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 was presented at the 2026 AUA annual meeting.

• The trial aimed to assess if aglatimagene plus valacyclovir 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 androgen deprivation therapy (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.

• Over 1,000 patients have been dosed in clinical trials, with a favorable tolerability profile.

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 prostate cancer-specific DFS by 41%, reduced time to salvage therapy by 49%, and reduced time to biochemical failure by 52%.

• Metastatic disease developed in 0.24% of aglatimagene patients vs 2.35% in placebo; hazard ratio for time to metastasis was 0.1 (90% improvement).

• Pathological complete response rates at two years were significantly higher with aglatimagene, suggesting eradication of cancer at the microscopic level.

• Consistent clinical benefit observed across secondary and exploratory endpoints, including time to biochemical failure, time to metastasis, and time to need for salvage anti-cancer therapy.