SUMMARY STATEMENT

PROGRAM CONTACT: ( Privileged Communication ) Release Date: 11/30/2016

Revised Date:

Application Number: 1 R41 AI131792-01

Principal Investigator 

SMITH, JAMES

Applicant Organization: SANO CHEMICALS, INC

Review Group: ZRG1 BCMB-G (10)

Center for Scientific Review Special Emphasis Panel 

SBIR/STTR Applications in Drug Discovery and Development

Meeting Date: 11/07/2016 RFA/PA: PA16-303

Council: JAN 2017 PCC: M30D

Requested Start: 04/01/2017

Project Title: Lead Compound Discovery from Engineered Analogs of Occidiofungin

SRG Action: Impact Score:

Next Steps: Visithttp://grants.nih.gov/grants/next_steps.htm

Human Subjects: 10-No human subjects involved

Animal Subjects: 10-No live vertebrate animals involved for competing appl.

Project

Year

Direct Costs

Requested

Estimated

Total Cost

1 

TOTAL

ADMINISTRATIVE BUDGET NOTE: The budget shown is the requested budget and has not been adjusted 

to reflect any recommendations made by reviewers. If an award is planned, the costs will be calculated by 

Institute grants management staff based on the recommendations outlined below in the COMMITTEE 

BUDGET RECOMMENDATIONS section.

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1 R41 AI131792-01 2 ZRG1 BCMB-G (10)
 

SMITH, J 

1R41AI131792-01 SMITH, JAMES 

RESUME AND SUMMARY OF DISCUSSION: Funds are requested to develop a new class of broad 

spectrum antifungal agents based on a cyclic nonribosomally synthesized peptide, occidiofungin, for 

the treatment of systemic fungal infections. An entirely novel mechanism of action of occidiofungin 

speaks to a high level of conceptual innovation and makes the proposed work very promising. The 

proposed experimental strategy is based on abundant and highly encouraging preliminary results; the 

work is well planned and full feasibility will likely be established at the end of Phase I. The investigators 

are highly qualified to perform these studies and the environment is adequate for the stated goals. 

Overall, very high enthusiasm was expressed for this scientifically solid and potentially impactful 

antifungal drug discovery proposal. 

DESCRIPTION (provided by applicant): Occidiofungin is a cyclic nonribosomally synthesized 

antifungal peptide with submicromolar fungicidal activity against a broad spectrum of fungi. 

Occidiofungin is produced by the Gram-negative bacterium Burkholderia contaminans. From our 

structural characterization studies, occidiofungin was determined to have a unique chemical 

composition. Our studies have also revealed that occidiofungin has a novel mechanism of action. 

Occidiofungin is a potent antifungal against fluconazole and caspofungin-resistant Candida albicans. 

Occidiofungin triggers cell death by inducing apoptosis in yeast cells. Occidiofungin has minimal toxicity 

in mice dosed with 2 mg/kg in a 28 day toxicity study. Furthermore, occidiofungin was shown to reduce 

Candida glabrata load in the kidneys of infected mice. All these studies point to the need to further the 

preclinical development of this novel compound. A major need for furthering investigational studies on 

this unique antifungal compound is the identification of a lead molecule for preclinical testing. The goal 

of this application is to screen a library of natural and semi-synthetic analogs of occidiofungin for 

bioactivity testing. The compound that has the best properties will be used in the required preclinical 

tests that are compulsory before our initial meeting with the FDA. This work is necessary for furthering 

additional studies aimed at developing the antifungal compound as a new therapeutic. 

PUBLIC HEALTH RELEVANCE: The proposal addresses the need for the development of a novel 

broad spectrum antifungal for the treatment of systemic fungal infections. We will isolate natural 

analogs and produce semi-synthetic analogs of the antifungal occidiofungin. This works is essential for 

identifying a lead compound for preclinical studies that are needed for filing an Investigational New 

Drug (IND) application. 

CRITIQUE 1: 

Significance: 2 

Investigator(s): 1 

Innovation: 2 

Approach: 4 

Environment: 1 

Overall Impact: The applicant proposes to continue efforts to characterize the antifungal properties of 

the cyclic peptide occidiofungins. Aim 1, which involves a combination of biosynthetic and synthetic 

approaches to prepare occidiofungins, addresses the current, major limitation regarding moving 

occidiofungins forward for additional preclinical assessment, that is, the ability to access a highly pure 

occidiofungin to replace the mixtures that have heretofore been used. Aim 2 involves routine bioactivity 

assessment of the analogs, including in vitro activity (MIC and time-kill assays) and in vitro toxicity. 

