At the 2025 ASCO Annual Meeting in Chicago (May 30–June 3), Candel Therapeutics presented the results from its pivotal Phase 3 trial of CAN‑2409 (aglatimagene besadenovec) combined with valacyclovir and standard radiotherapy for intermediate‑to‑high‑risk localized prostate cancer.
Dr. Theodore DeWeese delivered the oral presentation on June 3, 2025, in the Genitourinary Cancer session at McCormick Place.
Key clinical findings
Primary Endpoint Met
Addition of CAN‑2409 reduced the risk of recurrence or death by 30% (Hazard Ratio 0.70; p=0.0155) in the intent‑to‑treat population (496 treated vs. 249 placebo)lation (496 treated vs. 249 placebo).
Secondary Insights
- DFS benefit observed both with and without short‑term androgen deprivation therapy (ADT).
- When focusing on prostate‑specific survival (excluding other‑cause deaths), risk reduction reached 38% (HR 0.62; p=0.0046).
- PSA nadir (<0.2 ng/mL) achieved in 67.1% of the CAN‑2409 group versus 58.6% in placebo (p=0.0164).
- At two‑year biopsies, 80.4% of patients on CAN‑2409 exhibited pathological complete response, compared to 63.6% with placebo (p=0.0015)
Safety Profile
Adverse events were generally mild. Serious events occurred in 1.7% (CAN‑2409) vs. 2.2% (placebo). Common side effects included flu‑like symptoms, fever, and chills.
What is Can-2409?
CAN‑2409 is an off‑the‑shelf, replication‑deficient adenovirus engineered to deliver the HSV‑tk gene directly into tumors. Upon administration of valacyclovir, HSV‑tk converts it into a toxic metabolite, destroying nearby cancer cells and triggering an individualized systemic CD8+ T‑cell immune response. With over 1,000 doses administered to date, it has shown a favorable safety profile across multiple tumor types. The drug has FDA Fast Track designation for localized prostate cancer, PDAC, and ICI‑resistant NSCLC, plus Orphan Drug status for PDAC. Its prostate phase 3 study was conducted under a Special Protocol Assessment (SPA) with the FDA.
Implications & Next Steps
- This is the first multicenter randomized Phase 3 trial in over 20 years to meet both primary and secondary endpoints in this prostate cancer setting—potentially redefining treatment for intermediate‑to‑high‑risk patients.
- Candel plans to submit a Biologics License Application (BLA) for CAN‑2409 by Q4 2026.
- Beyond prostate cancer, CAN‑2409 is being evaluated in NSCLC and borderline-resectable PDAC, where prior phase 2a results also showed promising survival outcomes.
- A conference call on June 3, 2025 featured commentary from leading prostate cancer experts (Drs. Sylvester and Tutrone) who helped contextualize real‑world implications of the data.
https://t.co/6s7m3YEPaU
