Avelumab combined with axitinib for patients with advanced thymoma B3 and thymic carcinoma

Introduction: Patients with advanced thymoma B3 (TB3) and thymic carcinoma (TC) resistant to chemotherapy have limited treatment options. The final overall survival (OS) results of the CAVEATT trial are presented. Methods: The CAVEATT was a single-arm, multicentric, phase II trial testing the combination of avelumab (anti–PD-L1) and axitinib (antiangiogenesis) in patients with advanced TB3 or TC, who had progressed after at least one line of platinum-based chemotherapy. Patients could have received prior antiangiogenesis drugs but not immune checkpoint inhibitors. Results: Thirty-two patients were enrolled: 27 had TC, 3 TB3, and 2 a mixed TB3/TC. Most (91%, 29/32) had Stage IVB disease, and 41% (13/32) had prior antiangiogenesis treatment. After a median follow-up for overall survival (OS) of 48.9 months (range, 2.5–61.1), 23 deaths occurred. Median OS was 23.4 months (95% CI, 16.5–31.1), with 12- and 24-month OS rates of 77.7% (95% CI, 58.8–88.7) and 48.5% (95% CI, 30.3–64.6), respectively. No significant OS differences emerged across most subgroups, except for patients without liver metastases (OS hazard ratio [OS-HR], 0.39; 95% CI, 0.17–0.89) and lower lactate dehydrogenase levels (OS-HR, 0.25; 95% CI, 0.10–0.65), who had significantly longer survival compared to patients with liver metastases and with higher lactate dehydrogenase levels, respectively. Conclusions: The combination of avelumab and axitinib demonstrated long-term efficacy in heavily pretreated patients with TC and TB3. This finding underscores the meaningful impact of immune checkpoint inhibitors and antiangiogenesis drugs on the prognosis of this patient population.