SHR-1701 in combination with platinum-based chemotherapy and BP102 (a bevacizumab biosimilar) for persistent, recurrent, or metastatic cervical cancer: Data from a phase 1b/3 study

5529 Background: Platinum-based chemotherapy (chemo) ± bevacizumab is the standard first-line therapy for cervical cancer, regardless of PD-L1 expression. SHR-1701 is a novel bifunctional fusion protein targeting PD-L1 and TGF-βRII, and shows promising efficacy and controllable safety in pretreated patients (pts) with cervical cancer. This ongoing phase 1b/3 study aims to assess the addition of SHR-1701 to standard first-line therapy. Methods: In the phase 1b part, eligible pts had persistent, recurrent, or metastatic squamous-cell carcinoma, adenocarcinoma, or adenosquamous cell carcinoma of the cervix not previously treated with systemic chemo for recurrence or metastasis and not amenable to curative treatment. Prior chemo-radiotherapy was permitted for recurrence, if mono-chemo was used as sensitizer. Pts were given SHR-1701 (30 mg/kg), paclitaxel (175 mg/m 2 ), cisplatin (50 mg/m 2 ) / carboplatin (AUC 5), and BP102 (15 mg/kg) every 3 weeks. The primary endpoints were safety and ORR. Results: From Feb 26 to Aug 12, 2022, 31 pts were enrolled. Median age was 55 years (range, 27-71). 24 (77.4%) had squamous-cell carcinoma, and 7 (22.6%) had adenocarcinoma. 20 (64.5%) had metastatic disease, 7 (22.6%) had recurrent cervical cancer, and 4 (12.9%) had persistent cervical cancer. Grade ≥3 treatment-related adverse events (TRAEs) were reported in 25 (80.6%) pts, with the most common being decreased neutrophil count (n=16, 51.6%), decreased white blood cell count (n=12, 38.7%), and anemia (n=8, 25.8%). TRAEs led to discontinuation of any study agent in 8 (25.8%) pts; of note, only 2 (6.5%) pts discontinued SHR-1701 due to TRAEs (grade 3 infusion reaction and grade 3 immune-mediated rash). No treatment-related deaths occurred. Efficacy outcomes are summarized in Table. ORR was 77.4%, with 4 CRs and 20 PRs; responses were ongoing in all 24 responders. DCR was 93.5%. Shrinkage in target lesions was observed in 30 (96.8%) pts. PFS rate at 6 months reached 93.5%. Conclusions: SHR-1701 plus platinum-based doublet chemo and BP102 provided a manageable safety profile and potent antitumor activity in pts with persistent, recurrent, or metastatic cervical cancer, supporting the subsequent randomized, double-blind, placebo-controlled phase 3 part. Clinical trial information: NCT05179239 . [Table: see text]