Background: Plin, is a novel, non-G-CSF, small molecule agent with comparable CIN-preventive effects vs pegfilgrastim. In contrast to pegfilgrastim, Plin is given on the same day of chemo (30 mins after chemo), and does not cause bone pain, nor thrombopenia. In the two randomized controlled (placebo (Plac)/no treatment) cancer trials, Phase (Ph) 2 Study 101 and Ph3 Study 103, single-agent (SA) Plin reduced estimated Doc-induced mean duration of severe neutropenia by > 1 Day vs Plac. We conducted a post hoc analysis of safety, tolerability, and QoL in NSCLC pts from these trials. Methods: NSCLC pts in 2^nd/3^rd line, with at least 1 NCCN FN risk factor, were randomized to Doc (75 mg/m²) + Plin (n = 116; at the CIN dose of 20 mg/m² or its pharmacokinetic equivalent), or Doc + Plac (n = 296) in trials 101 (NCT00630110) and 103 (NCT02504489). Doc was given on day (D) 1, and Plin was given twice per cycle, on D1 and D8 (Plin D1 and D8 dosing is supratherapeutic for CIN but facilitated a more robust safety/tolerability evaluation [the CIN Plin dose is D1 only]). Safety blood draws and AE collection on D1 and D8; tolerability; and QoL (pre-dose and D8) were evaluated over 4 cycles. All pts received dexamethasone premedication. QoL scores were obtained in study 103 only, with Plin (n = 80) and Plac (n = 234), by validated questionnaires (EORTC QLQ C30, to evaluate global health status/QoL; the combined symptom scales/items, and the lung cancer-specific QoL questionnaire QLQ-LC13). Results: QoL scores over 4 cycles between Plin and Plac were similar, indicating Plin was well-tolerated. Grade (Gr) 3/4 AEs of interest for Plin (+Doc) and Plac (+Doc) are summarized in the table. With Plin, AE frequency of diarrhea was slightly higher (5.2% vs 1%; 1 Gr4 case with Plin), but was manageable, and so was hypertension (11.2% vs 1.7%; all Gr3 cases) vs Plac. Hypertension occurred around the time of infusion and was short-lasting (~2-4 hours) and typically self-limiting. Plin had less AEs of neutropenia (16.4% vs 50.3%) and leukopenia (15.5% vs 38.5%) vs Plac. Conclusions: Plin is an effective agent for CIN, has a favorable safety, tolerability, and QoL profile, and has the advantage of dosing on the same day of chemo. Clinical trial information: NCT02504489.