The Food and Drug Administration (FDA) has approved Imfinzi (durvalumab; AstraZeneca), a programmed death-ligand 1 (PD-L1) blocking antibody, for the first-line treatment of adult patients with extensive-stage small cell lung cancer (SCLC), in combination with etoposide and either carboplatin or cisplatin.
The approval was based on data from the CASPIAN study, an active-controlled, open-label trial that investigated the combination of durvalumab plus chemotherapy vs chemotherapy alone in previously untreated patients with extensive-stage SCLC (median age: 63 years; 70% male). Among the study population, 90% had Stage IV disease and 10% had brain metastasis at baseline. A total of 25% of patients received cisplatin and 74% received carboplatin. In the chemotherapy alone arm, 57% of patients received 6 cycles of chemotherapy, and 8% received prophylactic cranial irradiation. The primary end point was overall survival (OS); additional efficacy measures included investigator-assessed progression free survival (PFS) and objective response rate (ORR).
Results showed a median OS of 13.0 months in the durvalumab plus chemotherapy arm compared with 10.3 months in the chemotherapy alone arm (hazard ratio [HR] 0.73 [95% CI, 0.59-0.91]; P =.0047). In exploratory subgroup analyses of OS based on the platinum chemotherapy received at cycle 1, HR was 0.70 (95% CI, 0.55-0.89) in patients who received carboplatin and 0.88 (95% CI, 0.55-1.41) in those who received cisplatin.
Additionally, median PFS was observed to be 5.1 months (95% CI, 4.7-6.2) in the durvalumab plus chemotherapy arm and 5.4 months (95% CI, 4.8-6.2) in the chemotherapy alone arm (HR 0.78 [95% CI, 0.65-0.94]. Investigator-assessed confirmed ORR was 68% (95% CI, 62%-73%) in the durvalumab plus chemotherapy arm and 58% (95% CI, 52%-63%) in the chemotherapy alone arm.
With regard to safety, the most common adverse reactions reported in study patients included nausea, fatigue/asthenia, and alopecia.
Commenting on the approval, Dave Fredrickson, Executive Vice President, Oncology Business Unit, said: “Imfinzi is the only immunotherapy to show both a significant survival benefit and improved response rate in combination with chemotherapy for these patients, an important step forward in treating this devastating disease.”
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