Clinical Benefit of Breast Cancer Drugs Differs with Criteria

Most clinical trials supporting US Food and Drug Administration (FDA) approval of drugs for metastatic breast cancer over the past 13 years did not meet thresholds for substantial clinical benefit on two of three established measures, according to research presented at the San Antonio Breast Cancer Symposium in San Antonio, Texas.

“The American Society of Clinical Oncology Cancer Research Committee (ASCO-CRC), the ASCO Value Framework Net Health Benefit score version 2 (ASCO-NHB v2), and the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale version 1.1 (ESMO-MCBS v1.1) are validated tools which quantify the clinical benefit for cancer drugs,” researchers explained in their session abstract.

Investigators used the resources to assess the benefit of 28 clinical trials behind 18 breast cancer drugs approved between January 1, 2006, and June 30, 2019. ASCO-CRC criteria was used to score noncurative trials; the ASCO-NHB v2 and the ESMO-MCBS v1.1 were used to gauge the benefit of curative and noncurative trials.

At the time of drug approval, only 7% of trials reported improvement in overall survival and 14% reported significant improvement in quality of life, according to the study.

Among trials with patients with advanced breast cancer, 79% of trials met the threshold for substantial clinical benefit according to ASCO-CRC criteria. However, just 45% met the ASCO-NHB v2 threshold, and only 23% met the ESMO-MCBS v1.1 threshold.

Meanwhile, among trials with curative intent, researchers found even greater disparity: 25% met the ASCO-NHB v2 threshold, while 80% met the ESMO-MCBS v1.1 threshold.

“In patients with early breast cancer, low agreement observed between the ASCO-NHB v2 and ESMO-MCBS v1.1 suggest that the respective frameworks may require additional refinement to accurately capture substantial clinical benefit in the curative setting,” researchers wrote.

—Jolynn Tumolo

Reference

Tapia JC, Molto C, Bujosa A, et al. Clinical benefit of breast cancer drugs approved by the United States Food and Drug Administration. December 13, 2019.