There are many strengths to this application. The major strength of the proposal is the significance: the 

published and preliminary data suggest occidiofungins have very promising fungicidal activity with a 

distinct mechanism of action compared to known antifungals. Additionally, the occidiofungins do not 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 3	 ZRG1 BCMB-G (10)
 

SMITH, J 

appear have acute toxicity to mice at 20 mg/kg. A second strength of the application is the proposed 

multi-pronged approaches to access and prepare pure occidiofungin, which increases that likelihood 

that new analogs will be realized. At the end of the project, the identity of the active ingredient will be 

known and 2 complementary platforms will be in place for preparing pure occidiofungins and analogs, 

will be important for downstream experiments for identifying the target and further SAR studies when 

the target is in hand. There are a few minor weaknesses in the approach, specifically related to yields 

from the producing strain, under-developed semisynthesis and solid phase synthesis particularly with 

respect to the targeted structural modifications that will be pursued. Nonetheless, the productivity and 

experience of the applicant directly related to occidiofungins suggests the results will have a sustained 

influence in antifungal drug discovery. 

1. Significance: 

Strengths 

	 New antifungals with new modes of action and/or structures are desperately needed since 

relatively few options are clinically available. 

	 Occidiofungins have broad spectrum and potent antifungal activity, including against Candida 

species and Cryptococcus. 

	 Occidiofungin, a cyclic peptide, has a distinct structure relative to the other FDA-approved cyclic 

peptide antifungal, echinocandins. 

	 Scientific premise is well justified in the application and within the applicants publications on the 

topics. 

Weaknesses 

	 The lack of knowledge regarding the mechanism of action or having any results with a purified 

compound makes the analog generation project somewhat of a fishing expedition at this stage. 

2. Investigator(s): 

Strengths 

	 The PI has led the way in the isolation and characterization of occidiofungins, which have been 

documented in several high quality publications. 

Weaknesses 

	 None stated. 

3. Innovation: 

Strengths 

 Occidiofungins potentially represent an entirely new class of antifungal antibiotics.
 

 A genetic system in the producing strain has been demonstrated.
 

Weaknesses 

	 The screening is routine (although needed). 

4. Approach: 

Strengths 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 4	 ZRG1 BCMB-G (10)
 

SMITH, J 

	 Synergistic biosynthetic (genetic inactivation) and synthetic approaches are utilized to generate 

analogs. 

	 The utility of thioesterases (and potentially OcfN) to catalyze lactonization/lactamization has 

been demonstrated in other systems and is a powerful approach to access cyclized molecules. 

The premise for this approach is strongly supported by literature precedent and economic 

considerations. 

Weaknesses 

	 Genetic mutations will likely decrease the occidiofungin yields significantly as previously noted 

for the ocfC mutant. The applicant has also published the ocfN mutant and has an ocfD-TE 

domain mutant in-hand. Occidiofungin titres were never discussed or referenced within the 

proposal. 

	 Semisynthesis by chemical modification of the amine of DABA is only very briefly mentioned. 

What is the reaction condition? What are the target modifiers? How many analogs will be 

prepared and will the production levels be sufficient to support this endeavor? Another problem 

with this approach is that it will be presumably be performed with the mixture of occidiofungins, 

hence will give a mixture of products. 

	 The solid phase synthesis will potentially be more challenging than anticipated due to the 

unusual amino acid precursors (for example, β-hydroxy-Tyr and the fatty acid-like NAA2 

component) that will ultimately be needed to synthesize the natural product. 

5. Environment: 

Strengths 

	 The facilities are excellent. 

Weaknesses 

	 None stated. 

