PD-1 inhibitor combined with albumin paclitaxel and apatinib as second-line treatment for patients with metastatic gastric cancer: a single-center, single-arm, phase II study

Immune checkpoint inhibitors have been approved for first- and third-line treatment of advanced gastric cancer. However, pembrolizumab alone in the second line did not improve overall survival compared to chemotherapy in the KEYNOTE-061 study. In this study, we aimed to explore the efficacy and safety of a three-drug regimen of PD-1 inhibitor combined with albumin paclitaxel and apatinib (a VEGFR inhibitor) for the second-line treatment of patients with metastatic gastric cancer (mGC).

This was a single-center, single-arm, phase II clinical study. Patients with mGC with stable microsatellite and negative HER-2 expression who failed first-line chemotherapy were enrolled. The enrolled patients were treated with PD-1 inhibitor (selected according to patients’ requirements) in combination with albumin paclitaxel (125 mg/m², intravenously, days 1 and 8, or 250 mg/m², intravenously, day 1) and apatinib (250 or 500 mg, orally, days 1–21) every 3 weeks. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were overall survival (OS), objective response rate (ORR), disease control rate (DCR), duration of response, and adverse events (AEs).

From July 11, 2019, to October 13, 2022, a total of 43 patients were enrolled, of whom 10 were PD-L1 negative, 11 were PD-L1 positive, and 22 had unknown PD-L1 expression. As of the data cutoff on April 1st, 2023, nine patients had partial response, 29 had stable disease, and five experienced progressive disease, with the ORR of 20.9% and DCR of 88.3%. The median PFS was 6.2 months (95% CI, 3.9–9.3), and the median OS was 10.1 months (95% CI, 7.5–14.1). All patients suffered from alopecia and neurotoxicity. The other main AEs of grade 1 or 2 were bone marrow suppression (N = 21, 48.8%), hand-foot reaction (N = 19, 44.2%), hypertension (N = 18, 41.9%), hypothyroidism (N = 11, 25.6%), gastrointestinal bleeding (N = 3, 7.0%), and liver function damage (N = 5, 11.6%). Two patients reported grade 3–4 immune-related liver damage.

Second-line PD-1 inhibitor combined with albumin paclitaxel and apatinib showed certain efficacy and safety in patients with mGC.

Clinical trials, NCT04182724. Registered 27 November 2019; retrospectively registered, https://​clinicaltrials.​gov/​study/​NCT04182724