OS Therapies Inc DEFA14A, filed Oct 17, 2025
OS Therapies Inc (OSTX)
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): October 14, 2025
OS THERAPIES INCORPORATED
(Exact name of registrant as specified in its charter)
| Delaware | 001-42195 | 82-5118368 | ||
| (State or other jurisdiction of incorporation) |
(Commission File Number) | (IRS Employer Identification No.) |
| 115 Pullman Crossing Road, Suite 103 Grasonville, Maryland |
21638 | |
| (Address of Principal Executive Offices) | (Zip Code) |
Registrant’s telephone number, including area code: (410) 297-7793
N/A
(Former name or former address, if changed since last report.)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):
| ☐ | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| ☒ | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
| ☐ | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| ☐ | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities registered pursuant to Section 12(b) of the Act:
| Title of Each Class | Trading Symbol(s) | Name of Each Exchange on Which Registered | ||
| Common Stock, par value $0.001 per share | OSTX | NYSE American |
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☒
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
CURRENT REPORT ON FORM 8-K
OS Therapies Incorporated
October 14, 2025
Item 7.01. Regulation FD Disclosure.
On October 17, 2025, OS Therapies Incorporated (the “Company”) posted an investor presentation to its website at ir.ostherapies.com. The information on the Company’s website is not incorporated by reference into this Current Report on Form 8-K. The Company expects to use the investor presentation, in whole or in part, and possibly with modifications, in connection with presentations to investors, analysts and others. A copy of this investor presentation is furnished as Exhibit 99.1 to this Current Report on Form 8-K.
The information in this Item 7.01 is being furnished pursuant to Item 7.01 of Form 8-K. In accordance with General Instruction B.2. of Form 8-K, the information in this Item 7.01, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as may be expressly set forth by specific reference in such a filing.
Item 8.01. Other Events.
Annual Meeting Adjournment
On October 14, 2025 at 10:00 a.m., Eastern time, the Company convened its 2025 annual meeting of stockholders (the “Annual Meeting”) virtually. The proposals submitted to the Company’s stockholders for approval at the Annual Meeting are described in the definitive proxy statement filed with the Securities and Exchange Commission (the “SEC”) on August 25, 2025 (the “Proxy Statement”). Based on the preliminary tabulation of votes received, the Issuance Proposal, the Charter Amendment Proposal and the Auditor Ratification Proposal (each as defined in the Proxy Statement) received the requisite votes for approval. However, the Company adjourned the Annual Meeting in order to allow additional time to solicit proxies. The adjourned Annual Meeting will reconvene at 10:00 a.m., Eastern time, on October 21, 2025. The reconvened Annual Meeting will still be held in a virtual meeting format accessible at https://meeting.vstocktransfer.com/OSTHERAPIESOCT25. The close of business on August 20, 2025 will continue to be the record date for the determination of stockholders of the Company entitled to vote at the reconvened Annual Meeting.
Stockholders may vote at the reconvened Annual Meeting or by submitting a proxy for the reconvened Annual Meeting. Stockholders of the Company who have previously submitted their proxy or otherwise voted and who do not want to change their vote do not need to take any action. During the period of the adjournment, the Company will continue to solicit votes from its stockholders with respect to the proposals for the Annual Meeting.
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The Company encourages all stockholders of record as of the close of business on August 20, 2025, who have not yet voted, to do so by October 20, 2025 at 11:59 p.m., Eastern time. Notwithstanding the foregoing, any votes properly received before the close of the reconvened Annual Meeting on October 21, 2025 will be accepted. Proxies previously submitted in respect of the Annual Meeting will be voted at the reconvened Annual Meeting unless properly revoked.
Additional Information and Where to Find It
This document may be deemed to be solicitation material in respect of the Annual Meeting to be reconvened on October 21, 2025. The Company previously filed the Proxy Statement on August 25, 2025. BEFORE MAKING ANY VOTING DECISIONS, STOCKHOLDERS ARE URGED TO READ THE PROXY STATEMENT AND ANY OTHER RELEVANT DOCUMENTS FILED BY THE COMPANY WITH THE SEC, BECAUSE THEY CONTAIN IMPORTANT INFORMATION ABOUT THE RECONVENED ANNUAL MEETING. The Proxy Statement has been made available to stockholders who are entitled to vote at the Annual Meeting. No changes have been made in the proposals to be voted on by stockholders at the Annual Meeting. The Company’s Proxy Statement and any other materials filed by the Company with the SEC can be obtained free of charge at the SEC’s website at www.sec.gov.
