Keytruda Combo Therapy Demonstrates Clinical Benefit and Durable Treatment Response in Recurrent Ovarian Cancer

Treatment with Keytruda (pembrolizumab), Avastin (bevacizumab) and cyclophosphamide in patients with recurrent ovarian cancer was well tolerated and demonstrated clinical benefit in most patients, according to results from a trial published in JAMA Oncology.

“The quality of life of our patients who took part in this clinical trial was excellent,” said Dr. Emese Zsiros, staff physician and faculty member in the department of gynecologic oncology and the Center for Immunotherapy at Roswell Park Comprehensive Cancer Center in Buffalo, New York, said in a press release from her institution. “Most of them were able to travel, spend good time with their families and resume their hobbies — cooking, hiking, things that they were not doing before. And approximately 30% of our patients were still living more than a year and a half after going on this combination, which we did not anticipate. These are very striking results.”

In this phase 2 clinical trial, 40 women (mean age, 62.2 years) with recurrent ovarian cancer were treated with an intravenous infusion of 200 mg of Keytruda and 15 mg/kg of Avastin every three weeks, in addition to 50 mg of oral cyclophosphamide once per day during a treatment cycle lasting 21 days. Women included in this trial also had Eastern Cooperative Oncology Group performance status (a measurement of a patient’s function, with lower scores indicating more functionality) of 0 to 1 and measurable disease according to immune-related Response Evaluation Criteria in Solid Tumors (an evaluation of efficacy and activity of new cancer treatments).

The primary outcomes for this trial was objective response rate (ORR) and progression-free survival (PFS), defined as the time from the initiation of treatment until death, disease progression or last disease assessment. Other secondary end points included severity and frequency of adverse events and duration of response.

Of the patients in this trial, 75% had platinum-resistant disease, defined as recurrence within six months after undergoing most recent platinum therapy, and 25% had platinum-sensitive disease, defined as recurrence at six months or longer after exposure. Platinum compounds refer to treatment with intravenous drugs such as carboplatin and cisplatin.

Complete responses were observed in 7.5% of women, whereas partial responses occurred in 40% of women, and 47.5% had stable disease as a response to the treatment. In addition, the ORR was 47.5%, with 95% obtaining clinical benefit from the treatment and 25% experiencing a durable response. The median PFS throughout the trial was 10 months.

Most common grade 3 to 4 adverse events related to the treatment regimen were lymphopenia (low number of lymphocytes, a type of white blood cell), which occurred in 7.5% of patients, and hypertension (high blood pressure), which was observed in 15% of patients. The adverse events that were most frequently reported throughout the trial include diarrhea (32.5%), fatigue (45%) and hypertension (27.5%).

“There is an unmet clinical need to identify new strategies to improve (immune checkpoint inhibition) efficacy and durability, not only to achieve improved overall survival but also to buy meaningful time with good quality of life for patients with ovarian cancer,” the study authors wrote. “This study’s findings suggest that the combination of (Keytruda) with (Avastin) and oral metronomic cyclophosphamide was safe and well tolerated in patients with recurrent ovarian cancer and may present a promising treatment option.”

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.