Pfizer’s Sasanlimab in Combo with Standard of Care Improves Event-Free Survival in High-Risk Bladder Cancer

Pfizer announced promising results from its Phase III trial investigating the efficacy of sasanlimab, an anti-PD-1 monoclonal antibody, in combination with standard of care Bacillus Calmette-Guerin (BCG) immunotherapy for patients with high-risk non-muscle invasive bladder cancer (NMIBC) who are BCG-naïve.

The Phase III CREST trial met its primary endpoint, demonstrating that as a first-line treatment, the combination significantly improved event-free survival (EFS) compared to BCG monotherapy.

NMIBC accounts for approximately 70-80% of all newly diagnosed bladder cancer cases. Among these, high-risk NMIBC presents a significant clinical challenge due to its high recurrence and progression rates.

According to Pfizer, approximately 100,000 people globally are diagnosed with high-risk NMIBC.

Induction therapy with BCG has been the standard of care for high-risk NMIBC for decades, but the need for improved outcomes remains. Moreover, 40-50% of patients experience recurrent disease requiring the need for cystectomy, which is associated with significant risks and bladder-sparing treatment options remain limited.

Sasanlimab, a subcutaneous anti-PD-1 therapy, offers a novel immunotherapy approach that enhances the anti-tumor immune response.

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Pfizer hasn’t shared the exact data from the Phase III trial yet in terms of the numbers, but it said it will be sharing them at an upcoming congress.

All of the patients in the trial, in both cohorts, went on to receive BCG as a maintenance therapy. A third group did not undergo a maintenance period and was used in secondary endpoints.

All patients in the two arms included in the primary analysis later received BCG as a maintenance therapy.

“The initial therapy of high-risk, non-muscle invasive bladder cancer with BCG has not advanced in decades. Today’s pivotal Phase III CREST results are potentially practice-changing, representing the first advance in therapy for BCG-naïve, high-risk, non-muscle invasive cancer in over 30 years,” commented Dr. Roger Dansey, chief oncology officerat Pfizer.

One of the secondary measures includes evaluating sasanlimab without BCG maintenance, as reducing BCG use would be beneficial given the long-standing, global BCG shortage.

Merck is the only maker and supplier of BCG to the US. The worldwide shortage began in 2019 and is expected to continue for years.

Last year, Merck said due to increasing global demand for TICE BCG, the company could not keep up with manufacturing enough of it.

To address the shortage, in 2020, the maker committed to expanding its manufacturing capacity for TICE BCG through construction of a new manufacturing facility in Durham, North Carolina.

Merck makes TICE BCG at just one plant in the US for distribution in 70 countries worldwide.

Also last year, the FDA shared a presentation addressing the shortage, which included limited use of BCG in certain indications such as low-risk disease, lowering its dosage and reducing the maintenance period of use.

Pfizer said it plans to discuss the data with global health authorities to support potential regulatory filings.

If approved, it would become the first PD-1 drug approved in the indication.

Pfizer believes sasanlimab holds a distinct advantage even if future competitors emerge, thanks to its simpler, lower-volume subcutaneous injection compared to other checkpoint inhibitors.

The pharma giant also said it is continuing to investigate sasanlimab in combination with the company’s antibody drug conjugate (ADC) portfolio in advanced solid tumors.

Having its own checkpoint inhibitor to combine with its ADCs rather than from other companies would make things easier to coordinate in clinical trials.

During Pfizer’s oncology innovation day last year, Dansey even described sasanlimab as a “golden egg” to highlight the antibody’s exceptional potential and versatility. “It’s well-configured, a true PD-1 inhibitor and an ideal partner for antibody-drug conjugates (ADCs),” he said.

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