SBIR-STTR Award

Antitumor and anti-infectious disease vaccines require adjuvants in order to obtain optimal immunogenicity and therapeutic and protective efficacy. QS-21 is a natural saponin fraction that significantly out-performs other adjuvants in eliciting productive antibody and T-cell responses. It has remained the adjuvant of choice and has proven it's potency as immunological adjuvant in many cancer, infectious disease and degenerative disorder vaccine trials. Problems that have hampered the further development of QS-21 include adverse biological effects (that limit the tolerable dose), chemical instability, scarcity of the Quillaja saponaria tree (from which QS-21 is extracted) and variability of harvest yields from these trees. Recently, all of these liabilities have been overcome by our semisynthetic approach to QS-21 synthesis. This synthesis has also made molecular building blocks readily available for synthesis of modified and truncated QS-21 analogues. The replacement of unstable linkages within the native saponin with chemically robust functional groups has enhanced molecular stability. Structural variants incorporating systematic simplification of the peripheral sugar moieties and of the acyl chain substructure have aided in determining the minimal structural requirements for safety and potent adjuvant activity, and have decreased the required number of synthetic steps by over 50% from fully synthetic QS-21 (SQS-21) to our lead synthetic analogues. These efforts (now completed) have resulted in selection of the optimal QS-21 analogue TiterQuil-1-0-5-5 for more formal preclinical development because of its simplified structure, improved stability, consistent potency and attenuated toxicity. The core intellectual property is our Triterpene Saponin Synthesis Technology (TriSST) platform covering both the method of synthesis as well as novel compositions of matter under the patent application 'TRITERPENE SAPONINS, METHODS OF SYNTHESIS, AND USES THEREOF' application number 12/420,803 as well as our proprietary semisynthetic technology which is protected by US patent U.S. Patent No. 8,283,456. TriSST was developed by Dr. David Gin et al at Memorial Sloan-Kettering Cancer Center (MSKCC) and this technology has been exclusively licensed by Adjuvance Technologies, Inc. TriSST is a highly convergent synthetic approach in which the four domains in QS-21 (branched trisaccharide + triterpene + linear tetrasaccharide + fatty acyl chain) are synthesized separately and then assembled to produce the target molecule. Each of the domains can be modified independently and then combined to produce a virtually infinite number of rationally designed QS-21 analogs. Initially fully synthetic QS-21(SQS-21) was shown to be safe and immunologically active in a Phase 1 clinical trial. We then used TriSST to prepare and test over 100 novel analogues in a systematic sequential series of studies. Our model for evaluating QS-21 and analogues has involved KLH-conjugate vaccines against a series of peptide and carbohydrate cancer antigens, measurement of antibody responses against these antigens, and in some cases measurement of T-cell responses against MUC1 and KLH. Results in these several assays have tracked in parallel with no consistent outliers. The potency of selected analogues has been confirmed against novel Lyme fever OspC peptides and pneumococcal Prevnar 13 vaccines. Here we propose to further develop TiterQuil-1-0-5-5 for clinical use by scaling up synthesis in an independent facility. At the conclusion of these studies we will have demonstrated that TiterQuil-1-0-5-5 synthesis can be scaled up to near commercially required levels and that it has improved purity, stability, safety, ease of manufacture, and immunologic potency (using an expanded panel of antigens more relevant for infectious disease vaccines) when compared to natural or synthetic QS-21. This will provide the basis for a Phase 2 SBIR application supporting a TiterQuil-1-0-5-5 drug master file (DMF) and its wider use in vaccines that target diverse public health concerns. Specific Aim 1: Synthesize 2 grams of truncated QS-21 analogue TiterQuil-1-0-5-5, a sufficient quantity for Aims 2 and 3. Specific Aim 2: Confirm purity, stability and erythrolytic capacity of this scaled up batch of TiterQuil-1- 0-5-5, and perfrm a formal pharmacology/toxicology study as required for a DMF application. Specific Aim 3: Compare the immunologic potency and safety of TiterQuil-1-0-5-5 with natural and synthetic QS-21(SQS-21) using vaccines targeting OspC peptide as well as the commercially available pneumococcal conjugate Prevnar-13.

Thesaurus Terms:
Adjuvant;Analog;Antibodies;Antibody Formation;Antigens;Attenuated;Base;Biological;Biological Assay;Carbohydrates;Characteristics;Chemicals;Clinical;Communicable Diseases;Conjugate Vaccines;Degenerative Disorder;Design;Development;Disease;Dose;Fever;Functional Group;Harvest;Immunogenicity;Immunologic Adjuvants;Immunologics;Improved;Intellectual Property;Keyhole Limpet Hemocyanin;Lead;Legal Patent;Licensing;Malignant Neoplasms;Measurement;Memorial Sloan-Kettering Cancer Center;Methods;Modeling;Molecular;Mucin-1 Staining Method;Next Generation;Novel;Ospc Protein;Peptides;Peripheral;Pharmaceutical Preparations;Pharmacology And Toxicology;Phase;Phase I Clinical Trials;Pre-Clinical;Prevnar;Protective Efficacy;Public Health Medicine (Field);Public Health Relevance;Safety;Saponin;Saponins;Scale Up;Series;Small Business Innovation Research Grant;Soapbush;Structure;Sugar;T Cell Response;Technology;Testing;Toxic Effect;Treatment Efficacy;Trees;Trisaccharides;Triterpenes;United States;Vaccine Adjuvant;Vaccines;Vaccinology;Variant;

