Enfortumab Vedotin & Pembrolizumab Improve Bladder Cancer Outcomes | NEJM Study

For patients with muscle-invasive bladder cancer who are ineligible for cisplatin-based chemotherapy, a combination of perioperative enfortumab vedotin and pembrolizumab, alongside surgery, demonstrates significantly improved outcomes compared to surgery alone. Findings from a recent study published in the New England Journal of Medicine reveal substantial benefits in event-free and overall survival.

A New Option for Cisplatin-Ineligible Patients

The research, led by Christof Vulsteke, M.D., Ph.D., from Antwerp University in Belgium, focused on a population often excluded from standard treatment protocols. Cisplatin, a common chemotherapy drug, is highly effective against bladder cancer but carries significant side effects, making it unsuitable for many patients. This study addressed a critical demand for alternative, effective therapies for this group.

The trial involved 344 participants diagnosed with muscle-invasive bladder cancer who were candidates for radical cystectomy (surgical removal of the bladder) with pelvic lymph node dissection, but were either unable or unwilling to undergo cisplatin-based chemotherapy. Participants were randomly assigned to receive treatment with both enfortumab vedotin and pembrolizumab before and after surgery, or to undergo surgery alone.

Significant Improvements in Survival Rates

The results showed a marked difference in event-free survival (EFS) – the time until the cancer returns or a patient dies from any cause. At two years, 74.7% of patients in the enfortumab vedotin-pembrolizumab group remained event-free, compared to just 39.4% in the surgery-alone group. This translates to a hazard ratio of 0.40, indicating a substantial reduction in the risk of an event. Overall survival also showed a significant improvement, with estimated rates of 79.7% and 63.1% respectively, and a hazard ratio for death of 0.50.

Beyond survival, the study also examined pathological complete response – the absence of any detectable cancer cells after surgery. A remarkable 57.1% of patients in the combination therapy group achieved a complete response, compared to only 8.6% in the control group. This suggests the treatment effectively shrinks or eliminates the tumor before surgical removal.

Understanding the Treatment Combination

Enfortumab vedotin and pembrolizumab are both targeted therapies that work by harnessing the body’s immune system to fight cancer. Pembrolizumab is an immunotherapy drug that blocks the PD-1 protein, allowing the immune system to recognize and attack cancer cells. Enfortumab vedotin, is an antibody-drug conjugate that delivers a potent chemotherapy drug directly to cancer cells expressing a specific protein. Combining these two therapies appears to create a synergistic effect, enhancing the immune response and maximizing cancer cell destruction.

Adverse Events and Considerations

As with any cancer treatment, the combination therapy was associated with adverse events. All participants in the enfortumab vedotin-pembrolizumab group experienced at least one adverse event, with 71.3% reporting grade 3 or higher events (serious side effects). Drug-related adverse events of grade 3 or higher occurred in 45.5% of this group. Though, the control group also experienced significant adverse events, with 64.8% reporting grade 3 or higher events and 45.9% experiencing drug-related events of the same severity. These findings highlight the importance of careful monitoring and management of side effects during treatment.

FDA Approval and Implications for Clinical Practice

Based on the compelling results of this trial, the Food and Drug Administration (FDA) approved neoadjuvant (before surgery) followed by adjuvant (after surgery) enfortumab vedotin plus pembrolizumab for adults with muscle-invasive bladder cancer who are ineligible for cisplatin. The FDA’s approval marks a significant advancement in the treatment of this aggressive cancer, offering a new hope for patients who previously had limited options. The recommended dose of pembrolizumab for this neoadjuvant treatment is 200 mg administered intravenously every three weeks in combination with enfortumab vedotin-ejfv.

Study Limitations and Future Research

Although the study results are promising, it’s key to acknowledge certain limitations. The trial was conducted at multiple centers and included a specific population of patients ineligible for cisplatin. The findings may not be generalizable to all patients with muscle-invasive bladder cancer. Further research is needed to determine the efficacy and safety of this combination therapy in other patient populations, including those who are eligible for cisplatin but may prefer to avoid its side effects. Long-term follow-up is crucial to assess the durability of the observed benefits and identify any potential late-onset adverse effects.

Ongoing research, such as the phase III EV-302/KEYNOTE-A39 trial evaluating enfortumab vedotin plus pembrolizumab in a broader population of patients with advanced urothelial cancer, continues to build on these findings. This trial aims to further refine our understanding of the role of this combination therapy in the treatment of bladder cancer.

What Comes Next: Monitoring and Guidance Updates

The approval of this new treatment regimen will likely prompt updates to clinical practice guidelines for muscle-invasive bladder cancer. Oncologists will need to carefully consider the benefits and risks of this combination therapy when making treatment decisions for their patients. Continued surveillance of treatment outcomes and adverse events will be essential to ensure the safe and effective implementation of this new approach. The FDA and other regulatory agencies will continue to monitor the safety and efficacy of enfortumab vedotin and pembrolizumab as more data become available.