Participants in the Solicitation
The Company and its directors and executive officers and other employees may be deemed to be participants in the solicitation of proxies in respect of the reconvened Annual Meeting.
Item 9.01 Financial Statements and Exhibits.
(d) Exhibits.
| Exhibit Number |
Description | |
| 99.1 | Investor Presentation – OS Therapies Incorporated. | |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |
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SIGNATURE
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
| OS THERAPIES INCORPORATED | |||
| Dated: October 17, 2025 | By: | /s/ Paul A. Romness, MPH | |
| Name: | Paul A. Romness, MPH | ||
| Title: | President and Chief Executive Officer | ||
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Exhibit 99.1
NYSE American: OSTX Corporate Presentation October 2025
NYSE American: OSTX 2 Safe Harbor Statement This document contains forward - looking statements . In addition, from time to time, we or our representatives may make forward - looking statements orally or in writing . We base these forward - looking statements on our expectations and projections about future events, which we derive from the information currently available to us . Such forward - looking statements relate to future events or our future performance, including : our financial performance and projections ; our growth in revenue and earnings ; and our business prospects and opportunities . You can identify forward - looking statements by those that are not historical in nature, particularly those that use terminology such as “may,” “should,” “expects,” “anticipates,” “contemplates,” “estimates,” “believes,” “plans,” “projected,” “predicts,” “potential,” or “hopes” or the negative of these or similar terms . In evaluating these forward - looking statements, you should consider various factors, including : our ability to change the direction of the Company ; our ability to keep pace with new technology and changing market needs ; and the competitive environment of our business . These and other factors may cause our actual results to differ materially from any forward - looking statement . Forward - looking statements are only predictions . The forward - looking events discussed in this document and other statements made from time to time by us or our representatives, may not occur, and actual events and results may differ materially and are subject to risks, uncertainties and assumptions about us . We are not obligated to publicly update or revise any forward - looking statement, whether as a result of uncertainties and assumptions, the forward - looking events discussed in this document and other statements made from time to time by us or our representatives might not occur . Risks Related To Our Business Our business is subject to a number of risks you should be aware of before making an investment decision . These risks include the following : • Our success is primarily dependent on the successful development, regulatory approval and commercialization of our lead product candidates which are in the early stages of development • Our approach to the discovery and development of innovative products is novel, and unproven and may not result in marketable products • We have no source of predictable revenue, have incurred significant losses since inception, may never become profitable and may incur substantial and increasing net losses for the foreseeable future as we continue the development of, and seek regulatory approvals for our product candidates • If clinical trials of our product candidates fail to demonstrate safety and efficacy, we may be unable to obtain regulatory approvals to commercialize our product candidates • We are subject to regulatory approval processes that are lengthy, time - consuming and unpredictable . We may not obtain approval for any of our product candidates from the FDA or foreign regulatory authorities • Even if we obtain regulatory approval, the market may not be receptive to our product candidates • We may not be able to establish collaborative partnerships with other pharmaceutical companies, through which we expect to complete development of, obtain marketing approval for and, if approved, manufacture and market our product candidates • We may encounter difficulties satisfying the requirements of clinical trial protocols, including patient enrollment • We may face competition from other companies in our field or claims from third parties alleging infringement of their intellectual property
