FDA Grants Fast Track Designation to Insilico Medicine’s AI-Designed ISM6331 for Advanced Mesothelioma

Insilico Medicine has secured U.S. Food and Drug Administration (FDA) Fast Track Designation (FTD) for ISM6331, an investigational pan-TEAD inhibitor generated using the company’s proprietary artificial intelligence platform, for the treatment of adults with unresectable malignant pleural mesothelioma whose disease has progressed after anti-PD-1 antibody therapy, with or without anti-CTLA-4 therapy, and platinum-based chemotherapy. The designation marks the first Fast Track recognition for a drug candidate developed through Insilico’s AI-driven pipeline.

FDA Fast Track Supports Accelerated Clinical Development

Fast Track Designation is intended to accelerate the development and regulatory review of therapies that address serious diseases with significant unmet medical needs. The designation provides more frequent interactions with the FDA throughout development and may allow eligibility for Rolling Review, Priority Review, and Accelerated Approval if regulatory requirements are met.

For ISM6331, the designation follows FDA Orphan Drug Designation granted in June 2024 for malignant pleural mesothelioma, further reinforcing regulatory support for the program. Under the Rolling Review pathway, completed sections of a future New Drug Application (NDA) can be submitted and reviewed before the full application is finalized, potentially shortening overall review timelines.

AI-Designed Pan-TEAD Inhibitor Targets the Hippo Signaling Pathway

ISM6331 is a novel, non-covalent pan-TEAD inhibitor discovered using Chemistry42, Insilico Medicine’s generative chemistry platform. The investigational therapy targets dysregulated Hippo signaling, a pathway that contributes to tumor growth, proliferation, and survival in multiple cancers.

By inhibiting TEAD activity, ISM6331 is intended to restore Hippo pathway regulation. Preclinical studies demonstrated broad antitumor activity, potent efficacy at low doses, favorable absorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics, and a favorable safety profile. The candidate also showed synergistic antitumor activity and the potential to overcome treatment resistance when combined with other anticancer therapies.

Malignant pleural mesothelioma remains an aggressive cancer with limited treatment options after progression on immunotherapy and platinum-based chemotherapy, highlighting the need for additional therapeutic approaches.

Phase I Clinical Development Continues

Clinical evaluation of ISM6331 is underway in a global multicenter Phase I first-in-human trial that enrolled its first patient in January 2025. While efficacy results have not yet been reported, initial Phase I clinical data have been accepted for a brief oral presentation at the European Society for Medical Oncology (ESMO) Congress 2026, reflecting growing scientific interest in the program.

The current Fast Track Designation enables closer collaboration with the FDA on trial design, biomarker strategies, and broader development planning as the study progresses.

Leadership Highlights Clinical and AI Innovation

Halle Zhang, PhD, Vice President of Clinical Development–Oncology at Insilico Medicine, said the Fast Track Designation reinforces confidence in ISM6331 following encouraging preclinical findings and ongoing Phase I progress. She noted the therapy’s potential as both a single agent and combination treatment because of its synergistic antitumor activity and ability to address drug resistance.

Feng Ren, PhD, co-Chief Executive Officer and Chief Scientific Officer, said the designation validates the potential of Chemistry42-generated drug candidates and supports the company’s strategy of integrating generative AI into drug discovery. He added that regulatory mechanisms such as Fast Track can help accelerate development of innovative therapies for patients with limited treatment options.

Future Development

With both Orphan Drug and Fast Track Designations in place, Insilico Medicine is positioned to advance ISM6331 through clinical development with enhanced regulatory engagement. The company will continue enrolling patients in the ongoing Phase I study while preparing to present first-in-human clinical data at ESMO 2026. Future development is expected to evaluate the therapy both as monotherapy and in combination regimens, while taking advantage of expedited FDA review pathways if emerging clinical evidence supports further advancement.

Reference

Insilico Medicine Receives FDA Fast Track Designation for ISM6331, the AI-driven Pan-TEAD Inhibitor, in Advanced Mesothelioma