechanism of Action
- Pegvaliase-pqpz is a PEGylated phenylalanine ammonia lyase (PAL) enzyme that converts phenylalanine to ammonia and transcinnamic acid. It substitutes for the deficient phenylalanine hydroxylase (PAH) enzyme activity in patients with PKU and reduces blood phenylalanine concentrations.

## Structure
(Description with picture)

## Pharmacodynamics
- Pegvaliase treatment of adult patients with PKU resulted in the reduction of blood phenylalanine concentrations from pre-treatment baseline. The reduction of blood phenylalanine concentrations diminished with decreased pegvaliasepqpz plasma concentrations.

## Pharmacokinetics
- The pharmacokinetics of pegvaliasepqpz exhibit high inter-patient and intra-patient variability due to the heterogeneity of the immune response in adult patients with PKU. Higher antibody titers correlated with higher apparent clearance of pegvaliasepqpz. In the first eight weeks of induction and titration treatment, plasma pegvaliasepqpz concentrations were low to not measurable. At steady state during maintenance treatment with pegvaliase 20 mg and 40 mg subcutaneously once daily, the mean  SD (range) plasma trough pegvaliasepqpz concentrations were: 11.2  9.0 (0.21 to 29.6) mg/L and 10.4  12.7 (0.18 to 43.1) mg/L, respectively. The following pharmacokinetic parameters were observed in adult patients with PKU treated with pegvaliase at maintenance dosages of 20 mg once daily and 40 mg once daily.
- The median Tmax was approximately 8 hours. The mean  SD (range) peak concentration (Cmax) at steady state was: 14.0  16.3 (0.26 to 68.5) mg/L and 16.7  19.5 (0.24 to 63.8) mg/L, respectively.
- The mean  SD (range) apparent volume of distribution was 26.4  64.8 (1.8 to 241) L and 22.2  19.7 (3.1 to 49.5) L, respectively.
- The mean  SD (range) apparent clearance at steady state was 0.39  0.87 (0.018 to 3.66) L/h and 1.25  2.46 L/h (0.034 to 8.88), respectively. The mean  SD (range) half-life was 47  42 (14 to 132) hours and 60  45 (14 to 127) hours, respectively.
- The metabolism of phenylalanine ammonia lyase is expected to occur via catabolic pathways and be degraded into small peptides and amino acids.
- The route of elimination of pegvaliasepqpz has not been studied in humans.

## Nonclinical Toxicology
- Carcinogenicity and genotoxicity studies have not been performed with pegvaliasepqpz. Based on its mechanism of action, pegvaliasepqpz is not expected to be tumorigenic.
- Pegvaliase-pqpz produced impaired fertility in female rats at 20 mg/kg/day subcutaneously (19.4 times the human steadystate AUC at the maximum recommended daily dose), as indicated by decreases in corpora lutea, implantations, and litter size. These effects were associated with toxicity (decreased body weight, ovarian weight, and food consumption). No effects on mating or fertility were observed in female rats with 8 mg/kg/day subcutaneously (4.2 times the human steadystate AUC at the maximum recommended daily dose) or in male rats with 20 mg/kg/day subcutaneously.
- In rats without PKU treated with pegvaliase-pqpz, dose-dependent vacuolation in multiple organs and tissues was observed in the 4 and 26week repeat dose toxicity studies at doses of 8 mg/kg subcutaneously or greater administered twice weekly (less than the human steady state AUC at the maximum recommended daily dose). Vacuolation occurred in renal tubule cells and in histiocytic cells of the liver, spleen, testes, adrenal cortex, mesenteric lymph node, and mandibular lymph node. Vacuolation in histiocytes of the affected organs and tissues persisted after cessation of treatment. The vacuolation observed in these studies was not associated with organrelated toxicities as determined by clinical chemistry/urinalysis and histopathological examination. The clinical significance of these findings and functional consequences are unknown.
- In the 39week repeat dose toxicity study in monkeys, pegvaliase-pqpz 3 mg/kg subcutaneously twice weekly (3 times the human steady state AUC at the maximum recommended daily dose) produced systemic arteritis involving small arteries and arterioles in a wide range of organs and tissues (kidney, urinary bladder, pancreas, gallbladder, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, lung, heart, sciatic nerve, lacrimal gland, mandibular lymph node, epididymis, seminal vesicle, ovary, uterus, cervix, and vagina) and in subcutaneous injection sites. Arteritis was likely due to the immune-mediated response (e.g., immune complex deposition in blood vessels) associated with chronic administration of a foreign protein to the animals. The incidence and severity of systemic arteritis was dose-dependent. The vascular inflammation observed in this study was not associated with organ related toxicities as determined by clinical pathology parameters (hematology, clinical chemistry, and urinalysis) and histopathological examination.
- Studies of longer duration in rats and monkeys treated with pegvaliasepqpz have not been conducted.

