In this interview, Paul Peter Tak, President & CEO of Candel Therapeutics, offers a deep dive into the company’s viral immunotherapy platform, CAN‑2409, its strategic development journey, and how disruptive science is reshaping prostate cancer care.
What makes CAN-2409 unique
AN‑2409 is not a traditional oncolytic virus but a viral-mediated in vivo gene therapy. A replication-defective adenovirus delivers the HSV‑tk gene directly into the tumor.
Patients receive oral valacyclovir, which the HSV‑tk enzyme converts into a toxic agent, causing local cell death and releasing tumour antigens-triggering a CD8+ T-cell–mediated immune response, both locally and systemically.
This in situ “vaccination” approach harnesses each patient’s unique tumor antigen profile for a finely targeted immune response.
Competitive Advantage & Platform Strength
Unlike checkpoint inhibitors, which induce broad immune activation, CAN‑2409 is patient-specific and off-the-shelf, offering precision without complex personalized manufacturing.
The therapy is supported by preclinical proof-of-concept and data from Phase 2a and Phase 3 trials in prostate, NSCLC, pancreatic, and glioblastoma settings.
As Tak explains, viruses are “very good at delivering genes to cells”, leveraged here to initiate potent inflammation and immune activation at tumour sites.
Phase 3 Results & Regulatory Momentum
CAN‑2409 achieved its primary endpoint in the Phase 3 PrTK03 trial, showing a 30% reduction in disease recurrence or death (HR ~0.70; p=0.0155) in prostate cancer patients when combined with radiation versus radiation alone.
38% reduction in prostate cancer-specific recurrence or death (HR ~0.62; p=0.0046).
80% of treated patients reached pathological complete response at two years, compared to ~64% in the control arm.
Safety profile remains favorable, with no new safety signals identified and mostly mild, self-limited adverse events like flu-like symptoms and fever.
CAN‑2409 has received FDA Fast Track and RMAT designations, and the Phase 3 protocol was aligned under a Special Protocol Assessment (SPA).
The company anticipates filing a BLA by Q4 2026 with expedited review opportunities via FDA pathways.
Company Resilience & Strategic Agility
Facing financial strain in late 2023, Candel took decisive measures, staff and manufacturing cuts, to extend its runway and reach key clinical milestones.
Despite those hardships, Phase 3 data success triggered a 200% surge in stock price, followed by a $92M public offering that fueled ongoing development efforts.
Tak emphasizes disciplined investment, avoiding premature manufacturing scale-up until impactful clinical data emerged, preserving resources for high-probability programs.
