Turnstone focuses cell therapy on high-need tumor indications

Turnstone Biologics is adjusting its phase 1 trial strategy for its leading tumor-infiltrating lymphocyte (TIL) therapy, known as TIDAL-01. The company has decided to narrow its focus, excluding cutaneous melanoma and breast cancer from its ongoing trials. TIDAL-01 has been part of two phase 1 trials, one of which is the STARLING study. This study is evaluating the therapy's effectiveness in treating breast cancer, colorectal cancer, and uveal melanoma. Another trial, conducted in collaboration with the H. Lee Moffitt Cancer Center and Research Institute, has been centered on cutaneous and non-cutaneous melanomas.

In its second-quarter earnings announcement, Turnstone Biologics outlined their revised clinical development strategy for TIDAL-01. The focus is now on three major unmet medical needs: colorectal cancer, head and neck cancer, and uveal melanoma. Consequently, the company has decided to deprioritize the development of TIDAL-01 for cutaneous melanoma and breast cancer.

The company shared some promising initial data from the first four colorectal cancer patients involved in the STARLING trial. Among these patients, one demonstrated a "deep and durable ongoing complete response." According to CEO Sammy Farah, Ph.D., these initial clinical signals, particularly the complete response observed in one patient, show deep and lasting anti-tumor activity. These results align with biological data that supports the company's core hypothesis of enriching tumor-reactive T cells in their selected TIL therapies.

Farah also mentioned that as the competitive profile of TIDAL-01 strengthens based on this initial clinical data, the company is prioritizing its development in solid tumor indications. Turnstone believes that this focus, especially on metastatic colorectal cancer, will allow them to differentiate their TIL technology and provide the most benefit to patients.

In financial terms, Turnstone Biologics, which went public through an $80 million IPO last year, reported having $62.4 million in funds as of the end of June. The company expects this amount to support their operations into the third quarter of 2025.