Patients with relapsed or chemotherapy-refractory SCLC have a dismal prognosis. Unfortunately, available treatments result in few durable responses. Pemetrexed is a well-tolerated agent, which is active in NSCLC. Since chemotherapy agents, which are active in NSCLC, are usually also active in SCLC, this trial will examine the efficacy and activity of pemetrexed in this palliative setting