NYSE American: OSTX 3 OS $1.2B Breast Cancer $35B Cancer Immunotherapy $126B Investment Highlights Over $300 million has been invested in listeria platform to date, mostly by Advaxis/Ayala (OS acquired all listeria - based asset s in April 2025) Platforms Total Addressable Market Near - Term Catalytic Milestones OST - HER2: Listeria monocytogenes (Lm): • Ultra Orphan Lead Clinical Program in Osteosarcoma (OS) with follow - on applications in breast cancer and other solid tumor cancers • The total addressable market (or “TAM”) for these assets and follow - on applications are $258B TAM OST - Lm platform represents new cancer immunotherapy category: cervical cancer, non - small cell lung, GBM, prostate, etc. OST - tADC: • Next - gen Tunable Drug Conjugate (or “tADC”) Unique Patented Silicone linker improves safety and efficacy Human Osteosarcoma: $1.2B Expected US topline revenue for OST - HER2 in osteosarcoma: $500M+ Canine Osteosarcoma: $150M+ Cancer Immunotherapy: Meetings with FDA/MHRA/EMA & subsequent BLA & MAA submissions for OST - HER2 in Human Osteosarcoma – December ’25 – March ‘26 Regulatory pathway for OST - HER2 in Canine Osteosarcoma & spinoff – Q4/25 – Q1/26 FDA Accelerated Approval – Q2/Q3 2026 Priority Review Voucher (or “PRV”) – Upon FDA Accelerated Approval • Most recent sale $160M (Abeona, June 2026) • Rare Pediatric Disease Designation (RPDD) granted by FDA • Orphan Designation & Fast Track Designation granted by the FDA & EMA Market and Financial Summary Stock Price: [$1.87] Shares Outstanding: [~34M] Market Cap: [$60M] Cash: [~$4M] Monthly Cash Burn: [~$300K] Timing of Accelerated FDA Approval and PRV: April - September 2026 Estimated PRV Sale Proceeds: [~$160M]
NYSE American: OSTX 4 Clinical - Stage Pipeline (Listeria Platform) Trial Preclinical Phase 1 Phase 2a Phase 2b Phase 3 Approval Launched Osteosarcoma (OS) (OST - HER2) HPV Cancers (OS) (OST - AXLA) Non - Small Cell Lung Cancer* (NSCLC) (OST - 503) Non - Small Cell Lung Cancer* (NSCLC) (OST - 503) Globlastoma (GBM) (OST - 503) Breast Cancer (BC) (OST - HER2) Prostate Cancer* (PC) (OST - PSA) Canine (OS) (OST - HER2) Positive Phase 2b Data. Targeting Accelerated Approval Q2 - Q3/26 Completed Phase 3a Data: Pending data release and Phase 3b trial Metastatic disease alone & in combi w/Keytruda Frontline alone & in combo w/Keytruda Glioblastoma alone & in combo Keytruda HER2+ BC in Combination w/HER2 Abs Biochemically Recurrent Disease USDA conditional approval achieved. Full approval path pending updated regulatory guidance ✔ Orphan drug designation ✔ Fast Track Designation ✔ Rare Pediatric Disease Designation Lead Program Phase 1b Data Q4/25
NYSE American: OSTX 5 Preclinical Pipeline (Listeria & ADC Platform) 5 Trial Preclinical Phase 1 Phase 2a Phase 2b Phase 3 Approval Launched Ovarian Cancer (OST - tADC) Breast Cancer (OST - tADC) Other Solid Tumors (OST - tADC) Solid Tumors (8 undisclosed OST - Lm therapeutic candidates)
OST - HER2: Human & Canine Osteosarcoma + Other Human Cancers
NYSE American: OSTX 7 Department Of Pediatric Hematology, Oncology And Blood & Marrow Transplantation Peter M. Anderson, MD Scientific Advisory Board for Osteosarcoma Assistant Professor, Department Of Pediatrics, Section Of Hematology - Oncology, Baylor College Of Medicine Meenakshi Hedge, MD Associate Professor, Department Of Pediatrics, Section Of Hematology - Oncology, Baylor College Of Medicine Nabil M. Ahmed, MD Pediatric Malignancies - Cancer Genetics - Associate Professor Of Pediatrics Alejandro S. Cordero, MD Professor, Division Of Pediatric Hematology And Oncology - Masonic Cancer Center Brenda Weigel, MD Orthopedics Surgery - Musculoskeletal Oncology Felafsa M. Wodajo, MD
