SABCS: Pfizer's Ibrance backs up benefit in HER2-negative breast cancer with real-world data

Ibrance previously scored a nod to treat male breast cancer based largely on real-world data. (Pfizer)

SAN ANTONIO––In chasing down rare cancers, Pfizer has turned to real-world evidence as a tool to study hard-to-treat and minuscule populations. The drugmaker's Ibrance, which previously notched a breast cancer approval in men based largely on non-clinical data, is now touting more real-world data to support its case.

In a real-world study presented Wednesday at the San Antonio Breast Cancer Symposium, women with HR-positive, HER2-negative breast cancer lived a median of 19.1 months progression-free when treated with Ibrance and an aromatase inhibitor. 

By contrast, patients treated with the aromatase inhibitor alone lived without disease progression for a median 11.9 months, Pfizer said. Patients in the study were followed for a median 48 months.

Pfizer said the data––culled from electronic records on the Flatiron Health Analytic database, which includes 2.2 million U.S. patients––supported results from its Paloma-2 clinical trial that showed a significant benefit in adding Ibrance to aromatase inhibitors. 

Chris Boshoff, Pfizer Oncology's chief development officer, said the the study's support for previous clinical evidence was part of Pfizer's strategy to boost trial data with real-world observation in tricky-to-treat populations. 

"We are really employing a lot of effort and energy and resources to supplement our clinical trails with real-world data and see that real-world data create real-world evidence," Boshoff said.

RELATED: Pfizer uses real-world data to score Ibrance breast cancer nod in males

Although the most recent study pulled data from a large patient pool, Pfizer has previously used real-world studies as an entry point to observe smaller numbers of patients with rare breast cancer––particularly men. 

In May, Ibrance notched an FDA approval to treat male patients with HR-positive, HER2-negative breast cancer, based largely on real-world data pulled from electronic health records and post-marketing reports from the IQVIA Insurance database, the Flatiron database and Pfizer's own global safety database.

Pfizer said at the time that invasive breast cancer would affect 2,670 men in 2019.

Previously used largely to justify pricing decisions for payers, real-world data is increasingly becoming a tool for regulatory filings, thanks to the 21st Century Cures Act, which passed in 2016. For Pfizer, the FDA's growing appetite for real-world data has presented an opportunity to pursue indications that would be difficult to test just in the clinic, Boshoff said. Recruiting enough rare cancer patients for a comprehensive trial is time-consuming, costly, and sometimes simply fails.

"In that context, where approval is difficult, small cohorts of real world evidence can complement and supplement clinical data," Boshoff said. "We certainly do not think that real-world data will replace the gold standard of clinical trials, but we do think they can support the evidence we can generate in a clinical setting."