Combo Therapy Extends Survival in Recurrent Ovarian Cancer Patients

South Korean researchers have developed a method to improve survival rates for ovarian cancer patients who relapsed after targeted therapy treatment.

Yonsei Cancer Center announced on the 27th that a joint research team led by Professor Lee Jung-yoon of the Gynecologic Cancer Center and Professor Cho Hyun-woong of Asan Medical Center's Department of Obstetrics and Gynecology confirmed that combining bevacizumab, an anti-angiogenic targeted therapy, with existing medications in platinum-sensitive ovarian cancer patients who relapsed after PARP inhibitor treatment suppressed cancer progression and could lead to increased patient survival rates.

PARP inhibitors are targeted anticancer drugs that block the repair of DNA, which leads to cancer cell growth. Currently, drugs such as Lynparza (olaparib) and Zejula (niraparib) have been developed and are actively prescribed for ovarian cancer. The problem is that many patients develop resistance during treatment, ultimately leading to cancer recurrence. New strategies were desperately needed as response rates to subsequent treatments are low when cancer recurs after PARP inhibitor therapy.

Recently, combination therapy with bevacizumab, which inhibits new blood vessel formation while inducing hypoxic conditions in cancer cells, has gained attention. When bevacizumab creates hypoxic conditions in cancer cells, DNA repair function weakens, enhancing the effectiveness of PARP inhibitors that block DNA repair. The two drugs work complementarily to create synergy in boosting anticancer effects.

The research team administered niraparib and bevacizumab combination therapy to 44 ovarian cancer patients who relapsed after PARP inhibitor use and observed treatment responses. Approximately 30 patients (68%) achieved six-month progression-free survival, meaning cancer cells did not grow further for six months after treatment.

More than half of patients showed a median progression-free survival of 11.5 months—an improvement compared to approximately four months when only PARP inhibitors were re-administered.

Treatment effects were particularly pronounced in patients who showed complete response (CR) in their previous chemotherapy or maintained long-term response to platinum-based chemotherapy.

Severe adverse reactions of grade 3 or higher occurred in 27.3% of cases, mostly manageable through dose adjustments. No new safety concerns emerged.

While the potential for PARP inhibitor and bevacizumab combination effects had been previously suggested, studies proving clinical efficacy in patients who relapsed after PARP inhibitor treatment were rare.

"This study presents a new maintenance therapy option for patients who relapsed after PARP inhibitor treatment," Professor Lee said. "We confirmed evidence that the combination strategy has high clinical value in patient groups that responded well to platinum-based chemotherapy."

"This result clinically reconfirms treatment strategies targeting cancer's DNA repair mechanisms," Professor Cho said. "This study demonstrates the importance of precision treatment approaches based on patient characteristics."

This phase 2 clinical study was led by the Korean Gynecologic Oncology Group (KGOG) with participation from major domestic institutions including Samsung Medical Center and the National Cancer Center. The findings were published in the latest issue of the international journal Clinical Cancer Research.