NYSE American: OSTX 8 Commercialization and Partnerships OS Patient Advocacy Antibody Drug Conjugates (ADCs) Commercialization Miriam Cohen Mother of OS Angel Serena Subada Osteosarcoma Patient Mac Tichenor Father of OS Angel Olivia Egge Osteosarcoma Patient Tony Trent Father of OS Angel OST - HER2 Trial Participant Recent Features and Partnerships Dr. Jutta Wanner Founding Scientist Dr. Borys Shor President & CEO Dr. Colin Goddard Founding Scientist Chris Benecchi Chief Business Officer Scott Styles Managing Partner Edward Robb, DVM Chief Strategy Officer https://www.youtube.com/watch?v=8wWeaGKT3A k https://www.youtube.com/watch?v=z2YLhT3bb1 Q
NYSE American: OSTX 9 9 Preclinica l Phase 1 Phase 2b Osteosarcoma (Bone Cancer) No Treatments Available to Prevent or Delay Subsequent Recurrences Global Death Rate Upon Recurrence/Metastasis is 80 - 90% Crompton et al: Survival after recurrence of osteosarcoma: A 20 - year experience at a single institution. August 2005: Pediatric Blood & Cancer. https://onlinelibrary.wiley.com/doi/abs/10.1002/pbc.20580 Osteosarcoma (“Bone Cancer”) is a solid tumor of the bone: • 1,000 cases/year in US; 20,000 globally • Most Cases Present In Patients 15 - 20 Years Of Age • No New Treatments In Over 40 Years • METS (Lung) In ~40 - 50%+ Of Patients: 400 to 500 patients • High Lung METS Recurrence: Fatality Rate: ~ 90% @ 5 years, 40% @ 2 years • Time To Mortality Upon METS Recurrence: ~12 Months • Only Treatment for Recurrent METS: Lung METS Surgery o No drug therapy used (chemotherapy/Keytruda/Herceptin etc all failed) • Objective = Prevent Recurrence - Increase Overall Survival Standard of Care (or “SOC”): • Primary OS – a) Amputation of leg, extremity b) orthopedic implant and highly toxic 9 - month chemotherapy regimen with10% treatment - associated mortality • Secondary OS / Recurrent Disease: None
NYSE American: OSTX 10 Preclinica l Phase 1 Phase 2b Osteosarcoma Micro - Metastasis Lymphocytes (T - Cells) OST - HER2 leverages antigen presentation to drive attack on metastases
NYSE American: OSTX 11 OST - HER2 Open Label Phase 2b Trial Enrollment Criteria • 12 - 39 years old • Recurred, resected metastatic (METS) Osteosarcoma • 39 evaluable patients at 21 centers, single treatment arm – FULL TREATMENT ARM COMPLETE • 52 Weeks on Study: Dosed 16 times every 3 weeks for 48 weeks with 4 - week follow - up final visit • Primary Endpoint : 12 - month Event Free Survival (EFS) vs. Children’s Oncology Group (COG) publication • Secondary Endpoint : Overall Survival (OS) • Exploratory Endpoint #1 : 12 - month EFS vs. Natural History Case Matched Database • Exploratory Endpoint #2 : OS vs. Leaving Publication Exploratory Endpoint - Natural History Case Matched Database: Only Database Currently Available in US • Patient Advocacy Group Collected under IRB (n=55) • Many didn’t meet the stringent enrollment criteria outlined above or had missing key data points (n=46) • Only 9 evaluable subjects
P - Value Published Historical Control (n=42) OST - HER2 Treated Group (n=41) 0.0196 20% 35% (n = 40 evaluable, 1 lost to follow - up) Primary Endpoint:12 month EFS <0.0001 40% 75% (n = 36 evaluable, 5 lost to follow - up) Secondary Endpoint: 2 - year OS 100% Subgroup: OS in =>12month EFS 59% Subgroup: OS in < 12 month EFS P - Value Male Female 0.0604 20% 47% Primary Endpoint:12mo EFS 1 st Resection 2+ Resections 0.0848 25% 55% Primary Endpoint: 12mo EFS P - Value Within 2+ Resections: Prior to Study Within 2+ Resection: On study 0.1945 27% 55% Primary Endpoint: 12mo EFS OST - HER2 Clinical Data in Recurrent, Resected Metastatic Osteosarcoma Timeline – Strategy: Overall Survival + Biomarkers Milestones to Accelerated Approval (US) & Conditional Approval (UK/EMA) December 2025 UK MHRA Pre - MAA Meeting (2 - year overall survival + biomarker correlation) December 11, 2025 US FDA Type C Meeting (2 - year overall survival + biomarker correlation) December 2025 EMA SAM Meeting (2 - year overall survival + biomarker correlation) December 2025 UK MHRA MAA Filing for Approval (2 - 3 month review after filing) January 2026 US FDA BLA Filing for Approval (3 - 6 month review after filing) Q1/2026 EMA MAA Filing for Approval (3 - 6 month review after filing)
