What question did this study set out to answer?

This study aims to evaluate the safety and effectiveness of ZW191 in patients with advanced solid tumors.

April 19, 2026

Abstract CT306: Phase 1 first-in-human multicenter open-label study of ZW191, a folate receptor α (FRα)-targeting antibody-drug conjugate (ADC), in patients with advanced solid tumors: Part 1 dose-escalation results

Key Points

This study aims to evaluate the safety and effectiveness of ZW191 in patients with advanced solid tumors.
Multicenter, open-label phase 1 trial focusing on dose escalation.
Participants included adults with recurrent platinum-resistant ovarian, endometrial, and lung cancer.
ZW191 administered intravenously every 3 weeks at varying doses.
Endpoints included safety, tolerability, and tumor response measured by RECIST v1.1.
The study enrolled 51 patients, with a median age of 60 years.
The unconfirmed objective response rate was 52% among evaluable patients.
Notable responses were observed regardless of FRα expression levels.
The most common serious side effects included neutropenia (18%) and anemia (10%).
Patients receiving doses of 6.4 and 9.6 mg/kg had promising response rates.

Abstract

Abstract Background: ZWI-ZW191-101 (NCT06555744) is an ongoing, 2-part study; Part 1 being dose-escalation and Part 2 dose optimization and expansion. Here, we summarize results from Part 1 dose-escalation of the study (data cut: 1 Dec 2025). Methods: Eligible patients aged ≥18 years with recurrent platinum-resistant ovarian cancer (PROC), endometrial cancer (EC), or non-small cell lung cancer (NSCLC) who had progressed on available systemic treatment options, were recruited, independent of FRα expression. Intravenous ZW191 was administered every 3 weeks (Q3W). Part 1 endpoints included safety, tolerability, and antitumor activity per RECIST v1. 1. Results: A total of 51 patients (49 female; median age: 60 years range, 35-79; 35 with OC; 11 with EC; 5 with NSCLC) received ZW191 Q3W (1. 6 mg/kg to 11. 2 mg/kg). Patients had received a median of 3 (1-9) prior lines of treatment. 34 (67%) patients remained on the study treatment at time of data cut. All 51 patients were safety evaluable (Table). The most common Grade ≥3 treatment-related adverse events were neutropenia (18%), anemia (10%), and thrombocytopenia (6%). Among 48 response-evaluable patients (≥1 post-baseline scan), the unconfirmed objective response rate (ORR) was 52% (Table). Responses were observed in tumors with FRα low/negative, intermediate, and high expression. Across doses 6. 4-9. 6 mg/kg, patients with OC and EC had an unconfirmed ORR of 61% and 57%, respectively. Median time to response was 6 weeks. Additional data, including confirmed ORR, duration of response, and progression-free survival, will be presented. Conclusion: ZW191 demonstrated compelling efficacy regardless of FRα expression in a heavily pretreated population of patients with OC and EC, and a favorable safety profile. Dose levels of 6. 4 and 9. 6 mg/kg Q3W are being evaluated in the Part 2a dose optimization phase of the study. Citation Format: Patricia LoRusso, David Sommerhalder, Kosei Hasegawa, Kenichi Harano, David S. Tan, Noboru Yamamoto, David M. O’Malley, Kathleen N. Moore, Sarah E. Church, Lin Lu, Sabeen Mekan, Pranshul Chauha, Jung-Yun Lee. Phase 1 first-in-human multicenter open-label study of ZW191, a folate receptor α (FRα) -targeting antibody-drug conjugate (ADC), in patients with advanced solid tumors: Part 1 dose-escalation results abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts) ; 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86 (8Suppl): Abstract nr CT306.

KI fragen

Bookmark