Background: Pemetrexed maintenance therapy is associated with superior survival in stage IV nsqNSCLC patients. We have observed long term disease control in some patients treated with at least one cycle of Pem/Plat with potential for maintenance pem. There are no reports of data regarding long term PFS and OS in patients treated with Pem regimens. The objectives of our retrospective analysis are to determine the frequency of long term disease control on Pem maintenance and to identify parameters associated with longer PFS/OS. Methods: We included all patients with Stage IV nsqNSCLC who received at least one cycle of pem/plat between May 2010 and Nov 2013. We identified 240 patients from our database and analyzed their demographics, lab values, dates of therapy, and dates of progression. PFS/OS was estimated by the Kaplan-Meier method and associations with patient characteristics were assessed by log-rank tests and Cox proportional hazards analysis. The shortest potential follow up was 5 years. Results: Median age was 66 years, 60% were female, and 72% were Caucasian. Baseline ECOG performance status was 0(22%), 1(50%) and ≥ 2(22%). Median PFS was 6.2 months. At 1, 2, 3, 4, and 5 years of follow up absence of disease progression was seen in 33%, 14%, 7.5%, 4%, and 3%, respectively. Additionally, in terms of OS at 1-5 years, we observed 54.5%, 35%, 21%, 14%, and 11%. Lower baseline neutrophil: lymphocyte ratio (NLR) was strongly associated with improved PFS when using NLR≤5 vs > 5 (median PFS 13.2 mo vs 5.6 mo) Additionally, baseline Hemoglobin (mean = 12.03 g/dL, HR = .904, p = .0046) and Albumin (mean 3.3 g/dL, HR = .7722, p = .024) were associated with better PFS. Conclusions: The similarity in median PFS in our patients (6.2 mo) and clinical trial data suggests that our group of real world patients did not have uniquely favorable baseline characteristics. However, the patients most likely to reach long PFS/OS milestones had favorable baseline prognostic indicators suggesting that this patient subset might also be most likely to benefit from the recently approved regimen which combined Pembrolizumab with Pemetrexed/Carboplatin.