# Clinical Studies
- Study 165301 (referred to as Study 301, NCT01819727) was an open-label randomized, multi-center study of adults with PKU to assess safety and tolerability of self-administered pegvaliase in an induction/titration/maintenance regimen with a target maintenance dose of 20 mg subcutaneously once daily or 40 mg subcutaneously once daily. At pegvaliase treatment initiation, 253 patients demonstrated inadequate blood phenylalanine control (blood phenylalanine concentration greater than 600 micromol/L) on existing management, and 8 patients had blood phenylalanine concentrations less than or equal to 600 micromol/L. Existing management options included prior or current restriction of dietary phenylalanine and protein intake, and/or prior treatment with sapropterin dihydrochloride. Patients previously treated with sapropterin dihydrochloride were required to discontinue use at least 14 days prior to the first dose.
- The 261 enrolled patients were aged 16 to 55 years (mean: 29 years) and had a baseline mean (range) blood phenylalanine of 1,233 (285, 2330) micromol/L. One hundred forty nine out of 261 (57%) patients were taking medical food at baseline and 41 out of 261 patients (16%) were on a protein-restricted diet at baseline (defined as receiving greater than 75% of total protein intake from medical food). Patients were randomized (1:1) to one of two target maintenance dosage arms: 20 mg once daily or 40 mg once daily. Patients were titrated to reach their randomized target dosage of 20 mg once daily or 40 mg once daily. The duration of titration varied among patients and was based on patient tolerability. Of the 261 enrolled patients, 195 (75%) patients reached their randomized maintenance dosage (103 in the 20 mg once daily arm, 92 in the 40 mg once daily arm). Among the patients who reached their randomized maintenance dosage, patients in the 20 mg once daily randomized arm reached their maintenance dosage at a median time of 10 weeks (range: 9 to 29 weeks) and patients in the 40 mg once daily arm reached their maintenance dosage at a median time of 11 weeks (range: 10 to 33 weeks).
- Of the 261 patients who enrolled in Study 301, 54 (21%) patients discontinued treatment during Study 301, 4 patients completed Study 301 and did not continue to Study 165302 (referred to as Study 302, NCT01889862), 152 patients continued to the eligibility period of Study 302, and 51 patients continued directly from Study 301 into the longterm treatment period of Study 302.
- A total of 164 adult patients with PKU who were previously-treated with pegvaliase (152 patients from Study 301 and 12 patients from other pegvaliase trials) enrolled in Study 302 and continued treatment with pegvaliase in Study 302 for up to 13 weeks to assess eligibility for randomized withdrawal period.
Randomized Withdrawal Period
- Following this period of up to 13 weeks of additional pegvaliase treatment in Study 302, eligibility for entry into the efficacy assessment period (randomized withdrawal period) was determined by whether a patient achieved at least a 20% reduction in blood phenylalanine concentration from pre-treatment baseline (when in previous studies). Eightysix out of 164 patients (52%) met this response target and continued into the randomized withdrawal period. In the double-blind, placebo-controlled, randomized withdrawal period, patients were randomized in a 2:1 ratio to either continue their maintenance pegvaliase dosage or to receive matching placebo for a total of 8 weeks. The treatment difference in least squares (LS) mean change in blood phenylalanine concentration from the Study 302 randomized withdrawal baseline to randomized withdrawal Week 8 for each randomized study arm is shown in Table 5. Mean blood phenylalanine concentrations at pre-treatment baseline (Study 301 or other pegvaliase trials) are also shown in Table 5. At Study 302 randomized withdrawal Week 8, pegvaliasetreated patients (20 mg once daily or 40 mg once daily) maintained their blood phenylalanine concentrations as compared to their randomized withdrawal baseline, whereas patients randomized to matching placebo (20 mg once daily or 40 mg once daily) returned to their pretreatment baseline blood phenylalanine concentrations (Figure 1).
- Of 118 patients from Study 301 with a pretreatment baseline blood phenylalanine concentration greater than 600 micromol/L who were randomized to and received at least one dose of 20 mg once daily pegvaliase, 108 patients, 98 patients, and 51 patients were treated for at least 24 weeks, 48 weeks, and 96 weeks, respectively.
- Of the 118 patients, 53 patients reached their first response (at least a 20% reduction in blood phenylalanine concentration from pre-treatment baseline or a blood phenylalanine concentration less than or equal to 600 micromol/L) by 4 weeks of treatment with 20 mg once daily and 28 patients reached their first response between Weeks 4 and 24 with 20 mg once daily. Of the 118 patients, 25 patients escalated their dosage from 20 mg once daily to 40 mg once daily before reaching a first response; of those 25 patients, 8 patients reached their first response by 4 weeks of treatment with 40 mg once daily and 6 patients reached their first response between Weeks 4 and 16 with 40 mg once daily.

