Year: 2025
ASCO 2025: Candel CEO shares Phase 3 prostate cancer data on off-the-shelf immunotherapy.
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.
Bridging clinical practice and biotech.
Former GSK immunology leader Paul Peter Tak, MD PhD FMedSci, now President & CEO of Candel Therapeutics, sits down with Mike Rea (CEO of IDEA Pharma) to discuss the art and science of biotech leadership, R&D reinvention, and viral immunotherapy strategy.
From Clinic to C-Suite: A Career Reframed
Tak reflects on his early career as a rheumatologist and translational scientist, highlighting the importance of bridging real-world clinical insight with laboratory innovation. His pivot from GSK to a public biotech leader was driven by the ambition to reshape drug development through agility and creativity.
He shares lessons drawn from over two decades in immunology, noting that success often hinges less on mechanistic breakthroughs and more on multidisciplinary teamwork, rigorous decision‑making, and strategic portfolio choices.
Reimagining R&D
While at GSK, Tak led global immunology efforts, recognizing that long timelines and bureaucratic inertia often slowed innovation. At Candel, his goal is to run leaner, faster, and with more nimbleness. The approach, sometimes called “RxD”, combines combines clinical insight upfront with flexible trial design and early collaboration across functions like development, regulatory, and commercial.
He emphasises that R&D success comes from managing a balanced portfolio—some high-risk, potential blazers; others are “bread and butter” assets. But speed of learning and disciplined go/no-go decisions remain central.
Viral Immunotherapy & Value Creation
A major focus of the discussion is viral immunotherapy, exemplified by Tak’s leadership of CAN‑2409 at Candel. Rather than chasing broad blockbuster molecules, he advocates for tailor‑made biologics with defined mechanisms and targeted clinical populations. Such niche therapies may offer robust efficacy and clear clinical value, enabling better alignment between pricing, access, and real outcomes.
Tak also highlights the importance of value creation in biotech: measuring impact not only by scientific novelty but also by meaningful benefit to patients, investors, and health systems.
Crafted Leadership & Trust
Throughout the interview, Tak stresses leadership qualities that sustain high‑performing biotech organisations:
Transparency and trust
He fosters open lines between leadership, scientific teams, and stakeholder – even amid uncertainty.
Balanced decision-making
Encourage curiosity, but don’t tolerate endless indecision, discern when to pivot or kill programs early.
Interdisciplinary culture
Break down silos – encourage scientists to think about commercial, regulatory, clinical aspects of their work.
He points to real-world cases at Candel where efficient decisions expedited trial progress and investor confidence.
Key takeaways
- Clinical foundations matter, leading with patient insight leads to more meaningful therapeutic innovation.
- R&D needs creativity and speed-lean teams, early clinical collaboration, and rapid go/no-go steps are essential.
- Therapies with focus can create disproportionate value-like targeted viral immunotherapies in defined patient populations.
- Leadership is about trust, transparency and decisiveness – nurturing autonomy while setting high standards.
- Portfolio management is strategic, calibrating risk, potential and impact rather than betting solely on unicorn science.
The Mindful Leadership Podcast
In this inaugural Season 3 episode, Dr. Paul Peter Tak, MD PhD FMedSci, shares his journey from rheumatologist and academic to biotech leader, framed by a central purpose: to transform cancer care with truly impactful medicine.
In this episode, Tak reflects on key themes that define mindful leadership, resilient innovation, and scientific courage.
From Clinic to CEO
Tak starts by revisiting his early medical calling—treating patients first-hand in Amsterdam—which shaped his values around translational science. He credits a pivotal mentor whose guidance helped pivot his career from academia into executive roles at GSK, where he became Head of Immunology and Global R&D portfolio lead. At GSK, he cultivated the “Immunology Network,” a strategic bridge between pharma and academic research.
Why Candel?
Tak chose Candel Therapeutics for its agility and mission alignment. He recounts how the company nearly got delisted from NASDAQ before refocusing on signature assets like CAN‑2409, a viral immunotherapy showing promising results in prostate, lung, and pancreatic cancers, even in chemo or radiation-resistant cases. The episode delves into how patient impact, not incremental metrics—shaped the turnaround strategy and investor confidence.
A “Bloody-Obvious Test” in Innovation
A core philosophy Tak shares is the “Bloody Obvious Test”: innovation must deliver material benefit, not just statistical significance. He pushed early clinical trials in experimental medicine to deliver dense, high-quality data, even with small patient cohorts, to rapidly learn whether a therapy could genuinely transform lives. This discipline enabled early program termination and resource reallocation, when clinical outcomes didn’t align with molecular targets.
Reframing Failure as Fuel for Growth
In a candid segment, Tak discusses a failure he’s proud of: the shutdown of the ribbon kinase development program at GSK. Despite excellent chemistry and target engagement, the trial lacked meaningful patient outcomes. By stopping it early, he preserved credibility, resources, and focus for more promising programs. He mentors others to see failure not as defeat but as opportunity, an essential part of innovation and self-discovery.
The Mindful Leadership Challenge
Tak offers a reflective challenge to leaders: “Could you do what you do today in a fundamentally different way? Not for novelty, but as a thought experiment.” He stresses questioning status quo, not necessarily to change, but to break mental boundaries and unlock creativity
The Studio at Kendall: Candel and IDEA Pharma CEOs on mindset and communication in biotech innovation
The Studio at Kendall: Candel and IDEA Pharma CEOs on mindset and communication in biotech innovation.
At ASCO 2025, BiotechTV sat down with Paul Peter Tak, MD PhD FMedSci, CEO of Candel Therapeutics, to discuss the firm’s pivotal Phase 3 prostate cancer data and the future outlook for its viral immunotherapy platform.
What is CAN-2409?
CAN‑2409 is an off‑the‑shelf adenovirus-based immunotherapy, a replication-deficient viral vector engineered to deliver cytotoxic gene therapy directly within tumours. Designed to synergize with standard radiotherapy, CAN‑2409 aims to enhance local tumour control and systemic immune activation.
Key Prostate Cancer Data from ASCO
- The Phase 3 trial evaluated CAN‑2409 plus radiotherapy versus radiotherapy alone in localised non-metastatic prostate cancer.
- The primary endpoint, disease-free survival (DFS), showed a 30% reduction in risk of recurrence or death (hazard ratio ≈ 0.70), a statistically significant improvement even in patients with age-related non-cancer deaths factored in.
- Cancer-specific DFS, excluding non-cancer deaths, demonstrated an even stronger benefit (~38% risk reduction).
- Two-year biopsies revealed that over 80% of patients on CAN‑2409 had pathological complete responses, compared to ~64% with radiotherapy alone.
These data mark a milestone in prostate cancer treatment, addressing a critical gap in improving curative outcomes beyond standard modalities.
Development Path & Regulatory Strategy
Tak explained that the Phase 3 study was conducted under an FDA Special Protocol Assessment (SPA), ensuring alignment on design and endpoints with regulatory expectations. Looking ahead, the team is actively preparing for BLA submission and scaling manufacturing to support commercial readiness across indications beyond prostate cancer.
The Bigger Picture: Pipeline Expansion
Beyond prostate cancer, Candel is advancing CAN‑2409 in borderline-resectable pancreatic cancer and therapy-resistant non‑small cell lung cancer, where unmet needs remain significant. Tak underscored the importance of building a pan–solid tumor immunotherapy pipeline, leveraging viral delivery to tackle difficult-to-treat cancers with limited therapeutic options.
