Unprecedented response rate in neoadjuvent trial for low-grade serous cancer

Cure Our Ovarian CancerNews, Research

A Phase 2 study of 15 women with low-grade serous ovarian cancer reported by investigators from the University of Texas MD Anderson Cancer Center found an “unprecedented response rate” with a new treatment.

The participants all had newly diagnosed advanced low-grade serous ovarian cancer that was too extensive for surgery. In many other types of ovarian cancer chemotherapy would be given to shrink the cancer and make surgery possible but this rarely works in low-grade serous cancer.

In this study researchers found that a new treatment combination worked much better than chemotherapy in shrinking tumours.

The study enrolled newly diagnosed low-grade serous ovarian cancer patients with advanced cancer too extensive to be considered for primary surgery. They were treated with Fulvestrant and Abemaciclib with the goal of shrinking the tumours for surgery.

At the time of the report at the 2022 annual meeting of the American Society of Clinical Oncology (ASCO) this week, best overall response demonstrated 9/15 (60%) patients with a complete or partial response (tumour shrinkage) and 6/15 (40%) with stable disease.

Of the 7 patients who have undergone interval cytoreductive surgery to date, 5/7 (71%) had no gross residual disease and 2/7 (29%) had optimal residual disease (no residual tumor larger than 1 cm). Thus far, 5 patients have transitioned to letrozole for maintenance.

Dr. Amanda Fader from Johns Hopkins Hospital, discussant of this study, stated, “This is the first neoadjuvant treatment trial in advanced ovarian cancer to omit cytotoxic chemotherapy with promising results.”

Further studies are planned to explore this new treatment option in more women, but the initial results are quite promising.

Cure Our Ovarian Cancer and STAAR Ovarian Cancer are proud supporters of The University of Texas MD Anderson Cancer Center’s low-grade serous cancer research program. Visit STAAR to make a donation to support their work.

About the treatments:

Fulvestrant is an estrogen receptor antagonist. Fulvesterant binds to estrogen receptor, changing the shape, which reduces the binding of estrogen to the cancer. It also has an effect on progesterone receptors.

Abemaciclib (Verzenio) is a CDK 4/6 inhibitor that blocks the activity of two proteins on cancer cells, CDK4 and CDK6 involved in cancer growth.

They currently have FDA approval for use in breast cancer.

A similar combination (Letrozole and Ribociclib) is also being investigated in a Gynecologic Oncology Group clinical trial for recurrent low-grade serous ovarian cancer in the United States. [Update August 2023 – read our summary of the initial results here]

Cure Our Ovarian Cancer’s Australian research partner ANZGOG (the Australia New Zealand Gynaecological Oncology Group) is also investigating Letrozole and Ribociclib in metastatic or recurrent low-grade serous ovarian cancer and other rare gynaecological cancers in Australia and New Zealand. Visit our Australian website to support ANZGOG’s low-grade serous ovarian cancer research.

Published: June 8th 2022

Content reviewed by Dr David Gershenson of The University of Texas MD Anderson Cancer Center who has provided updated results from the original ASCO abstract