Gritstone Bio's GRANITE Shows Promise in Colorectal Cancer Treatment
Gritstone Bio Inc. (GRTS) recently announced promising interim Phase 2 data for its individualized neoantigen-targeting immunotherapy, GRANITE, in the treatment of frontline microsatellite-stable colorectal cancer (MSS-CRC). The study evaluated the clinical benefit of GRANITE in combination with immune checkpoint inhibitors and standard chemotherapy compared to standard chemotherapy alone.
The data revealed that GRANITE demonstrated a 21% relative risk reduction of progression or death across all treated populations compared to the standard of care control group. Notably, the greatest benefit was observed in patients with lower disease burden at study entry, as measured by circulating tumor DNA (ctDNA). In this subgroup, GRANITE showed a 38% relative risk reduction of progression or death compared to the control group.
Based on these results, Gritstone plans to discuss the progression-free survival (PFS) data with the FDA and determine the next steps for advancing GRANITE, including potential Phase 2 or 3 trials using ctDNA levels as eligibility criteria.
While the data suggests potential for GRANITE in treating MSS-CRC, analysts remain cautious. Some highlight the limited benefit observed in the overall population and the lack of significant investor excitement. Others acknowledge the promising technology behind GRANITE but see limited paths forward for substantial share price increases.
Following the announcement, GRTS stock experienced a significant decline, dropping 57.5% to $0.25 per share. This drop reflects the mixed market response to the data and the uncertainty surrounding GRANITE's future development.