The U.S. Food and Drug Administration has approved AstraZeneca and partner Daiichi Sankyo's precision drug to treat a type of breast cancer, the health regulator said on Friday.

The treatment, jointly developed with the Japanese company, was branded as Datroway and approved for patients with an advanced form of breast cancer who had received prior treatment.

The list price of Datroway is $4,891.07 per vial, AstraZeneca said. It will be available to patients in the U.S. by prescription in about two weeks.

It belongs to a class of medicines called antibody-drug conjugates (ADCs), also known as "guided-missiles" because they are designed to target only cancer cells while sparing healthy cells, unlike conventional chemotherapy.

Gilead's Trodelvy also belongs to the same class of drugs.

AstraZeneca and Daiichi's first co-developed ADC, Enhertu, was first approved by the FDA in 2019 for a type of breast cancer and later expanded for use in multiple conditions.

In December, Datroway was approved in Japan to treat patients with a type of breast cancer who had previously received chemotherapy.

In a late-stage trial, the drug slowed disease progression in trial patients whose cancer could not be surgically removed or had spread beyond its origin, compared with patients who received other treatments such as chemotherapy.

AstraZeneca and Daiichi Sankyo entered into a global collaboration to jointly develop and commercialize the drug in July 2020, in a deal worth up to $6 billion.

The companies are also seeking approval for the drug in patients with a type of lung cancer with a mutated form of a gene called EGFR, who have previously received treatment.