Candel Therapeutics Receives FDA Regenerative Medicine Advanced Therapy Designation for CAN-2409 for the Treatment of Prostate Cancer

Candel Therapeutics, Inc. recently announced the US FDA has granted Regenerative Medicine Advanced Therapy (RMAT) designation to CAN-2409 (aglatimagene besadenovec), the company’s biological immunotherapy lead candidate, for the treatment of newly diagnosed localized prostate cancer in patients with intermediate-to-high-risk disease. CAN-2409 was also previously granted FDA Fast Track designation for the same indication.

The FDA’s RMAT designation is intended to expedite the development and review of regenerative medicine therapies intended to treat, modify, reverse, or cure serious or life-threatening diseases where preliminary clinical evidence indicates that the drug has the potential to address unmet medical needs for such disease or condition. The designation provides opportunities for intensive FDA guidance and organizational commitment to potentially support and expedite drug development. The designation also offers eligibility for mechanisms designed to speed Biologics License Application (BLA) review and approval, with potential opportunities for rolling review and priority review.

The RMAT designation was granted on the basis of the positive data from Candel’s phase 3 randomized, placebo-controlled clinical trial evaluating the efficacy and safety of CAN-2409 plus valacyclovir (prodrug), together with standard of care (SoC) external beam radiation therapy, in newly diagnosed, localized, intermediate-to-high-risk prostate cancer.

Data announced by Candel in December 2024 showed that the phase 3 trial met its primary endpoint and demonstrated statistically significant improvement in disease-free survival (DFS) (p=0.0155) with a 30% reduction (HR 0.70) in the risk for prostate cancer recurrence or death due to any cause in patients who received CAN-2409 plus prodrug, combined with SoC radiotherapy (n=496), compared with patients who received placebo combined with SoC radiotherapy (n=249). CAN-2409 improved prostate-specific DFS with a 38% risk reduction compared with placebo (HR 0.62; p=0.0046). There was also a significant increase in the proportion of patients achieving a prostate-specific antigen (PSA) nadir of <0.2 ng/ml in the CAN-2409 treatment arm compared to the placebo arm (67.1% vs. 58.6%, respectively; p=0.0164). Furthermore, the data showed an 80.4% pathological complete response in the 2-year post-treatment biopsies after CAN-2409 administration compared to 63.6% in the control arm (p=0.0015). The safety profile of CAN-2409 was generally consistent with previous studies, with no new safety signals identified. Key aspects of the study design, including the primary endpoint, were agreed with the FDA under a Special Protocol Assessment (SPA).

“Receiving the FDA’s RMAT designation underscores the critical unmet need in patients with early, localized prostate cancer and validates the promising clinical activity observed with CAN-2409. This designation further supports the design of our phase 3 study, including the DFS primary endpoint agreed upon with the FDA during the SPA negotiation,” stated Paul Peter Tak, MD, PhD, FMedSci, President and Chief Executive Officer of Candel.

Dr. Tak continued, “We look forward to collaborating with the FDA to pursue an expeditious approval of CAN-2409 once we submit our BLA—currently anticipated at the end of 2026. Our aim is to introduce a new treatment option for patients at the early stages of prostate cancer, a disease that has seen minimal innovation over the past two decades. We expect the RMAT designation to facilitate the BLA filing process and bring us closer to achieve this objective.”

CAN-2409 (aglatimagene besadenovec), Candel’s most advanced multimodal biological immunotherapy candidate, is an investigational, off-the-shelf, replication-defective adenovirus designed to deliver the herpes simplex virus thymidine kinase (HSV-tk) gene to a patient’s specific tumor. HSV-tk is an enzyme that locally converts orally administered valacyclovir into a nucleotide analog that kills nearby cancer cells. Together, this regimen is designed to induce an individualized and specific CD8+ T cell-mediated response against the injected tumor and uninjected distant metastases for broad anti-tumor activity, based on in situ immunization against a variety of tumor antigens. Because of its mechanism of action, CAN-2409 has pan solid tumor treatment potential. Encouraging monotherapy activity as well as combination therapy activity with standard of care radiotherapy, surgery, chemotherapy, and immune checkpoint inhibitor (ICI) treatment, have previously been shown in several preclinical and clinical settings. More than 1,000 patients have been dosed with CAN-2409 with a favorable tolerability profile to date, supporting the potential for combination with standard of care, when indicated.

Candel has recently completed a successful phase 3 clinical trial of CAN-2409 in localized prostate cancer and positive phase 2a clinical trials of CAN-2409 in non-small cell lung cancer (NSCLC) and borderline resectable pancreatic ductal adenocarcinoma (PDAC). CAN-2409 plus prodrug (valacyclovir) has been granted Fast Track Designation by the FDA for the treatment of PDAC, stage III/IV NSCLC in patients who are resistant to first line PD-(L)1 inhibitor therapy and who do not have activating molecular driver mutations or have progressed on directed molecular therapy, and localized primary prostate cancer. CAN-2409, plus prodrug, has also been granted Regenerative Medicine Advanced Therapy (RMAT) designation by the FDA for the treatment of newly diagnosed localized prostate cancer in patients with intermediate-to-high-risk disease. Candel’s pivotal phase 3 clinical trial in prostate cancer was conducted under a SPA agreed with the FDA. The FDA has also granted Orphan Drug Designation to CAN-2409 for the treatment of PDAC.

Candel is a clinical stage biopharmaceutical company focused on developing off-the-shelf multimodal biological immunotherapies that elicit an individualized, systemic anti-tumor immune response to help patients fight cancer. Candel has established two clinical stage multimodal biological immunotherapy platforms based on novel, genetically modified adenovirus and HSV gene constructs, respectively. CAN-2409 is the lead product candidate from the adenovirus platform; CAN-3110 is the lead product candidate from the HSV platform and is currently in an ongoing phase 1b clinical trial in recurrent high-grade glioma. Finally, Candel’s enLIGHTEN Discovery Platform is a systematic, iterative HSV-based discovery platform leveraging human biology and advanced analytics to create new viral immunotherapies for solid tumors. For more information, visit www.candeltx.com