The results of a new study show that a bispecific antibody drug, Ubamatamab, has shown good results in ovarian cancer patients and has a good safety profile.
Recently, data from a phase 1 trial showed promising efficacy and a favorable safety profile for ubamatamab monotherapy in heavily pretreated patients with ovarian cancer.
The findings were presented at the 2022 European Society of Medical Oncology Annual Meeting.
Results of the study showed that of the 42 patients who received at least one dose of 20mg or higher of ubamatamab, 14.3% had substantial tumor shrinkage and 57.1% had disease control without further deterioration. The efficacy lasted for an average of 12.2 months. In addition, CA-125 levels improved in 23.8% of patients.
Ubamatamab is a human bispecific antibody that binds MUC16 on the surface of cancer cells to CD3-expressing T cells to promote T cell activation and release of cytotoxicity to kill cancer cells. The researchers say that MUC16 is expressed in about 80 to 90 percent of ovarian cancer patients.
Preclinical mouse experiments have shown that Ubamatamab combined with human immune cells has antitumor activity against intraperitoneal MUC16-expressing ovarian tumor cells and malignant ascites.
At present, the Phase 1 human trial is still in progress, and institutions participating in the trial include Memorial Sloan Kettering Cancer Center, Dana-Farber Cancer Institute, and Massachusetts General Hospital in the United States.
The study enrolled patients with recurrent advanced epithelial ovarian, primary peritoneal, or fallopian tube cancer who had received at least 1 line of platinum-based chemotherapy and had a CA-125 at least 2 times the upper limit of normal.
The average age of the enrolled patients is 61 years old, and they have received an average of 4.5 lines of treatment in the past. Histological subtypes include high-grade serous carcinoma, clear cell carcinoma, high-grade endometrioid carcinoma, and low-grade serous carcinoma. The average serum CA-125 level was 709 U/mL at the time of enrollment. In addition, 33% of patients
There were visceral metastases, and 58% of patients had PS2+ immunohistochemical staining greater than 75%.
Additional data showed that among patients with visceral metastases who received at least 20 mg of Ubamatamab, 20.7% had substantial tumor shrinkage, 72.4% had disease controlled without further exacerbation, and 31.0% had improved CA-125 levels.
Among patients with more than 75% of PS2+ immunohistochemical staining, 30.8% had substantial tumor shrinkage, 61.5% had disease control, and 46.2% had improved CA-125 levels.
At least 1 treatment-related adverse reaction of any grade occurred in enrolled patients in patients receiving any dose of treatment. 65.4% of patients had at least 1 adverse reaction of grade 3 or greater severity, 74.4% had grade 1/2 cytokine release syndrome, and 1 patient had
Immune effector cell-associated neurotoxicity syndrome.
The researchers noted that the data from the Phase 1 trial support more research into ubamatamab. Ubamatamab is also being studied as monotherapy and in combination with cemiplimab. In addition, subcutaneous administration of Ubamatamab is being studied to alleviate side effects.