Menarini’s Oral SERD Gains First-Ever FDA Approval for Breast Cancer

After posting positive Phase 3 trial results, Menarini and its U.S.-based subsidiary, Stemline Therapeutics, announced that the FDA approved its oral SERD, Orserdu, to treat postmenopausal or male breast cancer patients with ESR1-mutated ER+, HER2- advanced or metastatic breast cancer with at least one line of endocrine therapy. The FDA’s decision marks Orserdu as the first and only oral SERD to treat breast cancer, providing an alternative option for eligible patients. 

Promising Results Supporting the Approval

The Phase 3 Emerald trial included 478 ER+, HER2- advanced/metastatic breast cancer patients who had received at least one prior line of endocrine therapy. The open-label study evaluated the safety and efficacy of Orserdu as a monotherapy in the general patient population and patients with estrogen receptor 1 (ESR1) mutations. 

Over the course of several years, Orserdu accomplished the intended primary endpoint of elongating progression-free survival (PFS), checking all the boxes for the FDA before the regulatory agency gave the drug its seal of approval. 

Orserdu is an oral selective estrogen receptor degrader (SERD), which means it blocks estrogen production. This mechanism is essential to its performance because certain types of breast cancer leverage estrogen to grow. 

CEO at Menarini Group, Elcin Barker Ergun, said, “The FDA approval of ORSERDU marks the first ever therapy for ER+, HER2- advanced or metastatic breast cancer patients with ESR1 mutations, and we are very proud to offer a targeted therapy addressing this huge unmet need.”

Menarini purchased the rights to Orserdu from Radius Health in July 2020 for $30 million upfront, with the potential for $320 million in milestones and royalties. With the recent FDA approval, Radius will reap the benefits just three years after striking the deal. 

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SERD’s Potential in the Breast Cancer Space

Orserdu’s approval is a first for oral SERDs, but the promising antiestrogen therapy class has made waves in the past in the breast cancer arena. Some of biotech’s biggest hitters have had their hands in the SERD pot, trying to leverage the mechanisms and technology to develop blockbuster cancer therapies.

Though not an oral SERD, AstraZeneca’s Faslodex gained FDA approval over 20 years ago as an injectable SERD to treat certain kinds of breast cancer. Revolutionary in 2002, a generic version has since hit the U.S. market, gradually sinking Faslodex’s blockbuster status.

Still, oral SERDs remain a topic of interest for several biotech companies that see their potential in breast cancer. AstraZeneca has an oral SERD in its pipeline after making an impact with its injectable predecessor. 

Unfortunately, several companies continue to struggle with oral SERD development, like Sanofi and its former candidate ​​amcenestrant. After less-than-stellar results from a Phase 3 trial, Sanofi announced in August that it would discontinue the product’s development. 

With all the struggles other biotech companies have seen with oral SERDs, Stemline and Menarini’s success with Orserdu is a breath of fresh air and provides a ray of hope for all the other oral SERDs in development. The company said Orserdu would be available very soon to help eligible patients across the U.S.

Author

Reed Slater