Vaccines against infectious diseases continue to improve public health across the world. With increased knowledge of etiologic pathogens and necessary immune responses have come increasingly safe and defined or targeted vaccines. The success of defined vaccines requires use of an immunological adjuvant to permit more effective immunization. Few adjuvants have sufficient potency and acceptable toxicity for clinical use, restricting the potency of some vaccines and requiring higher or more doses of others. A leading adjuvant candidate is the natural product QS-21 which has been used in numerous clinical settings despite 3 major liabilities: dose limiting toxicity, poor stability, and limited availability of quality product. To address these liabilities, supported by RO1s at Memorial Sloan-Kettering Cancer Center (MSKCC), we developed new synthetic strategies that permitted synthesis of QS-21 and purposefully engineered QS-21 analogs. Adjuvance Technologies Inc. is a privately held biopharmaceutical company formed to bring the potential of this synthetic saponin technology to clinical fruition. This technology has permitted systematic modification of the separate chemical domains of QS-21 for increased tolerability and immunological potency. Adjuvance has licensed and patented this technology and used it to design analogues with improved potency/toxicity ratios compared to QS-21 while decreasing the required number of synthetic steps. TiterQuil-1-0-5-5 (1055) was selected as optimal and the focus of our Phase I SBIR application from over 100 rationally designed Adjuvance molecules. In 1055 each of the 3 major QS-21 liabilities has been eliminated. Work accomplished under the Phase I SBIR demonstrated that our selected CMO, Albany Molecular Research Inc. (AMRI), was able to prepare 1055 in batches as large as 600 mgs and that these batches had the requisite purity and diminished toxicity demonstrated previously with smaller batches prepared in laboratories at MSKCC. Finally these batches of 1055 continued to surpass QS-21 in augmenting antibody titers against a variety of antigens in the absence of the toxicity seen with QS-21. The goals of this Phase II SBIR application are to perform the steps required for wider preclinical use and to generate the data necessary to complete an Investigational New Drug (IND) application to the U.S. FDA. If production of consistently pure, stable, safe and widely effective material at scale is successful in the work proposed here, Adjuvance plans to distribute 1055 widely to collaborators and under separate funding conduct a Phase I clinical trial with acellular pertussis vaccine plus 1055. We address here the concerns raised by potential commercial partners, as well as BARDA, DoD and the NIH: commercial scalability and cost, possible toxicity, and applicability to use with more widely used immunological carriers and antigens. These will all be addressed as we take the steps necessary to be able to conduct the initial Phase I clinical trial with 1055.

Public Health Relevance Statement:
PROJECT NARRATIVE Currently available immunological adjuvants have insufficient potency or unacceptable toxicity, restricting the potency of many vaccines and requiring higher or more doses of others. In this Phase II SBIR, Adjuvance Technologies will demonstrate that NCSS batches of its semi-synthetic saponin adjuvant TiterQuil-1-0-5-5 (1055) can be inexpensively prepared and that its potency and safety with a variety of antigens remains unmatched. Once this is confirmed, 1055 could be used to augment the potency of the majority of standard commercial vaccines as well as a range of experimental vaccines investigated at BARDA, DoD, the NIH, and internationally.

Project Terms:
Address; Adjuvant; aluminum sulfate; analog; Antibody Response; Antibody titer measurement; Antigen Targeting; Antigens; biodefense; Biological Products; Biopharmaceutics; Chemicals; Chemistry; Clinical; commercial application; commercialization; Communicable Diseases; cost; Data; design; Development; Diphtheria Toxin; Dose; Dose-Limiting; Effectiveness; Elderly; Engineering; Etiology; Fruit; functional hypothalamic amenorrhea; Funding; Goals; Hemagglutinin; Hepatitis A; Hepatitis B; Hepatitis C; Human Papillomavirus; Immune response; Immunization; immunogenicity; Immunologic Adjuvants; Immunologics; improved; Industry; interest; International; Investigational Drugs; Knowledge; Laboratories; Legal patent; Licensing; Malignant Neoplasms; Memorial Sloan-Kettering Cancer Center; Modification; Molecular; Natural Products; next generation; pathogen; pertactin; Pertussis; Pertussis Toxin; Pertussis Vaccine; Pharmacology and Toxicology; Phase; Phase I Clinical Trials; pre-clinical; Production; programs; Public Health; QS21; Rationalization; Readiness; Research; S Phase; Safety; Saponins; Small Business Innovation Research Grant; success; Technology; Testing; Tetanus Toxin; Toxic effect; United States National Institutes of Health; Vaccine Adjuvant; Vaccine Antigen; Vaccines; Work