Candel Therapeutics Inc. (NASDAQ: CADL) reported extended survival data from its phase 2a trial of aglatimagene besadenovec in patients with advanced non-small cell lung cancer who had inadequate response to immune checkpoint inhibitors.

The company said 50% of 46 patients treated with the experimental therapy survived beyond 24 months, with 35% surviving beyond 30 months and 13% exceeding 50 months of survival. These results represent an improvement from prior data showing 39% of patients alive at 24 months.

Among patients surviving beyond 24 months with available data, 85% had baseline PD-L1 tumor proportion scores below 50%, a population typically less responsive to immune checkpoint inhibitors. Median overall survival was 25.4 months in the per-protocol population and 21.5 months among patients with progressive disease at baseline despite prior immune checkpoint inhibitor therapy.

Post-treatment tumor biopsies showed increased pro-inflammatory gene expression associated with long-term survival, including significant increases in interferon signaling markers. The company also observed expansion of T-cell receptor repertoire diversity in both tumor tissue and peripheral blood following treatment.

The Food and Drug Administration has granted Fast Track designation for aglatimagene plus valacyclovir in combination with immune checkpoint inhibitor therapy for patients with stage III/IV non-small cell lung cancer resistant to first-line PD-(L)1 inhibitor therapy.

Candel plans to advance the program into a pivotal phase 3 clinical trial in patients with non-squamous non-small cell lung cancer, with trial initiation expected in the second quarter of 2026.

The company's experimental therapy involves intratumoral administration of a replication-defective adenovirus designed to deliver a gene that converts a prodrug into compounds that cause immunogenic cell death in proliferating cells. More than 1,000 patients have been dosed with aglatimagene in clinical trials.