An open, prospective, single arm, phase II study of cadonilimab (PD-1/CTLA-4 bispecific antibody) with neoadjuvant chemotherapy in patients with advanced ovarian cancer: Interim analysis from the AK104-IIT-003 study.

Abstract

e17552 Background: There is an unmet need to improve neoadjuvant chemotherapy (NAC) to decrease postoperative residual disease (R0 rate: 50%) and improve prognosis in ovarian cancer (OC). R0 rate and histopathological response of interval cytoreductive surgery (IDS) after NAC combined with immune checkpoint blockades were reported to be encouraging. Cadonilimab (AK104) is a tetravalent bispecific antibody targeting PD-1 and CTLA-4. In this study, we report the efficacy and safety of AK104 with NAC in patients with advanced-stage ovarian cancer (NCT05430906). Methods: This study is an open-label, prospective, single arm, phase II study of evaluating the efficacy and safety of cadonilimab combined with chemotherapy as neoadjuvant treatment for advanced ovarian cancer. Patients received neoadjuvant therapy of cadonilimab plus platinum-taxane chemotherapy (3 to 4 cycles) followed by surgery. Surgery would be performed within 30 days of completion of neoadjuvant therapy. The primary endpoint was the R0 rate. The secondary endpoints included objective response rate (ORR), disease control rate (DCR), chemotherapy response score (CRS), pathologic complete response(pCR), progression-free survival (PFS), and safety. A sample size of 35 achieves 80% power to detect a difference of 0.2 using a two-sided Z-test to estimate the standard deviation with a significance level (alpha) of 0.1. And the sample size was expected to be 40 cases to ensure that the FAS set contains 35 cases for analysis. Results: 17 patients were enrolled from Dec 12, 2022, to Dec 6, 2023. The median patient age was 57 years (range 45–70 years), and most patients presented with high-grade serous carcinoma (94.1%) and stage IVa (5.9%), IVb disease (76.5%). 15 (88.2%) patients had undergone IDS, with an R0 resection rate of 66.7%. ORR was 94.1%, with 1patient achieved CR and 15 patients achieved PR. 11.8% achieved pathological complete response, and 17.6% had a chemotherapy response score (CRS) of 3. PFS or OS data are not mature by cut-off date. Safety and adverse event (AE) were analyzed after completion of neoadjuvant therapy. Treatment-related AEs (TRAEs) of any grade were evaluated for all study populations. TRAEs of any grade occurred in 13 (76.5%) patients. Grade ≥3 TRAEs occurred in 3 (17.6%) patients. The most common TRAEs were thyroid dysfunction (23.5%) and bone marrow suppression (17.6%). Grade ≥ 3 irAE (immune⁃mediated colitis) occurred in 1 (5.9%) patient. All of the TRAEs, including severe AEs, were manageable, with no new safety concerns in this study. Conclusions: This study showed promising activity with a durable clinical response, supporting the potential of NAC with bispecific antibody AK104 in advanced-stage ovarian cancer. Meanwhile, long-term efficacy evaluation still needs following up. Clinical trial information: NCT05430906 .