Candel Therapeutics (CADL) Study result summary

Study background and objectives

• Prostate cancer remains a significant global health issue, with 1.4 million new cases in 2020 and a high unmet need for curative treatments that minimize recurrence and side effects.

• Extended follow-up data from a phase III trial of aglatimagene in intermediate to high-risk localized prostate cancer were presented at the 2026 AUA annual meeting.

• The trial aimed to assess if aglatimagene plus valacyclovir/prodrug with standard radiotherapy could reduce recurrence risk versus placebo, without significant added toxicity.

• Aglatimagene is a replication-defective adenoviral vector delivering HSV-TK to tumor cells, administered with an oral prodrug for local activation, enhancing immune priming and disease control.

• The trial was conducted under FDA special protocol assessment and received Fast Track and RMAT designations.

Study design and patient characteristics

• The study enrolled 745 patients, randomized 2:1 to aglatimagene or placebo, both with standard radiotherapy (with/without short-term ADT or prodrug).

• Randomization was stratified by NCCN risk group and planned short-course ADT.

• Median age was 69 years; 85% were White/Caucasian, and 74% had intermediate-risk disease.

• Primary endpoint was disease-free survival (DFS); key secondary endpoints included freedom from biochemical failure and metastasis.

• Total events at data cut: 147 (84 aglatimagene, 63 placebo), consistent with 2:1 randomization.

Key efficacy results

• Median follow-up of 58 months showed aglatimagene improved prostate-specific DFS by 39% in the intent-to-treat population (HR=0.61, p=0.0031).

• In the intermediate-risk subset (85% of patients), aglatimagene improved DFS by 41% (HR=0.59, p=0.0034), reduced time to salvage therapy by 49% (HR=0.51), and reduced time to biochemical failure by 52% (HR=0.48).

• Metastatic disease occurred in 0.24% of aglatimagene patients vs 2.35% in placebo; hazard ratio for time to metastasis was 0.1 in the intermediate-risk group.

• In the overall population, lower incidence and increased time to metastasis were seen in the aglatimagene arm (1.6% vs 2.8%, HR=0.58).

• Longer time to salvage anticancer therapy and biochemical failure was observed in the aglatimagene arm (HR=0.72 for both endpoints).