Adaptive Trials Cut Time to Effective Breast Cancer Therapies: Laura Esserman, MD, MBA

Adaptive platform trials like I-SPY (NCT01042379) have meaningfully accelerated the identification of effective breast cancer therapies, according to Laura Esserman, MD, MBA, director of the Carol Franc Buck Breast Care Center at the UCSF Helen Diller Family Comprehensive Cancer Center, who discussed the trial's impact and remaining barriers to broader adoption of adaptive designs in an interview at an Institute for Value-Based Medicine® event in San Francisco on August 11, 2026, hosted by The American Journal of Managed Care^®.

Complete Response Rates Have More Than Doubled

Esserman reported that complete or near-complete response rates among patients tested through I-SPY have risen from approximately 20% to 50%–60% since the platform began evaluating targeted treatments. The trial has also identified chemotherapy-free regimens for HER2-positive disease, prompting a shift away from surgery-first treatment sequencing toward using a preoperative window to assess whether a given therapy is working before proceeding to surgery.

End Point Selection Remains a Key Barrier

Broader adoption of adaptive trial design is limited primarily by the absence of validated early end points capable of predicting trial-level, not just patient-level, outcomes, Esserman said. She pointed to cardiology's use of blood pressure and cholesterol as early markers—credited with roughly halving fatal stroke and heart attack risk—as a model for what oncology has yet to achieve. Continued collaboration with the FDA on refining early end points could shorten drug development timelines from 8 to 10 years down to 2 to 3 years, she said.

“Look at what happened in cardiology, because you have blood pressure, because you have cholesterol,” Esserman explained. “You have early end points that have allowed us to drop the risk of dying of stroke or a fatal heart attack by half. If we don't do that, we are not going to make progress in the time frame that we need to make progress.”

Deintensification Is the Next Priority

Esserman also called for more rigorous data supporting treatment deintensification in patients with strong responses, including expanded use of circulating tumor DNA and other biomarkers to guide follow-up. Rather than layering novel immunotherapies onto decades-old chemotherapy regimens, she argued the field should work toward replacing chemotherapy outright for appropriate patients.