Phase I/II Trial of Exportin 1 Inhibitor Selinexor plus Docetaxel in Previously Treated, Advanced KRAS-Mutant Non–Small Cell Lung Cancer

Purpose: Patients with Kirsten rat sarcoma viral oncogene (KRAS)–mutant non–small cell lung cancer (NSCLC) have limited therapeutic options. Based on the activity of nuclear export inhibition in preclinical models, we evaluated this strategy in previously treated, advanced KRAS-mutant NSCLC. Patients and Methods: The primary outcomes of this multicenter phase I/II dose-escalation trial of selinexor plus docetaxel were safety and tolerability. Selinexor was started 1 week before docetaxel to permit monotherapy pharmacodynamic assessment. Results: Among 40 enrolled patients, the median age was 66 years, 55% were female, and 85% were White. The MTD was selinexor 60 mg orally weekly plus docetaxel 75 mg/m² every 3 weeks. The most common adverse events were nausea (73%, 8% grade ≥3), fatigue (70%, 5% grade ≥3), neutropenia (65%, 60% grade ≥3), and diarrhea (58%, 10% grade ≥3). Of 32 efficacy-evaluable patients, 7 (22%) had partial responses and 18 (56%) had stable disease. Outcomes were not associated with KRAS mutation type but were significantly better in cases with wild-type TP53 (42%), including response and disease control rates (27% and 80% vs. 9% and 27%, respectively; P ¼ 0.03) and progression-free survival (median 7.4 vs. 1.8 months; HR, 0.2; 95% confidence interval, 0.07–0.67; P ¼ 0.003). After selinexor initiation and prior to docetaxel administration, serum lactate dehydrogenase levels increased an average of 51 U/L in TP53-altered cases and decreased an average of 48 U/L in TP53 wild-type cases (P ¼ 0.06). Conclusions: Selinexor plus docetaxel was relatively well tolerated in patients with advanced KRAS-mutant NSCLC. The regimen has promising efficacy in TP53 wild-type cases, in which selinexor monotherapy may also have activity.