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 = 0.03) and progression-free survival (median 7.4 vs. 1.8 months; HR, 0.2; 95% confidence interval, 0.07-0.67; P = 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 = 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.