Dr Silverstein on the Efficacy of Abemaciclib Plus Hormonal Therapy in Recurrent Low- or High-Grade Serous Ovarian Cancer

“Patients [with low-grade serous ovarian cancer] are really benefiting from this combination. Putting the data into [perspective]…after these patients progress on single-agent hormonal therapy, [their options are limited to] further chemotherapy or MEK inhibitors, which are [both] toxic. We hope these data can support further study [of CDK4/6 inhibition plus hormonal therapy] in [this patient population].”

Jordyn Silverstein, MD, a hematology/oncology fellow at UCLA Health, discusses data from a nonrandomized, open-label, phase 2 study evaluating the efficacy of adding the CDK4/6 inhibitor abemaciclib (Verzenio) to hormonal therapy in patients with recurrent, low- or high-grade serous ovarian cancer or endometroid endometrial cancer.

A total of 41 patients were enrolled to the trial, and 35 were included in the response analysis. Silverstein noted that the group was almost evenly split between those with ovarian cancer (n = 20/41) and those with endometrial cancer (n = 21/41). More patients had low-grade disease vs high-grade disease (n = 12 vs n = 8), and most had advanced stage disease, mostly stage III (n = 15) and stage IV (n = 15).

Data shared during the 2025 SGO Annual Meeting on Women’s Cancers showed that the 24-week progression-free survival (PFS) rate was 72.3% in those with low-grade serous ovarian cancer (LGSOC). Silverstein underscored that the most promising results were reported in those with LGSOC, noting that most patients achieved stable disease. This is a goal from a quality-of-life standpoint, Silverstein said, if patients are able to stay on a treatment for years with minimal toxicity and have stable disease.

Patients with LGSOC who progress after single-agent hormonal therapy can receive chemotherapy or MEK inhibition although both approaches are toxic, Silverstein noted. These findings may support additional study in this patient population.

In those with high-grade serous ovarian cancer and endometrioid endometrial cancer, the 24-week PFS rates were 12.5% and 50.0%. Despite selecting patients hypothesized to be more sensitized based on their molecular features, those with high-grade serous ovarian cancer experienced minimal responses, according to Silverstein. Those with endometrioid endometrial cancer experienced a median PFS of 6.1 months (95% CI, 2.0-12.3), with some patients on treatment for over 1 year, which suggests that this group derives benefit from this approach, Silverstein concluded.