What POTOMAC Data Mean for Combination Therapy and Patient Selection

In this installment, Mark D. Tyson II, MD, MPH, asks Alexandra Drakaki, MD, to unpack what the POTOMAC (NCT03528694) data show about how quickly high-risk non–muscle invasive bladder cancer (NMIBC) can progress. She explains that the trial combined durvalumab (Imfinzi), a PD-L1 inhibitor, with BCG across both induction and maintenance phases, and describes the resulting reduction in progression risk that the trial demonstrated.

Tyson calls patient selection the crux of the issue: He doesn't dispute the efficacy signal from POTOMAC, but stresses that identifying which patients should actually receive the combination, rather than proceeding straight to cystectomy or BCG alone, is where the clinical judgment comes in. Drakaki responds that although she isn't the one making that first call, these are exactly the cases she discusses closely with her urology colleagues to reach a shared decision.

Tyson then adds a point of clarification for viewers about the POTOMAC trial design: The combination wasn't tested specifically in a post-induction or re-induction setting, which he says is an important distinction. He also highlights that the efficacy signal appeared stronger among patients with papillary disease, including those with concurrent carcinoma in situ (CIS), than among patients with BCG-naive CIS alone. As a POTOMAC investigator himself, he notes the patients he tended to enroll were largely those with T1 disease who could have gone straight to cystectomy but preferred to avoid it, underscoring that the trial population, and the resulting data, may not generalize evenly across every high-risk NMIBC presentation.

Tyson also revisits additional POTOMAC findings that Neal D. Shore, MD, FACS, presented at the 2026 American Urological Association Annual Meeting. He notes these were exploratory end points: time to cystectomy was longer with the durvalumab-BCG combination, at roughly 19 months, compared with about 14 months for BCG alone, and a smaller proportion of patients who progressed on the combination went on to develop BCG-unresponsive disease.

Tyson cautions that these are secondary, exploratory end points drawn from relatively small subgroups within the trial, so he stops short of drawing firm conclusions from them at this stage. He suggests that as longer-term follow-up data mature, these outcomes may offer urologists useful additional context for shared decision-making, but says the current numbers are still too immature to be definitive one way or the other.

In the next episode, "Building the Urologist-Medical Oncologist Care Pathway for NMIBC," the conversation turns to what a strong urology-medical oncology partnership actually looks like in practice, and what each side needs from the other to keep patients on track.