Resolute Science announced the U.S. FDA has granted Orphan Drug Designation (ODD) to its lead therapeutic, RS-5, for the treatment of soft tissue sarcomas. RS-5, a Macrophage-Targeted Conjugate (MAC-TAC), has shown profound single-agent anti-cancer activity and excellent tolerability across 22 preclinical studies, in 10 different tumor models. This regulatory milestone underscores RS-5's therapeutic potential and supports the company's continued progress toward initiating first-in-human clinical trials in 2026.
SAN DIEGO, Oct. 24, 2025 /PRNewswire-PRWeb/ -- Resolute Science, Inc., a preclinical-stage biotechnology company pioneering a novel class of pan-cancer therapeutics for aggressive, rare and metastatic solid tumors, announced today that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) to its lead asset, RS-5, for the treatment of soft tissue sarcomas.
The FDA grants Orphan Drug Designation to promote the development of promising treatments for rare diseases affecting fewer than 200,000 people in the United States. This regulatory milestone underscores RS-5's therapeutic potential and supports the company's continued progress toward initiating first-in-human clinical trials in 2026.
"Patients with sarcomas need and deserve better treatment options," said Faith H. Barnett, MD, PhD, Founder and CEO of Resolute Science. "Rare cancers make up about 25% of all cancers and are largely overlooked. Our pan-cancer Macrophage-Targeted Conjugate (MAC-TAC) platform may be particularly beneficial for these underserved patients."
Soft tissue sarcomas comprise a heterogeneous group of rare cancers with approximately 13,500 new cases diagnosed annually in the United States. Despite aggressive treatment with surgery, radiation, and chemotherapy, metastatic and recurrent sarcomas remain difficult to treat, with five-year survival rates often below 20%. Few targeted therapies are currently available, highlighting the urgent need for new approaches.
Orphan Drug Designation qualifies sponsors for incentives, including tax credits for qualified clinical trials, exemption from user fees, including New Drug Application (NDA), and a potential seven years of market exclusivity after approval.
About RS-5
RS-5 is a MAC-TAC carrying an MMAE (monomethyl auristatin E) payload for the treatment of solid tumors, including soft tissue sarcomas. In preclinical models, RS-5 has demonstrated profound single-agent anti-cancer efficacy across 22 studies, in 10 different tumor models, while being well tolerated. Resolute plans to file an Investigational New Drug (IND) application and initiate a first-in-human Phase 1 trial in 2026.
About Resolute Science
Resolute Science is advancing a pipeline of first-in-class synthetic drug conjugates for the treatment of aggressive, rare, and metastatic solid tumors. The modular design of its Macrophage-Targeted Conjugate (MAC-TAC) platform enables the rapid development of drug candidates to deliver a variety of targeted cytotoxic and radiotherapeutic payloads deep into tumors. Resolute's approach has the potential to overcome the resistance mechanisms associated with cancer-cell-targeting therapeutics. To learn more, please visit www.resolutescience.com.
Media Contact
Andre Basbaum, Resolute Science, Inc., 1 (858) 229-2627, [email protected], www.resolutescience.com
SOURCE Resolute Science, Inc.
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