Clinical Outcomes of the HIV Protease Inhibitor Nelfinavir With Concurrent Chemoradiotherapy for Unresectable Stage IIIA/IIIB Non-Small Cell Lung Cancer: A Phase 1/2 Trial

IMPORTANCE:

Local failure after chemoradiotherapy (CT-RT) significantly contributes to mortality in patients with locally advanced non-small cell lung cancer (LA-NSCLC). One approach to improve local control is through targeted radiosensitization of the tumor.

OBJECTIVE:

To evaluate the dose-limiting toxic effects, maximally tolerated dose, and recommended phase 2 dose of the proteaseinhibitor nelfinavir mesylate, administered concurrently with CT-RT in patients with LA-NSCLC, and, in the phase 2 portion of the study, to estimate the objective response rate, local and distant failure rates, and overall survival.

DESIGN, SETTING, AND PARTICIPANTS:

This prospective, open-label, single-group, single-institution phase 1/2 trial tested the oral protease inhibitor nelfinavir in combination with concurrent CT-RT in 35 patients aged 18 to 89 years with biopsy-confirmed unresectablestage IIIA/IIIB LA-NSCLC and a minimum Karnofsky performance status from June 29, 2007, to February 22, 2012, with an analysis date of May 9, 2017. Median follow-up for all patients was 6.8 years, with a minimum 5 years of follow-up for all survivors.

INTERVENTIONS:

Oral nelfinavir mesylate, 625 mg, twice daily or 1250 mg, twice daily was administered for 7 to 14 days before and during concurrent CT-RT.

MAIN OUTCOMES AND MEASURES:

Graded toxic effects, overall survival, local failure, distant failure, objective response rate, and progression-free survival as measured by Response Evaluation Criteria in Solid Tumors, version 1.1.

RESULTS:

Thirty-five patients (16 women and 19 men; median age, 60 years [range, 39-79 years]) enrolled and met protocol-specified criteria for adherence, with 5 at a dose of 625 mg twice daily and 30 at a dose of 1250 mg twice daily. No dose-limiting toxic effects were observed. No grade 4 or higher nonhematologic toxic effects were observed. Thirty-three of the 35 patients had evaluable posttreatment computed tomographic scans, with an objective response rate of 94% (31 of 33; 95% CI, 86%-100%). The cumulative incidence of local failure was 39% (95% CI, 30.5%-47.5%). Median progression-free survival was 11.7 months (95% CI, 6.2-17.1 months). Median overall survival for all patients was 41.1 months (95% CI, 19.0-63.1 months); the 5-year mean (SE) overall survival rate was 37.1% (8.2%).

CONCLUSIONS AND RELEVANCE:

This study suggests that nelfinavir administered with concurrent CT-RT is associated with acceptable toxic effects and a promising objective response rate, local failure, progression-free survival, and overall survival in unresectable LA-NSCLC. These data suggest that nelfinavir may enhance the efficacy of standard CT-RT in this disease. Additional testing in the randomized phase 3 setting should be conducted to establish the improvement associated with nelfinavir with concurrent CT-RT.