The U.S. Food and Drug Administration (FDA) has approved Amgen and Allergan’s Kanjinti (trastuzumab-anns), a biosimilar to Genentech’s Herceptin (trastuzumab), for all indications of its reference product — including as a treatment for HER2-positive breast cancer, the companies announced.

A biosimilar is a biological medical product that is nearly identical to an original treatment that’s already on the market, but usually at a significantly lower price. A different company will manufacture a biosimilar after the original product’s patent expires, but must first get regulatory approval.

The FDA approval means that people in the U.S. with HER2-positive breast cancer, or gastroesophageal junction adenocarcinoma, can now receive a potentially less expensive form of the HER2-targeting antibody with a similar safety and efficacy as the original product.

“Kanjinti is the third biosimilar from our portfolio to receive FDA approval, highlighting our long-term commitment to providing patients with serious illnesses access to high-quality biological therapies,” David M. Reese, MD, executive vice president of research and development at Amgen, said in a press release.

An engineered antibody, Kanjinti is designed to exhibit the exact same protein sequence, structure, and function as Herceptin.

But because biosimilars are are grown in cells and may show some differences from similarly designed products, regulatory agencies require extensive data showing that a biosimilar is equivalent to the original medicine.

Thus, the FDA’s decision was based on extensive biochemical and clinical data demonstrating that treatment with Kanjinti achieved similar clinical outcomes as Herceptin. This included a Phase 3 clinical trial (NCT01901146) for people with HER2-positive early breast cancer, in which Kanjinti showed a similar safety profile and efficacy as its reference product.

Kanjinti will now become available in the U.S. for the treatment of HER2-positive breast cancer — either before surgical treatment or after the cancer has spread — alone or in combination with other agents.

It also will be available, in combination with chemotherapy, for those with HER2-positive metastatic gastric or gastroesophageal junction adenocarcinoma who have not received prior treatment for their metastatic condition.

This biosimilar product has been available in Europe, for the same uses, since May 2018. It is sold as 150 mg and 420 mg powder concentrate to be reconstituted and administrated by infusion.

“Kanjinti is the second of four biosimilars from Amgen and Allergan’s collaboration to be approved by the FDA,” said David Nicholson, chief research and development officer at Allergan. “We are proud of the progress being made as we continuously strive to develop and deliver high-quality cancer therapies in collaboration with Amgen.”