NYSE American: OSTX 13 OST - HER2 Canine Osteosarcoma Program University of Pennsylvania Veterinary School (UPenn Vet) Regulatory Pathway Positive proof - of - concept data post - resection: Published • Able to distinguish responders with biomarkers • Treatment response, as measured by immune markers, can improve with more doses o New study planned to evaluate continued dosing Positive proof - of - concept data limb sparing (pre - resection): Publication in progress • Strong treatment response w/ 8 doses • Immune markers improved with more doses • Preparing for Meeting with USDA to review new manufacturing process for reactivation of conditional approval (Q4/2025, subject to gov’t shutdown) • Company intends to launch under conditional approval in 2026 • Company will sponsor confirmatory trial at UPenn Vet to support full approval, expected in 2026 3: Immunological responses and clinical outcomes in dogs with osteosarcoma receiving standard therapy and a Listeria vaccine exp ressing HER2, Mason, Nicola J. et al., Molecular Therapy, Volume 0, Issue 0 Design
NYSE American: OSTX 14 OST - HER2 Breast Cancer Treatment Positive Preclinical & Phase 1 Results > Anticipate 2025 Phase 2 Trial – $30B TAM Preclinical Studies • In nonclinical studies, OST31 - 164 was found to cause regression of tumors in both a spontaneous HER2 - expressing tumor model and in a metastatic breast cancer model in mice • The reduction in tumor growth with OST31 - 164 was directly associated with the induction of HER2 - specific immune responses • HER2 - specific CD8 T - cell responses are elicited by OST31 - 164 Phase 1 Trial Endpoints Met Study Design • Late stage advanced/metastatic HER2 expressing solid tumors (n=12) Primary • Dose limiting toxicity for OST31 - 164 o Determined therapeutic dose: 1x10⁹ CFU Secondary • Efficacy signals o One patient left hospice care following treatment
NYSE American: OSTX 15 Animal Data: Inhibition of Growth of Breast Cancer Tumors Treatment Model Mouse Models of Breast Cancer • The first figure on the right is a treatment model • The second figure on the right is a prevention model The first figure shows Lm - LLO - chHER2 (OST - HER2 component) Anti - tumor activity against a foreign antigen of an established tumor in female FVB/N mice. The NT - 2 tumor cell line was derived from a spontaneous mammary tumor in a rat HER2/neu transgenic FVB/N mouse and therefore expresses rat HER2. Prevention Model
NYSE American: OSTX 16 The Combination of OST - HER2 + HER2 Antibody (e.g. Herceptin, et al) shows strong improvement vs. HER2 Antibody alone (PBS + HER2 Ab) * Lm - LLO - (XXX) = OST - HER2 component OST - HER2+ HER - 2/neu Ab Combo Shows Stronger Efficacy Than HER - 2/neu Ab Alone
NYSE American: OSTX 17 Suppression of Growth of Metastatic Breast Cancer in the Brain Delay of Breast Cancer Growth in the Brain To determine whether OST - could inhibit the growth of a metastatic breast cancer in the brain, BALB/c mice (n=4 animals/ group) were administered 5 × 10^8 CFU of OST - HER2 or Lm control by intraperitoneal injection once a week for three weeks. After the third injection, mouse breast carcinoma EMT6 cells stably transfected with luciferase (EMT6 - Luc) were injected into the brains of anesthetized mice (5000cells/mouse). Tumor growth was detected in all control animals but none of the OST - HER2 treated animals.