Protections for Human Subjects: 

Not Applicable (No Human Subjects) 

Vertebrate Animals: 

Not Applicable (No Vertebrate Animals) 

Biohazards: 

Not Applicable (No Biohazards) 

Authentication of Key Biological and/or Chemical Resources: 

Acceptable 

Budget and Period of Support: 

Recommended budget modifications or possible overlap identified: 

	 Possible overlap with 1R41AI122441-01A1 for "optimization of the production and isolation of 

the Novel antifungal occidiofungin". 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 5	 ZRG1 BCMB-G (10)
 

SMITH, J 

CRITIQUE 2: 

Significance: 1 

Investigator(s): 2 

Innovation: 2 

Approach: 2 

Environment: 2 

Overall Impact: Occidiofungin is a new cyclic nonribosomally synthesized antifungal peptide that kills a 

broad spectrum of fungi with submicromolar fungicidal activity. Occidiofungin has a novel mode of 

action and is a potent antifungal against fluconazole and caspofungin-resistant Candida albicans. This 

compound does not achieve fungus killing via inhibition of ergosterol production, binding to ergosterol 

or inhibiting the 1,3-β-glucan synthase enzyme, which are the current therapeutic targets for treating 

fungal infections. Thus it has a different mode of killing and worthy of further investigation. The PIs have 

applied for IP rights to this molecule and analogs thereof. Encouragingly, occidiofungin has minimal 

toxicity in mice dosed with 2 mg/kg in a 28 day toxicity study and at this dose, it was shown to reduce 

Candida glabrata load in the kidneys of infected mice. A limitation of occidiofungin however is that it is 

currently difficult to obtain pure analogs and the biological works have used mixtures of stereoisomers. 

Based on the favorable efficacy, alternative mode of action and safety profile of occidiofungin, the PIs 

aim to screen a library of natural and semi-synthetic analogs of occidiofungin (obtained via biosynthesis 

and chemical derivatizations) for bioactivity testing. Enthusiasm for this proposal is very high, although 

slightly tempered due to the difficulty of making the compounds, because occidiofungin could provide a 

solution to the incidence of drug-resistant agents. 

1. Significance: 

Strengths 

	 Occidiofungin has a novel mode of action and is a potent antifungal against fluconazole and 

caspofungin-resistant Candida albicans. 

Weaknesses 

	 It appears that it is difficult to obtain pure stereoisomer of occidiofungin and the difficulty in 

separating the components of the mixture or making large quantities of this compound could 

ultimately hamper commercial development of this compound. 

2. Investigator(s): 

Strengths 

	 The PIs have appropriate skills for this project. Importantly they have already provided some of 

the fundamental insights into occidiofungin activity (several publications) and they have filed a 

Composition and Methods of Use patent for occidiofungin (US 2011/0136729). 

Weaknesses 

	 None stated. 

3. Innovation: 

Strengths 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 6	 ZRG1 BCMB-G (10)
 

SMITH, J 

	 This compound does not achieve fungus killing via inhibition of ergosterol production, binding to 

ergosterol or inhibiting the 1,3-β-glucan synthase enzyme, which are the current therapeutic 

targets for treating fungal infections. 

Weaknesses 

	 None stated. 

4. Approach: 

Strengths 

	 Genetic modification and chromatographic separation could lead to pure stereoisomers of 

occidiofungin. 

	 The xylose moiety is not necessary for activity so the use of a mutant strain to make analogs 

without the xylose unit could be a fruitful endeavor. 

	 The PI’s plan to identify which analogs have optimal activity before expending resources to 

engineer B. contaminans MS14 strains. This is a rigorous strategy that will ensure that only the 

required strains are made. 

Weaknesses 

	 None stated. 

5. Environment: 

Strengths 

	 The environment is appropriate for proposed work. 

Weaknesses 

	 None stated. 

Protections for Human Subjects: 

Not Applicable (No Human Subjects) 

Vertebrate Animals: 

Not Applicable (No Vertebrate Animals) 

Biohazards: 

Not Applicable (No Biohazards) 

Authentication of Key Biological and/or Chemical Resources: 

Acceptable 

Budget and Period of Support: 

Recommend as Requested. 

