A Phase II Trial of Albumin-Bound Paclitaxel and Gemcitabine in Patients with Newly Diagnosed Stage IV Squamous Cell Lung Cancers

Abstract

Purpose: Gemcitabine and albumin-bound paclitaxel (ABP) exhibit synergistic antitumor efficacy, with ABP serving to increase the intratumoral gemcitabine concentration. Both drugs are active in squamous cell lung cancers (SQCLC) and are conventional partners for carboplatin. We hypothesized that combining gemcitabine and ABP would enhance the antitumor activity in patients with advanced SQCLCs.

Patients and methods: This was a Simon two-stage, open-label, single-arm, multicenter phase II study that enrolled patients between August 1, 2015 and June 1, 2018. We enrolled 37 patients with chemotherapy-naïve, PD-L1 low/unknown advanced stage IV SQCLC. Patients were administered weekly intravenous gemcitabine (1,000 mg/m2) plus ABP (100 mg/m2) in a 3-week on, 1-week off schedule during stage I and a 2-week on, 1-week off schedule in stage II. The primary endpoint was best objective response rate (ORR). Next-generation sequencing by MSK-IMPACT was used to calculate tumor mutation burden and genome doubling and assess somatic variants for correlations with efficacy.

Results: Thirty-two patients were evaluable for response assessment. The study satisfied its primary endpoint, with confirmed partial responses in 18 of 32 patients and a complete response in 1 patient [ORR 59%; 95% confidence interval (CI), 42%-74%]. Median progression-free survival (PFS), a secondary endpoint, was 7.5 (95% CI, 6.7-10.5) months. There were no unexpected toxicities.

Conclusions: Gemcitabine plus ABP was a safe, tolerable, and effective first-line therapy for patients with chemotherapy-naïve SQCLCs, with an ORR and median PFS substantially higher than carboplatin doublet regimens and efficacy comparable with carboplatin plus taxane plus pembrolizumab.

Trial registration: ClinicalTrials.gov NCT02525653.

©2020 American Association for Cancer Research.

Figures

Figure 1.

Waterfall plot of radiographic responses. Light blue indicates patients treated during stage 1. Dark blue indicates patients treated during stage 2. Partial responses were defined as a 30% or larger reduction in tumor size (green line).

Figure 2.

Swimmer plot of responses. Light blue indicates patients treated during stage 1. Dark blue indicates patients treated during stage 2.

Figure 3.

Integrated plot of radiographic response and correlates, including smoking history, PD-L1 tumor proportion score determined via immunohistochemistry (IHC), tumor mutation burden, a consolidated oncoprint of somatic alterations in key PI3K-RTK-RAS members, and genome doubling.