First-line crizotinib in ALK-positive lung cancer.

To the Editor: Solomon and colleagues (Dec. 4 issue)1 suggest that, as compared with platinum– pemetrexed chemotherapy, crizotinib treatment was associated with significantly longer progression-free survival and an improved objective response rate. However, the interpretation of these results needs some consideration. In the study, platinum–pemetrexed chemotherapy was used every 3 weeks for up to six cycles. However, pemetrexed was not continued beyond the planned six cycles of the combination chemotherapy. The phase 3 PARAMOUNT trial2 suggested that maintenance therapy with pemetrexed after four cycles of combined cisplatin–pemetrexed therapy resulted in a significant reduction of 22% in the risk of death and in an improvement of almost 3 months in median overall survival. Also, in the PARAMOUNT study,3 maintenance therapy with pemetrexed was associated with improved progression-free survival among patients without disease progression after four cycles. The fact that pemetrexed was not continued beyond the planned chemotherapy may have influenced the outcome of the study by Solomon et al. Deniz Tural, M.D.