DALLAS, TX -- May 12, 2026 -- OS Therapies Inc. (NYSE: OSTX): Stonegate Capital Partners updates their coverage on OS Therapies Inc. (NYSE: OSTX). OS Therapies advanced materially through late-stage regulatory and commercialization preparation as OST-HER2 moved from Phase 2bsupported planning toward a more defined global approval pathway in recurrent, fully resected, pulmonary metastatic osteosarcoma. The key change is greater regulatory clarity: EMA initiated rolling review of the OSTHER2 Conditional Marketing Authorization dossier, while EMA and Australia’s TGA aligned on 3-year overall survival as the approvable efficacy endpoint. Management also positioned seroconversion biomarker data as supportive surrogate efficacy evidence, shifting the investment debate from early proof-of-concept toward execution across a dense 2026 catalyst calendar. Key milestones include 2.5-year OS data in mid-2Q26, FDA/MHRA meetings in 2Q26, Phase 3 initiation in Australia in 3Q26, 3-year OS data in early 4Q26, and a potential EMA CMA decision in 4Q26.
Pipeline/Biomarker Overview: OST-HER2 remains the lead asset and clear value driver, supported by positive Phase 2b data, a maturing biomarker package, and a regulatory strategy centered on U.S. Accelerated Approval and ex-U.S. conditional approvals. Importantly, OSTX filed a new patent application covering a treatment-emergent immune signature tied to Listeria-based immune activation, with management noting that 100% of Phase 2b patients who achieved 1-year event-free survival exhibited the signature and went on to achieve 2-year overall survival. We view the biomarker data as supportive rather than standalone, but it strengthens the mechanistic rationale for OST-HER2 and may help regulators evaluate accelerated access alongside maturing survival data. Beyond OST-HER2, OSTX continues to frame broader platform optionality through OST-504 in prostate cancer and OST-503 in NSCLC/pancreatic cancer, though these remain secondary to the near-term OST-HER2 approval cycle and potential PRV monetization.
Regulatory Advancements: The regulatory story has moved from preparation into active review. In addition to EMA rolling review, OSTX was selected for EMA’s Raw Data Pilot Program, received MHRA ATMP designation, and aligned with TGA on key non-clinical, CMC, safety, biomarker, and confirmatory Phase 3 design elements. EMA requested updated 2.5-year OS data in mid-2Q26 and 3-year OS data in early 4Q26, which management expects to complete the CMA submission. Market access work with NICE and EMA HTA processes has also begun, potentially narrowing the gap between approval and commercialization. If the timeline holds, OSTX could exit 2026 with a materially clearer regulatory and commercial path.
Financial Performance: The financial story remains milestone-driven. OSTX’s $5.25M offering, plus expected $4.0M of non-dilutive U.K. VAT/R&D funding, should support operations into 2027 and bridge key 2026 regulatory catalysts, though financing risk remains if timelines slip or Phase 3 spending rises. We continue to view a potential PRV as a meaningful approval-contingent valuation lever, with the latest public PRV transaction at $205M.
Valuation: We use a probability-adjusted Discounted Cash Flow Model when valuing OSTX. Our valuation model returns a valuation range of $9.56 to $11.93 with a midpoint of $10.59.
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SOURCE: Stonegate, Inc.