# How Supplied
- Pegvaliase (pegvaliase-pqpz) injection is supplied as a preservative-free, sterile, clear to slightly opalescent, colorless to pale yellow solution. All dosage strengths of pegvaliase are provided in a 1 mL glass syringe with a 26 gauge, 0.5 inch needle.
- Each carton contains 1 or 10 trays with single-dose prefilled syringe(s), Prescribing Information, Medication Guide, and Instructions for Use. The following packaging configurations are available.

## Storage
- Store in refrigerator at 36F to 46F (2C to 8C) in its original carton to protect from light.
- Do not freeze or shake.
- For patients: If needed, store pegvaliase in the original carton at room temperature between 68F to 77F (20C to 25C) for up to 30 days. Record the date removed from refrigeration on the carton. Once stored at room temperature, do not return the product to the refrigerator.
- The shelf-life expires after storage at room temperature for 30 days, or after the expiration date on the product carton, whichever is earlier.

# Images

## Drug Images

## Package and Label Display Panel

# Patient Counseling Information
- Advise the patient to read the FDA-approved patient labeling.
- Advise patients that pegvaliase may cause hypersensitivity reactions, including anaphylaxis that can occur at any time. Instruct patients to recognize the signs and symptoms of anaphylaxis.
- Instruct patients to carry auto-injectable epinephrine with them at all times during pegvaliase treatment. Instruct the patient and observer (if applicable) on the appropriate use of autoinjectable epinephrine for anaphylaxis.
- Instruct patients who experience anaphylaxis to seek immediate medical care, discontinue therapy, and resume treatment only at the instruction of a healthcare provider.
- Pegvaliase is available only through a restricted program called the pegvaliase REMS. Inform the patient of the following notable requirements:
- Patients must be enrolled in the pegvaliase REMS.
- Patients must be educated about the risk of anaphylaxis by a certified prescriber to ensure they understand the risks and benefits of treatment with pegvaliase.
- Patients must fill a prescription for auto-injectable epinephrine and carry it with them at all times.
- Patients will be given a pegvaliase Patient Wallet Card that they should carry with them at all times. This card describes symptoms which, if experienced, should prompt the :*patient and observer (if applicable) to immediately seek medical care. Advise the patient to show the pegvaliase Wallet Card to other treating healthcare providers.
- pegvaliase is available only from certified pharmacies participating in the program. Therefore, provide patients with the telephone number and website for information on how to obtain the product.
- Advise patients to monitor their dietary protein and phenylalanine intake throughout treatment with pegvaliase, and adjust intake as directed by their healthcare provider based on blood phenylalanine concentrations.
- Provide appropriate instruction for methods of self-injection, including careful review of the pegvaliase Medication Guide and Instructions for Use. Instruct patients in the use of aseptic technique when administering pegvaliase.
- Inform patients that a healthcare provider will show them or their caregiver how to prepare to inject pegvaliase before self-administering.
- Advise patients not to inject into moles, scars, birthmarks, bruises, rashes, or areas where the skin is hard, tender, red, damaged, burned, inflamed, or tattooed.
- Advise patients to rotate areas of injection with each dose. Advise patients to check the injection site for redness, swelling, and tenderness, and to contact their healthcare provider if they have a skin reaction and it does not clear up, or worsens.
- Advise patients to follow sharps disposal recommendations patients on safe disposal procedures.
- Advise patients that the shelflife expires after storage at room temperature for 30 days or after the expiration date on the product carton, whichever is earlier.
- Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females to inform their healthcare provider of a known or suspected pregnancy.
- Advise women who are exposed to pegvaliase during pregnancy or who become pregnant within one month following the last dose of pegvaliase that there is a pregnancy surveillance program that monitors pregnancy outcomes. Encourage these patients to report their pregnancy to BioMarin (18669066100).

# Precautions with Alcohol
Alcohol-Pegvaliase interaction has not been established. Talk to your doctor regarding the effects of taking alcohol with this medication.

# Brand Names
- Palynziq

# Look-Alike Drug Names
There is limited information regarding Pegvaliase Look-Alike Drug Names in the drug label.

# Drug Shortage Status
Drug Shortage

# Price