SHR-1701, a Bifunctional Fusion Protein Targeting PD-L1 and TGFβ, for Recurrent or Metastatic Cervical Cancer: A Clinical Expansion Cohort of a Phase I Study

PURPOSE: Patients with recurrent or metastatic cervical cancer have limited treatment options after platinum-containing treatment. We initiated a phase I study to assess SHR-1701, a novel bifunctional fusion protein composed of a mAb against programmed death ligand 1 (PD-L1) fused with the extracellular domain of TGFβ receptor II, in solid tumors (NCT03774979). Here, results from the cervical cancer cohort are presented. PATIENTS AND METHODS: Patients with recurrent or metastatic cervical cancer who progressed during or after platinum-based therapy were enrolled to receive SHR-1701 at 30 mg/kg every 3 weeks. Primary endpoint was objective response rate (ORR) per RECIST v1.1. RESULTS: In total, 32 patients were recruited. ORR was 15.6% 95% confidence interval (CI), 5.3-32.8, and disease control rate was 50.0% (95% CI, 31.9-68.1). Responses were still ongoing in 80.0% of the responders; 6-month duration of response rate was 80.0% (95% CI, 20.4-96.9). Median progression-free survival (PFS) was 2.7 months (95% CI, 1.4-4.1). Of note, as assessed by immune-modified RECIST, median PFS was 4.1 months (95% CI, 1.6-4.3). Overall survival rate at 12 months was 54.6% (95% CI, 31.8-72.7). Treatment-related adverse events of grade 3 or 4 were reported in 11 (34.4%) patients. No treatment-related deaths occurred. No difference in ORR was found between patients with PD-L1 combined positive score ≥1 or <1; patients with high phosphorylated SMAD2 level in immune cells or tumor cells had numerically higher ORR. CONCLUSIONS: SHR-1701 exhibits encouraging antitumor activity and controllable safety in patients with recurrent or metastatic cervical cancer after platinum-based regimens, and therefore might provide another treatment option for this population. See related commentary by Miller and Friedman, p. 5238.