CRITIQUE 3: 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 7	 ZRG1 BCMB-G (10)
 

SMITH, J 

Significance: 1 

Investigator(s): 2 

Innovation: 1 

Approach: 3 

Environment: 4 

Overall Impact: This is a proposal for the development of discoveries in Dr. Smith’s laboratories of an 

antifungal complex of compounds (occidiofungins). Extensive preliminary work has resulted in: (1) 

Determination of the biosynthetic pathways involved; (2) The ability to manipulate the pathways through 

genetic engineering; (3) Preliminary demonstration of a spectrum of antifungal activity highly 

competitive with existing agents; (4) Preliminary SAR data; and (5) An acceptable toxicity profile. Based 

on the extensive preliminary work development of an occidiofungin for the treatment of human fungal 

infections would be highly significant. The PI is highly qualified to carry out the proposed work. The 

level of innovation is also quite high and the approach proposed is logical. While the environment is 

sufficient for Phase I additional personnel and facilities would probably be needed to proceed to a 

Phase II submission and, eventually, an IND filing. 

1. Significance: 

Strengths 

	 The identification of a family of antifungal agents possessing low toxicity while having fungicidal 

properties against clinically significant pathogens is of very high significance. 

	 The investigators have done a large amount of excellent preliminary work that demonstrates 

that the occidiofungins possess these properties. 

	 They have determined the biosynthetic pathways involved and have demonstrated their ability 

to manipulate the same so as to gather structure activity relationship (SAR) data on the various 

components of the occidiofungin complex. 

	 This suggests that they will be able to prepare pure components so as to be able to select one 

for clinical development. It will also enable them to obtain additional patent protection with 

extended market. 

Weaknesses 

	 None stated. 

2. Investigator(s): 

Strengths 

	 Dr. Smith has done a great deal of work to put himself and coworkers in excellent position to 

advance this program to clinical trials. 

	 He has also picked up business experience in his relatively short career (MBA). The proposal 

reflects this in that he has laid out a highly logical path forward. 

Weaknesses 

	 As the project progresses into IND preparation the company will need to add preclinical/clinical 

development personnel. 

3. Innovation: 

Strengths 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 8	 ZRG1 BCMB-G (10)
 

SMITH, J 

	 The preliminary work reported has been quite innovative. 

Weaknesses 

	 None stated. 

4. Approach: 

Strengths 

	 Dr. Smith has laid out a highly logical plan for the exploration of the SARs for the occidiofungins 

and for the fine tuning of the fermentation processes so as to allow for production of a lead 

product in essentially pure state. 

Weaknesses 

	 Dr. Smith is overly pessimistic regarding the need for high levels of improvements in separation 

methods. In the experience of the reviewer these are problems that should be resolvable. In the 

final analysis the compounds could be made by total synthesis. 

	 Development of a mixture of compounds would be very difficult from a regulatory viewpoint. 

5. Environment: 

Strengths 

	 The environment for the phase I program is adequate. 

Weaknesses 

	 It would have helped had the PI supplied more information regarding the production methods, 

yields, and plans for fermentation scale up. 

	 A better description of the UT facilities should have been given. 

Protections for Human Subjects: 

Not Applicable (No Human Subjects) 

Vertebrate Animals: 

Not Applicable (No Vertebrate Animals) 

Biohazards: 

Not Applicable (No Biohazards) 

Authentication of Key Biological and/or Chemical Resources: 

Acceptable 

Budget and Period of Support: 

Recommend as Requested. 

THE FOLLOWING SECTIONS WERE PREPARED BY THE SCIENTIFIC REVIEW OFFICER TO 

SUMMARIZE THE OUTCOME OF DISCUSSIONS OF THE REVIEW COMMITTEE, OR REVIEWERS' 

WRITTEN CRITIQUES, ON THE FOLLOWING ISSUES: 
 

 

 

 

 

 

 

 

 

 

 

 

1 R41 AI131792-01 9 ZRG1 BCMB-G (10)
 

SMITH, J 

COMMITTEE BUDGET RECOMMENDATIONS: The budget was recommended as requested. 

Footnotes for 1 R41 AI131792-01; PI Name: smith, James 

NIH has modified its policy regarding the receipt of resubmissions (amended applications). 

See Guide Notice NOT-OD-14-074 at http://grants.nih.gov/grants/guide/notice-files/NOT-OD14-074.html. The impact/priority score is calculated after discussion of an application by 

averaging the overall scores (1-9) given by all voting reviewers on the committee and 

multiplying by 10. The criterion scores are submitted prior to the meeting by the individual 

reviewers assigned to an application, and are not discussed specifically at the review meeting 

or calculated into the overall impact score. Some applications also receive a percentile 

ranking. For details on the review process, see 

http://grants.nih.gov/grants/peer_review_process.htm#scoring.