NYSE American: OSTX 18 OST - HER2 Additional Cancer Clinical Targets Bladder, Breast Cancer, other HER2+ solid tumors OST - HER2 plus trastuzumab may prevent development of trastuzumab resistance in HER2+ solid tumors like Bladder, Breast, others https://doi.org/10.1016/S1470 - 2045(07)70190 - 0 Solid Tumor Treatment Potential – Combined $35B TAM HER2+ Solid Tumors Rationale: OST - HER2 + trastuzumab may prevent development of trastuzumab resistance in HER2+ gastroesophageal cancer and extend utility of trastuzumab after first progression https://dx.doi.org/10.1186%2Fs13045 - 019 - 0737 - 2 Esophageal Rationale: 2 - 3% are HER2+, ICI have not been active in CRC except in DNA Mismatch Repair where there is high T cell infiltration Trastuzumab and lapatinib – 30% response rate in HER2 + CRC Increasing T cell infiltration with OST31 - 164 may improve activity of ICI in CRC, especially HER2+ CRC https://ascopubs.org/doi/full/10.1200/PO.19.00154 Colorectal HER2 positivity across cancers: analysis of 37,992 samples by IHC. IHC 3+ was considered HER2 IHC positive Yan, M., Schwaederle, M., Arguello, D. et al. HER2 expression status in diverse cancers: review of results from 37,992 patients. Cancer Metastasis Rev 34, 157 – 164 (2015). https://doi.org/10.1007/s10555 - 015 - 9552 - 6 Yan, M., Schwaederle, M., Arguello, D. et al. HER2 expression status in diverse cancers: review of results from 37,992 patie nts . Cancer Metastasis Rev 34, 157 – 164 (2015). https://doi.org/10.1007/s10555 - 015 - 9552 - 6
NYSE American: OSTX 19 OST - Lm Platform Additional Immunotherapy Candidates • AIM2SERV Trial Completed: 1st of 2 Phase 3 clinical trials needed for approval • Phase 3a trial completed • Phase 3b trial Solid Tumor Treatment Potential – Combined $35B TAM OST - AXAL (HPV Cancers) • Positive NSCLC data in frontline in combination with Keytruda and Keytruda salvage • Positive NSCLC data in metastatic disease OST - 503 (NSCLC & Glioblastoma) • Positive interim Phase 1b/2a prostate cancer data in castration resistant population • Single site study at Columbia: enrollment paused with potential to restart enrollment OST - 504
NYSE American: OSTX 20 OST - tADC Linker Platform tADCs / tSM - DCs /tmRNA - DCs
NYSE American: OSTX 21 OST - tADC Product Overview • “Plug & Play” - Targeting Ligands, pH sensitive SiLinkersTM (silicon linkers), and multiple CAPed (Conditionally Active) Payloads • Antibodies (ADC), small molecules (SM - DC) and mRNA therapeutics (mRNA - DC) Potential to Displace Legacy Cancer Chemo Treatment Interchangeable Ligands, Linkers, and Payloads: Tunable Drug Conjugate • A platform technology with extensive flexibility and multiple licensing opportunities – without limiting OS Therapies therapeutic development • Currently in pre - clinical studies and working toward 2 - Week & GLP toxicity trials • Phase 1 trials for ovarian cancer are expected to begin in 2025 OST - tADC Program
NYSE American: OSTX 22 OST - tADC PLATFORM IS “PLUG AND PLAY” AND “ADAPTABLE” Modular Approach is a Key Differentiator - Preferred Building Block Examples
NYSE American: OSTX 23 CHEMICAL MODIFIERS ALLOW TUNABLE SiLINKERS CLEAVAGE Payload Release can be Tuned to Occur Either in Endosome or Lysosome Key Points: • Proximal functional groups influence the hydrolysis rate of the silicone linkers • We have demonstrated that rapid hydrolysis with the pyrimidine system in vitro translated to rapid linker cleavage in cells Linkers which cleave more rapidly under slightly acidic conditions are ideal for small OST - TDC approach Stable SiLinkers can be used in ADCs to raise the Drug - to Antibody Ratio (DAR) to between 6 and 24 payloads per ADC LCMS Hydrolysis studies were carried out in 50 mM HEPES buffer (pH 7.4 or pH 5) at 37 ° C
