FDA Fast Track Designation (FTD) aims to accelerate the review process of high-value assets, and ISM6331 marks Insilico’s first FTD, recognizing the clinical potential in advanced mesothelioma.
ISM6331 is a novel, potential best-in-class, pan-TEAD inhibitor engineered via Chemistry42 to restore Hippo pathway balance, and its Phase I first-in-human data has been accepted for a brief oral presentation at ESMO 2026.
The FTD grants ISM6331 enhanced FDA engagement to accelerate the clinical development processes, alongside eligibility for Rolling Review, Accelerated Approval, and Priority Review, if relevant criteria are met.

CAMBRIDGE, Mass., July 29, 2026 /PRNewswire/ — Insilico Medicine (“Insilico”; HKEX: 3696), a clinical-stage generative artificial intelligence (AI)-driven drug discovery company, today announced that ISM6331, a novel, potential best-in-class pan-TEAD inhibitor driven by Insilico’s proprietary AI, has received Fast Track Designation (FTD) from the U.S. Food and Drug Administration (FDA), for the treatment of adult patients with unresectable malignant pleural mesothelioma whose disease has progressed on or after prior treatment with anti-PD-1 antibody therapy, with or without anti-CTLA-4 antibody therapy, and platinum-based chemotherapy.

According to the FDA’s relevant policy, Fast track is a process designed to facilitate the development, and expedite the review of drugs to treat serious conditions and fill an unmet medical need. This is the first Fast Track Designation granted to a program in Insilico’s AI-driven pipeline, recognizing ISM6331’s potential to provide a meaningful therapy where limited options exist or to offer improved clinical efficacy over available treatments. Previously, ISM6331 received Orphan Drug Designation (ODD) for the same indication in June 2024, following the ODD in February 2023 for Rentosertib (ISM001-055), Insilico’s lead program currently in Phase III clinical trial for the treatment of idiopathic pulmonary fibrosis (IPF).

With the Fast Track Designation, ISM6331 gains access to regulatory benefits designed to streamline its clinical development path, including enhanced FDA engagement represented by more frequent meetings and written feedback regarding clinical trial design, biomarker strategies, and overall development plans. Additionally, subject to meeting the relevant criteria, the program may qualify for Accelerated Approval, Priority Review and Rolling Review process. Under the Rolling Review process, completed sections of a Biologic License Application (BLA) or New Drug Application (NDA) may be submitted to FDA for review as they become available, rather than waiting for the entire application to be completed.

“Receiving Fast Track Designation validates the strong clinical potential of ISM6331, and that is a boost to our confidence in it, on top of promising preclinical results and Phase I first-in-human progresses,” said Halle Zhang, Ph.D., Vice President, Clinical Development – Oncology at Insilico Medicine. “Moreover, ISM6331 boasts synergistic anti-tumor effects and potential to overcome drug resistance as combination therapy. We hope to work even more closely with the FDA as we accelerate clinical evaluation of ISM6331 for future development.”

ISM6331 is a potential best-in-class pan-TEAD inhibitor nominated in Jun 2023, with its novel scaffold empowered by Chemistry42, Insilico’s proprietary generative chemistry platform. Chemistry42 utilized structure-based drug design strategies to design novel molecules, which were subsequently prioritized through its advanced scoring and reward pipelines.

“Through pan-TEAD inhibition, ISM6331 holds best-in-class potential by aiming to restore balance to the Hippo pathway and prevent the proliferation and survival of tumor cells, and we’re proud to see the Chemistry42-driven candidate has its value recognized by the regulatory authorities with both ODD and FTD,” said Feng Ren, PhD, co-CEO and Chief Scientific Officer of Insilico Medicine. “At Insilico, we are delivering strategies to revolutionize drug R&D at scale, and the generative AI advantage in efficiency is largely maintained or even enhanced through innovation-friendly schemes like the FTD. We will always be open for global partnership and regulatory support to accelerate our clinical development momentum, and bring this innovative AI-driven option, among others, to patients in urgent need.”

Due to the novel scientific rationale and promising first-hand data in preclinical or clinical studies, ISM6331 was previously featured in AACR 2024 Annual Meeting, and its initial Phase I first-in-human clinical data has been accepted for a brief oral presentation at the upcoming ESMO 2026 Congress.

About ISM6331

ISM6331 is a potent pan-TEAD inhibitor, which not only effectively targets tumors with abnormalities in the hippo pathway but also shows synergistic anti-tumor effects and overcomes drug resistance in combination therapy. The novel, non-covalent structure of ISM6331 was guided by Chemistry42’s structure-based drug design strategy.

In preclinical studies, ISM6331 demonstrated broad anti-tumor efficacy, potent activity at low doses, and a favorable safety profile with favorable ADMET characteristics. In June 2024, ISM6331 was granted Orphan Drug Designation (ODD) by the FDA for the treatment of mesothelioma. In January 2025, the first patient was dosed in the global multicenter Phase I trial of ISM6331. In July 2026, ISM6331 received FDA Fast Track Designation.

About Insilico Medicine

Insilico Medicine is a pioneering global biotechnology company dedicated to integrating artificial intelligence and automation technologies to accelerate drug discovery, drive innovation in the life sciences, and extend health longevity to people on the planet. The company was listed on the Main Board of the Hong Kong Stock Exchange on December 30, 2025, HKEX:3696.

By integrating AI and automation technologies and deep in-house drug discovery capabilities, Insilico is delivering innovative drug solutions for unmet needs including fibrosis, oncology, immunology, pain, and obesity and metabolic disorders. Additionally, Insilico extends the reach of Pharma.AI across diverse industries, such as advanced materials, agriculture, nutritional products and veterinary medicine. For more information, please visit www.insilico.com.

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