Pemetrexed versus docetaxel in second line non-small-cell lung cancer: results and subsets analyses of a multi-center, randomized, exploratory trial in Chinese patients

Background: Pemetrexed and docetaxel are established therapies in second line non-small cell lung cancer (NSCLC). Comparative data, concerning the two agents in the designated settings, however, are lacking in Chinese patients who account for the largest lung cancer population in the world.

Methods and patients: We designed and performed a multi-center, randomized, exploratory clinical trial of pemetrexed compared with docetaxel in second line chemotherapy in Chinese NSCLC patients. Eligible patients with histological or cytological diagnosis of stage IIIB or IV NSCLC, who were not suitable for curative therapy and had failed from prior first line chemotherapy regimen for at least 4 weeks, were randomized to receive either pemetrexed 500 mg/m(2) intravenously day 1 with vitamin B12, folic acid, and dexamethasone, or docetaxel 75 mg/m(2) intravenously day 1 with dexamethasone. Both regimens were implemented once every 21 days for 2 cycles. This study was designed to be a non-inferiority trial that compared tumor response for overall response rate (ORR) between the two drugs as primary endpoint. The secondary endpoints included disease control rate (DCR), Karnofsky performance status (KPS) scores and toxicities.

Results: 260 patients were enrolled and randomly assigned to receive chemotherapy of either pemetrexed (132 patients) or docetaxel (128 patients). 106 patients in pemetrexed arm and 102 patients in docetaxel arm were evaluable for efficacy. The efficacy of pemetrexed was equivalent to that of docetaxel in the second-line treatment for Chinese NSCLC (ORR: pemetrexed vs. docetaxel = 9.4% vs. 4.9, p = 0.285, DCR: pemetrexed vs. docetaxel = 67.2% vs. 69.6%, p = 0.685). And pemetrexed seemed to slightly promote patients' average KPS score when comparing with docetaxel, although the difference was without statistical significance (changes of average KPS scores: pemetrexed vs. docetaxel = 0.28 ± 5.93 vs. -1.67 ± 8.57, p = 0.149). Patients receiving pemetrexed experienced significantly lower incidences of grade 3/4 neutropenia (7.0% vs. 27.6%, p < 0.001) and leucocytopenia (4.7% vs. 22.8%, p < 0.001) than those who received docetaxel. Also, there were lower incidences of alopecia, stomatitis, and neural abnormality for patients receiving pemetrexed than those receiving docetaxel. Incidence of serum glutamic oxaloacetic transaminase elevation, however, was higher in pemetrexed arm than in docetaxel arm (32.3% vs. 14.9%, p = 0.013). In addition, age ≥ 60 patients benefit from pemetrexed with equivalent efficacies yet much lower toxicities compared to docetaxel (DCR: pemetrexed vs. docetaxel = 66.67% vs. 81.58%, p = 0.146; grade 3/4 hematologic toxicities: pemetrexed vs. docetaxel = 17.25% vs. 39.6%, p = 0.016).

Conclusion: Treatment with pemetrexed resulted in equivalent efficacy outcomes and better safety profiles compared with docetaxel in second-line therapy for advanced NSCLC in Chinese lung cancer population. And age ≥ 60 patients may benefit from second-line single pemetrexed.