Turnstone Biologics Corp. (TSBX) saw its stock price take a hit on Thursday after the company released initial data from its Phase 1 STARLING trial of TIDAL-01 in metastatic microsatellite-stable colorectal cancer (MSS mCRC). TIDAL-01 is a tumor-infiltrating lymphocyte therapy, a promising approach that leverages the body’s own immune system to fight cancer.
The trial results showed positive signs. Among the four evaluable patients, Turnstone observed a 25% overall response rate (ORR) and a 50% disease control rate (DCR). One patient achieved a complete response, which has been sustained for over a year. The therapy demonstrated the ability to generate and expand T cells that targeted specific cancer antigens, leading to a significant increase in CD8 T cell infiltration within the tumors.
The TIDAL-01 treatment was also well-tolerated, with side effects consistent with the known risks associated with the lymphodepletion regimen and the administration of IL-2 and pembrolizumab.
While the initial data is encouraging, Turnstone has decided to shift its clinical development strategy for TIDAL-01, focusing on three high-need indications: colorectal cancer, head and neck cancer, and uveal melanoma. The company has deprioritized cutaneous melanoma and breast cancer.
The STARLING trial is currently enrolling patients with these three prioritized indications. Turnstone has a solid financial position with $62.4 million in cash and short-term investments as of June 30, 2024, which is projected to support operations into the third quarter of 2025.
Despite the positive trial data, the TSBX stock price took a significant dip, dropping by 57.53% to 93 cents at publication on Thursday. This decline suggests that investors may be cautious about the company’s shift in focus and the overall market sentiment for biotechnology stocks.
The future of TIDAL-01 remains bright. The promising initial data suggests the potential for this innovative therapy to benefit patients struggling with cancer. The ongoing clinical trials will be crucial in determining the full potential of TIDAL-01 and its impact on the treatment landscape.
