CAN-2409 is an innovative viral immunotherapy designed to treat prostate cancer by inducing immunogenic cell death in tumors and activating the immune system to target cancer cells. This therapy utilizes a replication-defective adenovirus to deliver the herpes simplex virus thymidine kinase (HSV-tk) gene directly into tumor cells. When combined with the antiviral medication valacyclovir, the therapy selectively destroys cancer cells while stimulating an immune response against the tumor.

In a Phase 3 trial involving 745 patients with intermediate- to high-risk localized prostate cancer, CAN-2409 was combined with valacyclovir and standard external beam radiation therapy. The results showed a 14.5% relative improvement in disease-free survival (DFS) at 54 months compared to radiation therapy alone. Additionally, the treatment led to a 30% reduction in the risk of disease recurrence or death, marking a significant advancement in prostate cancer care.

The therapy was also associated with favorable safety outcomes, with adverse effects largely limited to mild flu-like symptoms, confirming its tolerability. These results represent a major milestone, as CAN-2409 could offer a new therapeutic option for patients who are at increased risk of recurrence and are currently limited to standard radiation therapy.

CAN-2409 works through a dual mechanism:

1. Direct Tumor Destruction: Tumor cells infected with the HSV-tk gene are sensitized to valacyclovir, leading to cell death.
2. Immune Activation: The destruction of tumor cells releases antigens that trigger a robust immune response, potentially targeting cancer cells systemically.

This combination of local and systemic effects not only controls the primary tumor but also mobilizes the immune system to reduce the risk of recurrence or metastasis.

Following the success of the Phase 3 trial, Candel Therapeutics plans to seek regulatory approval for CAN-2409, with efforts to expand its use in prostate cancer and potentially other cancer types. Recruitment for additional studies may begin soon to explore further applications of this therapy.

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