Phase III CHIPRO Trial Shows Progression-Free Survival Benefit in Platinum-Resistant Ovarian Cancer

Platinum-resistant ovarian cancer occurs when tumors stop responding to platinum-based chemotherapy (e.g., cisplatin or carboplatin) or return within six months of treatment completion. It can be challenging to treat this cancer type, leaving many patients with limited treatment options and poor outcomes. Developing new therapies for platinum-resistant ovarian cancer is an important focus in gynecologic oncology care. 

At ASCO’s 2026 Annual Meeting, Xiaohua Wu, MD, presented findings from the phase III CHIPRO study evaluating chiauranib in combination with weekly paclitaxel for platinum-resistant or refractory ovarian cancer. 

The study met its primary endpoint, demonstrating a significant improvement in progression-free survival compared with weekly paclitaxel alone.

Platinum-Resistant Ovarian Cancer Remains Difficult to Treat

Ovarian cancer is often diagnosed in the advanced stages, and many patients eventually experience recurrence after initial treatment. About 20-30 percent of patients develop platinum-resistant disease, including a smaller group with primary platinum-refractory cancer that progresses during or shortly after initial treatment.

Historically, these patients have faced lower response rates and fewer effective non-chemotherapy options than those whose disease remains platinum-sensitive.

Investigators designed the CHIPRO trial to evaluate whether adding chiauranib, a multi-target kinase inhibitor, to weekly paclitaxel could help overcome treatment resistance and improve outcomes.

Trial Demonstrated Significant Progression-Free Survival Improvement

The phase III study enrolled 459 patients with platinum-resistant or platinum-refractory ovarian cancer who had received between one and five prior lines of therapy.

Patients were randomized to receive either:

• Chiauranib plus weekly paclitaxel (CB)
• Placebo plus weekly paclitaxel (PP)

After six cycles, patients continued oral chiauranib or placebo as maintenance therapy.

Here are the key findings:

• Median progression-free survival of 4.57 months in the CB group
• Median progression-free survival of 2.69 months in the PP group
• A 57 percent reduction in the risk of disease progression or death

“Progression-free survival was significantly improved in the CP group compared with the PP group,” Dr. Wu said during the presentation.

He also reported higher response rates among patients receiving the combination therapy.

Overall Survival Benefit Was Not Yet Demonstrated

While progression-free survival improved significantly, Dr. Wu and his team did not observe a statistically significant difference in overall survival across participants.

However, he noted favorable trends in several subgroups, including patients without prior PARP inhibitor exposure and some patients who later received platinum-based chemotherapy.

Additional follow-up may help clarify the treatment’s long-term impact on survival.

The Takeaway

The phase III CHIPRO study demonstrated a significant progression-free survival benefit for patients with platinum-resistant or platinum-refractory ovarian cancer, a population with limited treatment options and historically poor outcomes.

Dr. Wu noted that “CHIPRO is the first randomized study with a substantial primary platinum-refractory population,” potentially making the findings especially relevant to real-world clinical practice.

While additional research is necessary to better understand the therapy’s impact on overall survival, the results suggest that chiauranib plus weekly paclitaxel may offer a new treatment option for patients facing one of the most difficult-to-treat forms of ovarian cancer.

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