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

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.

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.

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.

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.