Outcomes for pembrolizumab stratified by pemetrexed maintenance post pembrolizumab-platinum-pemetrexed induction in metastatic non-small-cell lung cancer.

ABSTRACT

Aim: We assessed treatment patterns and outcomes in patients with metastatic nonsquamous non-small-cell lung cancer (mNSCLC) who initiated first-line pembrolizumab-platinum-pemetrexed (induction) in US community oncology settings. Methods: Patients initiating induction were retrospectively identified. Patients continuing pembrolizumab afterward underwent chart review. Clinical outcomes were described by maintenance pemetrexed exposure after inverse probability of treatment weighting (IPTW). Results: Median induction pembrolizumab and pemetrexed durations were 5.1 and 4.2 months. Among patients continuing pembrolizumab after induction, 64% received maintenance pemetrexed. Common discontinuation reasons for induction pemetrexed were completion of planned therapy (79%) and partial response (68%) and progressive disease (38%) and toxicity (29%) for maintenance pemetrexed. After IPTW, median overall survival and real-world progression-free survival were longer in patients continuing pembrolizumab with versus without maintenance pemetrexed (20.3 vs 12.0 months and 10.3 vs 5.8 months, respectively). Conclusion: Patient characteristics and planned treatment decisions affect maintenance pemetrexed utilization in the community oncology setting.

What is this summary about? Pembrolizumab is a drug that helps the lung cancer patient's immune system fight the cancer, even after the cancer has spread, or metastasized. After the patient gets better, the patient is treated with chemotherapy so the cancer will not come back. This is called 'maintenance treatment'. In KEYNOTE-189, a clinical trial, patients lived longer if they had pembrolizumab added to pemetrexed and platinum, which are chemotherapy drugs. If patients had maintenance treatment with pembrolizumab and pemetrexed, they also lived longer. However, do patients in community practices get those treatments? What were the results? We found that at cancer practices in the community instead of clinical trials, not all patients received pemetrexed in maintenance treatment. Many had finished their planned therapy and their tumors had shrunk. Also, some physicians chose not to give their patients pemetrexed. In addition, some women and some older and sicker patients did not get pemetrexed. Some patients had pemetrexed in maintenance but stopped because their cancer grew worse or because they had side effects. Those patients did not live as long as patients who did have maintenance pemetrexed. What do the results mean? Patients with metastatic non-small-cell lung cancer in the community practice do better on the treatments tested in clinical trials. However, certain patients do not get those treatments. The reasons need to be understood, to make sure that those patients get better treatments.