Background: Erdafitinib is an oral selective pan-fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitor approved in the US for treatment of locally advanced or metastatic urothelial carcinoma in adults with susceptible FGFR3 alterations, as determined by FDA-approved companion diagnostic test, who have progressed during or after ≥1 line of prior systemic therapy. Primary analysis results from the RAGNAR study demonstrated tumor agnostic efficacy in patients with advanced solid tumors with predefined FGFR alterations after failure of standard therapies (Pant 2023). Here we report results on patients with non-small-cell lung cancer (NSCLC) in the RAGNAR study. Methods: Patients with advanced or metastatic squamous or non-squamous NSCLC with prespecified FGFR1-4 alterations (mutations/fusions) and with documented disease progression after exhausting standard therapies were included. Patients with other targetable alterations (eg, EGFR, ALK, ROS1) were excluded. Patients received oral erdafitinib until disease progression or intolerable toxicity. The primary end point was objective response rate by independent review committee. Secondary endpoints include duration of response, disease control rate, progression-free survival, overall survival, and safety. Results: At data cutoff (median survival follow-up of 23.7 months), 23 patients with NSCLC received erdafitinib. Median age was 63 years (range 50-79); 22 (96%) had metastases. Patients had a median of 2 prior lines of systemic therapies (range 1-7; 48% had 3+ prior lines); only 2 (9%) patients had responded to their prior line of therapy. Fourteen patients (61%) had squamous and 9 (39%) non-squamous histology; 13 patients (57%) had FGFRfusions and 10 (43%) had FGFR mutations. Three patients had CDKN2Aand 3 patients had PIK3CA co-alterations. Objective response rate by independent review committee was 26% (95% CI 10-48); disease control rate was 74% (95% CI 52-90). Median time to onset of response was 1.5 months. Responses were observed in 21% (3/14) of patients with squamous; 33% (3/9) with non-squamous histology, 29% (2/7) of patients with FGFR2, 25% (4/16) with FGFR3alterations, and in 20% (2/10) of patients with FGFR mutations and 31% (4/13) with fusions. Median duration of response, progression-free survival and overall survival were 4.6 months, 4.1 months, and 10.5 months, respectively. Most common adverse events (AEs) were diarrhea (65%), stomatitis (61%), dry mouth (44%), hyperphosphatemia (65%), dry skin (30%), and fatigue (22%); 6 (26%) had serious AEs; 2 (9%) discontinued erdafitinib due to AEs. No treatment-related deaths were observed. Conclusions: Erdafitinib demonstrated clinically meaningful activity in pre-treated patients with NSCLC and pre-specified FGFR alterations. Safety data were consistent with erdafitinib safety profile. Clinical trial information: NCT04083976.