GSK’s cancer immunotherapy Jemperli (dostarlimab) received an accelerated FDA approval for advanced rectal cancer patients with a specific genetic signature, expanding beyond the drug’s initial endometrial cancer indication. The label expansion follows the company’s clinical development program in mismatch-repair biology-driven colorectal disease. For biopharma stakeholders, the approval adds a new on-label use case for a PD-1 axis antibody and underscores continued regulatory receptivity to biomarker-defined cancer populations. It also adds competitive intensity to the immunotherapy landscape in rectal cancer, where treatment selection increasingly hinges on tumor molecular features. While accelerated approvals can carry confirmatory obligations, the immediate commercial implication is clear: prescribers and payers will begin operationalizing a new genetic test workflow tied to access and reimbursement decisions.