NYSE American: OSTX 24 tADC Patented Silicon Linkers Design Patented OST SiLinker Pioneering Next - Gen ADCs Next - Gen Silicone LINKER Traditional GGFG LINKER Traditional VAL - CIT LINKER +++ + + % Payload at Released at Target Tumor Site YES Limited NO Stability in Circulation YES NO NO New IP for Old Payloads NO YES – Macrophages YES – Ubiquitous Premature Cathespin Cleavage NO NO YES Myelosuppresion YES NO NO Multiple Payloads per Linker
Corporate Overview
NYSE American: OSTX 26 Paul Romness, MHP President & CEO - OS Therapies Robert Petit, PhD Chief Medical & Scientific Officer Founding Scientist: OST - HER2 Jutta Wanner, PhD Advisor Founding Scientist: OST - tADC Gerald Commissiong Chief Business Officer Management Team - 100+ Years of Experience Deep Pharmaceutical Experience And Successful Track Records 100+ Years Combined Experience > 20 Product Launches > 10 Licensing Deals Global Sales • 25 years of experience in the biopharma • Johnson & Johnson • Amgen • Boehringer Ingelheim • 9 major product launches: • Oncology, surgery, HIV, FSD, COPD, IPF, CV & diabetes • Masters of Health Policy from George Washington University Medical Center & B.S. in Finance from American University • Inventor & Founding Scientist behind OS Therapies’ clinical - stage listeria cancer vaccine platform • Large Pharma Experience: BMS, & Pharmacia • Small Pharma Experience: MGI Pharma (Acquired by Otsuka), Advaxis, SARS Therapeutics, RGP Biotech & Orionis Biosciences • MD from Ohio State University College of Medicine & BS in Life Science from Indiana State University • Research interests: Oncology & Virology • 15 years of experience in biopharma • Small Pharma Experience: Amarantus Bioscience Holdings, Avant Diagnostics, Todos Medical • Specializes in M&A, Capital Raising, Strategic Planning and Investor Relations • Therapeutic areas: Oncology, Neurology, Immunology and Regenerative Medicine • BS in Management Science & Engineering from Stanford University • Inventor & Founding Scientist behind OS Therapies’ tunable Drug Conjugate (tDC) platform (tADC, tSMDC and tmRNADC) • Large Pharma Experience: Roche • Small Pharma Experience: BlinkBio • PhD from the University of Kansas w/ postdoc training at The Scripps Research Institute in San Diego • Research interests: Oncology & Virology Paul Romness was inspired to launch OS Therapies following the Osteosarcoma diagnosis of a close family friend $35B+ Revlimid $20B+ Spiriva $30B+ Epoetin Alfa $25B+ Retuxin $30B+ Herceptin $20B+ Pradaxa $20B+ Yervoy $8B+ Jardiance
NYSE American: OSTX 27 Preclinica l Phase 1 Phase 2b Key Takeaways Catalyst Rich Advanced OST - HER2 Cancer Therapeutic Platform • Phase 2b trial for OST - HER2 in Osteosarcoma positive data: Announced Jan 2025 • Path to Pivotal OST - HER2 Canine OS study to support full approval pending USDA alignment: 2H/25 • End of Phase 2 FDA Meeting: Aug 27, 2025 • BLA Submission: Q3/25 • Accelerated Approval: Q4/25 - Q2/26 • TAM Human Osteosarcoma – $1.2B • Market Opportunity for OST - HER2 in Osteosarcoma: $500M • TAM Canine Osteosarcoma – $150M+ • tADC platform – $311 billion • Osteosarcoma (Human and Animal): No new approvals in 40+ years • Orphan, Fast Track, Rare Pediatric Disease Designations granted by the FDA and EMA for OST - HER2 • Priority Review Voucher – if OST - HER2 approved, PRV value = $150M • Proven management team with large & early - stage pharma experience with multiple successful product launches • Expert OS scientific advisory board • Strong patient advocacy & commercialization advisors • Cash on hand into mid - 2026 Multiple Near - Term Clinical Milestones Significant Market Opportunity Favorable Regulatory Review Process Experienced, Successful Leadership
Thank You! Paul Romness President & CEO par@ostherapies.com (703) 541 - 9811 Investor Relations Harrison Seidner, PhD WaterSeid Partners OSTX@waterseid.com Public Relations Stephanie Chen Elev8 New Media stephanie@elev8newmedia.com