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Adding the investigational multi-kinase inhibitor chiauranib to weekly paclitaxel improves progression-free survival among patients with platinum-resistant or platinum-refractory ovarian cancer, according to findings from the phase 3 CHIPRO trial.

The trial, involving over 400 patients in China, found that chiauranib extended progression-free survival to 4.6 months vs 2.7 months with weekly paclitaxel plus placebo. That translated to a 57% reduction in the risk for progression or death.

Notably, about 10% of patients in the trial had platinum-refractory disease, and roughly 70% had previously received anti-angiogenic therapy.

“CHIPRO is the first randomized study with a substantial primary platinum-refractory population, making it highly relevant to real-world practice,” researcher Xiaohua Wu, MD, of Fudan University Shanghai Cancer Center, Shanghai, China, reported at the American Society of Clinical Oncology (ASCO) 2026 in Chicago.

But while the trial met its primary endpoint, the addition of chiauranib did not lengthen overall survival. Questions were raised about the relatively poor outcomes in the control group.

Tough-to-Treat Population

Chiauranib (also known as ibcasertib) is an oral Aurora B-selective multi-kinase inhibitor designed to target tumor cell proliferation, angiogenesis, and the immunosuppressive tumor microenvironment.

In a phase 2 study, chiauranib in combination with etoposide or weekly paclitaxel showed promising efficacy among patients with platinum-resistant or platinum-refractory ovarian cancer — a population with few effective treatment options and historically poor outcomes.

CHIPRO enrolled 459 patients with platinum-resistant or -refractory ovarian cancer who had received up to five prior lines of therapy. They were randomly assigned 1:1 to chiauranib 50 mg once daily plus weekly paclitaxel or to placebo plus weekly paclitaxel. Paclitaxel was administered on days 1, 8, and 15 of each 21-day cycle for up to six cycles. Patients without disease progression then received maintenance chiauranib or placebo until disease progression, unacceptable toxicity, withdrawal, or death.

Median follow-up was 16.6 months in the chiauranib group and 15.1 months in the placebo group.

The overall response rate was 32% in the combination arm and 14.3% in the placebo group (P < .001). Median duration of response was 5.5 months and 4.1 months, respectively, while tumor reduction occurred in 76.8% and 42.4% of patients.

Wu said the progression-free survival benefit with add-on chiauranib (4.6 months vs 2.7 months) was observed across all predefined subgroups, regardless of prior anti-angiogenic therapy exposure.

Overall survival, however, was not improved, at a median of roughly 12 months in both trial arms — though there were favorable trends in certain subgroups, such as patients previously treated with PARP inhibitors.

As for safety, treatment-emergent adverse events of grade 3 or worse were nearly universal with chiauranib, affecting 90% of patients vs 54% in the placebo group. The most common severe toxicities included neutropenia, leukopenia, and anemia.

Fatal events occurred in seven patients (3.1%) in the chiauranib group and three (1.3%) in the placebo group. Causes of death among patients receiving chiauranib included respiratory failure, infectious pneumonia, gastrointestinal necrosis, biliary tract neoplasm, and circulatory collapse; the investigators considered four of the seven deaths to be possibly treatment-related.

Key Questions Remain

Discussant Katherine Fuh, MD, PhD, of the University of California, San Francisco, described CHIPRO as a “positive” trial that demonstrated a progression-free survival benefit without the need for biomarker selection.

The inclusion of platinum-refractory patients, Fuh said, was a notable feature distinguishing CHIPRO from other recent trials, including KEYNOTE-B96 and MIRASOL.

She pointed out, though, that progression-free survival in CHIPRO’s control arm was lower than outcomes reported for the weekly paclitaxel control arms in other studies. In KEYNOTE-B96, for example, median progression-free survival was just over 7 months with paclitaxel alone.

The relatively poorer outcomes in CHIPRO’s control arm will likely be an important consideration as the data are further evaluated, according to Fuh.

She also noted that CHIPRO enrolled patients exclusively in China and used a modified paclitaxel dosing strategy in which patients started at 60 mg/m² during the first cycle, before escalating to standard dosing in those who tolerated treatment.

Fuh said that additional details regarding dosing intensity and treatment exposure would help contextualize the findings.

Currently, chiauranib is not approved in China or the US. In addition to ovarian cancer, the drug is being studied in small cell lung cancer, pancreatic cancer, sarcoma, and other solid tumors.

The trial was funded by Chipscreen Biosciences, which is developing chiauranib. Wu reported having no disclosures. Fuh reported receiving honoraria from AbbVie, AstraZeneca, and other companies and holding patents for, and receiving royalties from, AVB-S6-500 (batiraxcept).