FROM LANCET ONCOLOGY
Sunitinib elicited an “exceptional” treatment response from refractory thymic carcinoma in an open-label phase II clinical trial involving 40 patients, investigators reported online in Lancet Oncology.
The oral tyrosine kinase inhibitor produced a 26% rate of complete or partial response for thymic epithelial tumors overall and a 91% response rate in the subset of patients with thymic carcinoma. That response was rapid and durable with continued administration of the agent. This is particularly important because most of the study participants had failed on two or more previous treatments including platinum-based chemotherapy, and no other standard treatments are available for patients who have this aggressive cancer. “Our trial is the first to show robust and durable clinical activity of a targeted agent in previously treated patients with thymic carcinoma,” said Dr. Anish Thomas of the Thoracic and Gastrointestinal Oncology Branch, National Cancer Institute, Bethesda, Md., and his associates.
The trial, performed at two U.S. cancer centers during an 18-month period, involved 24 patients with thymic carcinoma and 16 with advanced thymoma whose disease had progressed despite at least one line of platinum-based chemotherapy. All the participants were given oral sunitinib once daily in 6-week cycles until further progression or unacceptable adverse events occurred. A total of 21 of the 23 assessable patients with thymic carcinoma (91%) achieved disease control (partial response or stable disease), as did 13 of the 16 patients who had thymoma (81%), and the median duration of response was 16.4 months. Median progression-free survival was 7.2 months for thymic carcinoma and 8.5 months for thymoma, and 1-year estimated survival was 78% and 86%, respectively.
Sunitinib was generally well tolerated, though many patients required dose reductions. “Considering concurrent cardiac risk factors in patients with thymic epithelial tumors – e.g., previous exposure to anthracyclines, radiation, and high rates of subclinical cardiac tumor involvement – careful monitoring of cardiac function is needed,” Dr. Thomas and his associates said (Lancet Oncol. 2015 Jan. 13 [ doi:10.1016/S1470-2045(14)71181-7 ]).
They noted that these exploratory findings should be viewed with caution and must be confirmed in larger cohorts. At least one such trial (NCT01621568) is currently underway.
