Qilu Pharmaceutical's QLS5132 Shines at AACR 2026 with Promising Efficacy and Safety Profile in Platinum-Resistant Ovarian Cancer

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On the afternoon of April 19 (U.S. local time), the latest clinical study data on Qilu Pharmaceutical’s innovative drug QLS5132 were presented as an oral report at the 2026 Annual Meeting of the American Association for Cancer Research (AACR).

QLS5132 for Injection is an antibody-drug conjugate (ADC) targeting CLDN6, combining the potent cytotoxic effects of traditional small-molecule drugs with the precise targeting capability of antibody therapeutics. At the 2025 AACR Annual Meeting, preclinical data on QLS5132 were presented in poster format, demonstrating that QLS5132 significantly inhibited tumor growth.

At this year’s AACR Annual Meeting, Professor Zhu Tao from Zhejiang Cancer Hospital delivered an oral presentation in the plenary session on clinical research titled “Therapeutic Advances in ADCs,” presenting the results of the Phase I clinical trial evaluating QLS5132 for the treatment of patients with advanced platinum-resistant ovarian cancer.

Clinical study data show that, as of January 21, 2026, a total of 28 patients with advanced platinum-resistant ovarian cancer were enrolled, including 26 cases of ovarian cancer and 2 cases of fallopian tube cancer. Twenty-three patients had an ECOG performance status score of 1.

In terms of efficacy, the objective response rate (ORR) and disease control rate (DCR) were 50.0% and 94.4%, respectively, with nine subjects achieving partial response (PR). Antitumor activity was particularly pronounced at the 4.8 mg/kg dose level, where the ORR and DCR were 55.6% and 100%, respectively.

Notably, among the 9 subjects who achieved a partial response (PR), 5 maintained their response for more than 3 months. In the 3.2 mg/kg dose group, all patients who achieved PR sustained their response for more than 6 months. Two subjects with undetectable CLDN6 expression achieved PR after treatment, providing promising directions for exploring the drug’s application in a broader population.

In terms of safety, one dose-limiting toxicity (DLT) occurred at the 6.4 mg/kg dose level. At the potential recommended phase 2 dose (RP2D) levels (4.8 mg/kg and 5.6 mg/kg), the most common treatment-related adverse events (TRAEs) with an incidence ≥30% were gastrointestinal and hematologic toxicities, predominantly Grade 1/2, with no Grade 4/5 events reported. No cases of interstitial lung disease, ocular toxicity, or febrile neutropenia occurred. No TRAEs led to treatment discontinuation or death.

In summary, QLS5132 demonstrated a favorable safety profile, particularly at the potential recommended Phase 2 doses (RP2D) of 4.8 mg/kg and 5.6 mg/kg, with a wider therapeutic window and significant antitumor activity in patients with advanced platinum-resistant ovarian cancer. QLS5132 holds promise as a novel treatment option for patients with advanced platinum-resistant ovarian cancer.