After a rocky few months, Gilead's Trodelvy keeps recent winning streak rolling with priority review

It has been a tumultuous few months for Gilead Sciences’ breast cancer med Trodelvy. But after a surprise comeback at ESMO this year that reignited blockbuster hopes for the franchise, the antibody-drug conjugate is keeping its winning streak rolling.

Tuesday, Gilead said Trodelvy won an FDA priority review on its application in heavily pretreated HR-positive, HER2-negative breast cancer. The regulatory win sets up an approval action date by February 2023, Gilead said.

Gilead’s Trodelvy application leverages data from the closely watched TROPiCs-02 study, which the company notes met its primary endpoint of progression-free survival, plus a secondary endpoint of overall survival versus a physician-picked chemotherapy.

The FDA handed down the priority review tag just a few months after Gilead rolled out TROPiCs-02 data at the 2022 American Society of Clinical Oncology (ASCO) annual meeting in June and more recently trumpeted better-than-expected life extension benefit at last month’s European Society for Medical Oncology (ESMO) congress 2022.

Digging deeper into the TROPiCs-02 data, Trodelvy slashed the risk of disease progression or death by 34%. Further, the antibody-drug conjugate cut the risk of death compared to a physician-picked chemotherapy by 21%, helping extend patients’ lives by a median 3.2 months over the doctors’ choices.

“We’re hitting the upper end—if not exceeding—most of the expectations out there,” Bill Grossman, M.D., Ph.D., Gilead oncology’s therapeutic area head, recently told Fierce Pharma ahead of a presentation at ESMO 2022.

HR-positive, HER-2 negative breast cancer is the most common form of the disease and makes up some 70% of all new cases, or nearly 400,000 global diagnoses each year, Gilead estimates. For patients with metastatic disease, where Trodelvy is angling for approval, patients typically become resistant to endocrine-based therapy over time, often being relegated to single-agent chemotherapy.

“In this setting, it is common to receive multiple lines of chemotherapy regimens over the course of treatment, and the prognosis remains poor,” Gilead said in its release.

Trodelvy has weathered its share of ups and downs on mixed data readouts in HR-positive/HER-2 negative breast cancer this year.

While the med’s ability to stave off disease progression or death in TROPiCS-02 represented a statistically significant showing, its mere 1.5-month improvement on disease progression-free survival was disappointing.

But things started looking up for Trodelvy when its life extension data eclipsed certain industry watchers’ expectations. The data also met a perceived efficacy bar needed for Trodelvy to clinch at least $1 billion in peak sales in HR-positive/HER2-negative breast cancer, RBC Capital Markets analysts wrote in a note to clients last month.

Gilead has high hopes pinned on Trodelvy, which the company expects to chip in on its goal to generate a third of its revenue from oncology by 2030. Gilead got its hands on the drug as part of its $21 billion Immunomedics buyout back in 2020.

The drug currently boasts green lights in triple-negative breast cancer and bladder cancer. But Trodelvy’s biggest opportunity may lie in the HR-positive/HER2-negative field, analysts have previously speculated.

Meanwhile, Trodelvy is facing a major threat from AstraZeneca and Daiichi Sankyo’s HER2-targeted medicine Enhertu. With an industry-first HER2-low nod, Enhertu could challenge Trodelvy both in triple-negative breast cancer and potentially in the larger HR-positive/HER2-negative field. Enhertu is poised to become standard of care in breast cancer for a wide range of HER2 expression statuses and may eventually leap ahead of the Gilead drug in the treatment chain, two experts told SVB Securities in July.