Gritstone Bio, Inc. (NASDAQ:GRTS) has announced positive interim results from its Phase 2 study of GRANITE, a personalized cancer vaccine, in patients with advanced microsatellite stable colorectal cancer (MSS-CRC). The data, which included 104 patients, suggests a potential step forward in treating this cancer type with limited treatment options.
The interim analysis, cut as of August 19, 2024, evaluated 69 patients with metastatic MSS-CRC randomized to receive either the GRANITE vaccine in combination with immune checkpoint inhibitors or the standard of care. A majority of these patients had liver metastases. The study indicated a 21% relative risk reduction of disease progression or death for patients treated with GRANITE compared to the control group. Notably, 33% of GRANITE patients remained free of disease progression.
Enhanced Efficacy in Low ctDNA Patients
The vaccine's impact was more pronounced in patients with a low disease burden, as indicated by circulating tumor DNA (ctDNA) levels at study entry. In this subgroup, there was a 38% relative risk reduction of progression or death. Functional neoantigen-specific T cells were detected in all tested GRANITE patients, demonstrating immune responses.
Safety Profile and Future Plans
The safety profile of GRANITE was favorable, with no treatment discontinuations due to adverse events. The most common side effects were mild, flu-like symptoms typical of potent vaccines. Gritstone plans to discuss the progression-free survival (PFS) data with the U.S. Food and Drug Administration (FDA) to determine the next steps, which may include a Phase 2 or 3 trial using ctDNA levels as a selection criterion for eligibility.
Financial Considerations
Despite the encouraging clinical data, Gritstone faces financial challenges. The company's second-quarter report revealed a net loss of $23 million, with cash reserves of $62 million and $40 million in debt. Gritstone has engaged Raymond James as a financial advisor to explore strategic options. InvestingPro Tips indicate that the company is quickly burning through cash. Analysts anticipate a sales decline in the current year, despite three analysts revising their earnings upwards for the upcoming period.
