Pfizer has announced that a phase 3 study evaluating its investigational anti-PD-1 monoclonal antibody sasanlimab in a subset of bladder cancer patients met the primary endpoint of event-free survival.
The phase 3 CREST trial has been assessing the subcutaneously-administered drug in combination with standard-of-care Bacillus Calmette-Guérin (BCG) as an induction therapy, with or without maintenance, in patients with BCG-naïve, high-risk non-muscle invasive bladder cancer (NMIBC).
Results demonstrated a 32% reduction in the risk of disease-related events, including high-grade disease recurrence or progression, with the sasanlimab combination compared to BCG treatment alone.
The probability of being event-free at 36 months was 82.1% with the sasanlimab combination (induction and maintenance), compared to 74.8% with BCG alone (induction and maintenance), Pfizer said.
The company added that sasanlimab plus BCG (induction only) did not extend event-free survival compared to BCG alone (induction and maintenance), a key secondary endpoint in the study, “underscoring the need for BCG maintenance not only as a component of standard-of-care treatment but also in combination with sasanlimab”.
Bladder cancer is the ninth most common cancer globally and NMIBC, in which the cancer cells are confined to the inner lining of the bladder, accounts for approximately 75% of all cases.
Despite treatment with BCG, up to 50% of high-risk NMIBC patients experience disease recurrence and often require a radical cystectomy, which is associated with significant risks.
Megan O’Meara, interim chief development officer, Pfizer Oncology, said the findings from CREST “offer a much-needed therapeutic breakthrough and spotlight sasanlimab as the first immunotherapy combination with BCG to significantly improve outcomes for patients with BCG-naïve, high-risk NMIBC in over three decade”.
Results have now been shared with global health authorities to support potential regulatory filings, the company outlined.
“We look forward to working with global regulatory authorities to potentially bring sasanlimab as an important new treatment option to patients with high-risk NMIBC,” O’Meara said.
The announcement comes just days after Pfizer’s Hympavzi (marstacimab) was approved by the UK Medicines and Healthcare products Regulatory Agency (MHRA) to treat haemophilia A or B in adult and paediatric patients.