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Breast cancer drug could help more patients – The Journal

Doctors report new gain in breast cancer treatment

For the first time, a drug targeting a protein that stimulates breast cancer growth has been shown to be effective against tumors containing very low levels of the protein.

It is not a cure. But this latest gain for targeted cancer therapy could open up new treatment possibilities for thousands of patients with advanced breast cancer.

Until now, breast cancers have been classified as HER2-positive – cancer cells contain more protein than normal – or HER2-negative. Doctors who reported the breakthrough on Sunday said it would make “HER2-low” a new category to guide breast cancer treatment.

About half of patients with advanced breast cancer previously classified as HER2-negative may in fact be HER2-low and eligible for the drug.

The drug is Enhertu, an antibody-chemotherapy combo given by IV. It finds and blocks the HER2 protein on cancer cells, while unloading a powerful cancer-fighting chemical inside those cells. It belongs to a relatively new class of drugs called antibody-drug conjugates.

The drug was already approved for HER2-positive breast cancer, and in April the Food and Drug Administration granted it breakthrough status for this new group of patients.

In the new study, the drug made patients live longer without their cancer progressing and improved survival compared with patients receiving standard chemotherapy.

The study compared Enhertu to standard chemotherapy in around 500 patients with HER2-low breast cancer that had spread or could not be treated with surgery. The drug stopped cancer progression for about 10 months, compared to about 5.5 months in the group receiving regular care. The drug improved survival by about six months (from 17.5 months to 23.9 months).

“This is a practice-changing study,” said Dr. Sylvia Adams, who leads breast cancer care at NYU Langone Health and has enrolled several patients in the study. “It addresses a major unmet need for patients with metastatic breast cancer.”

Going forward, it will be important to define the HER2 gray zone to ensure the right patients receive treatment, and then monitor them closely, experts said.

The drug, which costs around $14,000 a month, can lead to serious complications. Three patients in the study died of lung disease which is a known hazard of the drug. Physicians should ensure that patients report breathing problems immediately so that the drug can be stopped and patients treated with steroids.

The findings were presented Sunday at the American Society of Clinical Oncology annual meeting in Chicago and published by the New England Journal of Medicine. Funding for the study came from Tokyo-based Daiichi Sankyo and UK-based AstraZeneca, who jointly developed the drug.

Patients take the drug until they can no longer tolerate it.

“Many people, including many patients, have never heard of HER2-low breast cancer,” said study lead author Dr. Shanu Modi of Memorial Sloan Kettering Cancer Center in New York. .

“We finally have a HER2-targeting drug that, for the first time, can target this low level of HER2 expression,” Modi said. “This drug actually helps define low HER2 breast cancer. This makes it, for the first time, a targetable population.”

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The Associated Press Health and Science Department is supported by the Howard Hughes Medical Institute Department of Science Education. The AP is solely responsible for all content.

This undated photo provided by Daiichi Sankyo and AstraZeneca in June 2022 shows a vial and packaging for their Enhertu, an intravenously administered antibody chemotherapy drug. (Daiichi Sankyo, AstraZeneca via AP)

This undated photo provided by Daiichi Sankyo and AstraZeneca in June 2022 shows the production of their Enhertu, an intravenously administered antibody chemotherapy drug. (Daiichi Sankyo, AstraZeneca via AP)

This undated photo provided by Daiichi Sankyo and AstraZeneca in June 2022 shows the production of their Enhertu, an intravenously administered antibody chemotherapy drug. (Daiichi Sankyo, AstraZeneca via AP)

This undated photo provided by Daiichi Sankyo and AstraZeneca in June 2022 shows a vial and packaging for their Enhertu, an intravenously administered antibody chemotherapy drug. (Daiichi Sankyo, AstraZeneca via AP)