OBJECTIVE: This study is to evaluate the costs, clinical efficacy, and social benefits of a patient assistance program (PAP) implemented by the China Primary Healthcare Foundation for the use of pemetrexed as a first-line non-squamous non-small cell lung cancer (NSCLC) maintenance therapy in China. METHODS: A survival analysis was conducted on the clinical data of 1,366 patients who participated in the PAP. The progression-free survival (PFS) and median maintenance treatment cycle of pemetrexed were analyzed. A 36-month Markov model from a payer's perspective was constructed to analyze the cost and effectiveness associated with the PAP for pemetrexed. The inputs of the model were sourced from the PAP clinical database and published literature. The study estimated the incremental quality adjusted life-years (QALYs) (pemetrexed plus best supportive care [BSC] vs BSC only), the cost saving of the PAP, the impact on the percentage of catastrophic health expenditures (CHE), and poverty headcount ratio (HCR). RESULTS: The median of PFS and maintenance treatment cycles were 187 days and five cycles (total nine cycles, which included four cycles of induction therapy), respectively. The pemetrexed plus BSC treatment with PAP resulted in an additional 0.12 QALYs over BSC only. The total cost was $48,034.46 and $96,191.57 for the patients who had or had not joined the PAP in 3 years, respectively. Compared to the patients without PAP, the percentage of CHE and HCR with PAP was reduced from 98.39% to 19.91% and 66.98% to 4.89%, respectively, indicating that the PAP substantially decreased the number of patients who had CHE and fallen into poverty. CONCLUSION: The study concluded that the pemetrexed PAP generated noticeable clinical and economic benefits to society and to patients. The program also increased patients' compliance with chemotherapy by allowing patients, for whom the pemetrexed treatment was unaffordable, to continue to receive it.