Health Rounds: Combo drugs improve on chemo alone for certain breast cancer patients

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(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays.)

By Nancy Lapid

(Reuters) -A newer class of cancer drugs can delay disease progression or extend survival for breast cancer patients, multiple teams of researchers reported at a major European oncology meeting.

The treatments, known as antibody-drug conjugates, or ADCs, combine a targeted antibody with a chemotherapy drug.

In the ASCENT-03 trial, researchers tested Gilead Sciences’ ADC Trodelvy in patients with untreated locally advanced or inoperable cases of aggressive triple-negative breast cancer who were not candidates for treatment with immunotherapy drugs such as Merck’s Keytruda.

Trodelvy combines the cancer-cell-targeting antibody sacituzumab with the chemotherapy drug SN-38.

With half of the 558 study participants followed for at least 13 months, those receiving Trodelvy had a median progression-free survival, or the time before the cancer began to worsen, of 9.7 months, compared to 6.9 months for those treated with standard chemotherapy, researchers reported at the European Society for Medical Oncology (ESMO) meeting in Berlin.

Earlier this year, study leader Dr. Sara Tolaney of the Dana-Farber Cancer Institute presented results of a related trial that showed Trodelvy also adds a benefit when such patients do meet criteria for immunotherapy treatment.

Separately, researchers from Memorial Sloan-Kettering Cancer Center in New York reported on Daiichi Sankyo’s Datroway, a combination of the antibody datapotamab and the chemotherapy drug deruxtecan, in patients with previously untreated advanced triple-negative breast cancer for whom immunotherapy was similarly not an option.

Among the 644 patients in the TROPION-Breast 02 trial, median overall survival was about 24 months with Datroway versus 19 months with standard chemotherapy, researchers reported.

Median PFS was about 11 months with Datroway and 6 months for standard chemo.

Meanwhile, two additional studies showed that ADCs can dramatically improve outcomes not only when the disease has already progressed, but also in patients with earlier-stage disease.

In patients with early-stage HER2-positive breast cancer in the DESTINY-Breast 05 and the DESTINY-Breast 11 trials, preoperative treatment with Enhertu from Daiichi Sankyo and AstraZeneca – a combination of the antibody trastuzumab and the chemo drug deruxtecan – improved disease-free survival compared with standard therapy.

BLOOD TEST CAN GUIDE INTENSITY OF CHEMOTHERAPY

A simple blood test could change how doctors decide who needs chemotherapy, and how intensive it should be, in patients with colon or bladder cancer, according to study results presented at the ESMO meeting.

More than 1,000 people with stage 3 colon cancer in one study had blood taken about six weeks after surgery to remove the tumor.

If tiny fragments of cancer DNA in the bloodstream, known as circulating tumor DNA, were not detected, patients were considered ‘low-risk.’ If ctDNA was present, they were deemed ‘high-risk.’

The intensity of their treatment was then guided by their ctDNA results, according to a report of the study published in Nature Medicine.

Low-risk patients were able to receive less chemotherapy, leading to fewer hospitalizations and a reduction in side-effects such as nerve damage, with only slightly lower cancer-free survival, the researchers said in a statement.

“Outcomes were excellent among the patients identified as low risk based on their ctDNA levels, with 87% remaining cancer-free three years after surgery,” the researchers said.

A separate international trial published in The New England Journal of Medicine found that blood tests for ctDNA can also help guide treatment with Roche’s immunotherapy Tecentriq (atezolizumab) in patients who have had surgery to remove bladder tumors that invaded the muscle.

“By selecting patients based on ctDNA, we see a benefit not only for disease-free survival but also for overall survival with (Tecentriq),” study leader Dr. Joaquim Bellmunt of Dana Farber said in a statement.

“This is the first time that an adjuvant immunotherapy trial has shown a benefit for survival in selected patients based on ctDNA testing.”

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(Reporting by Nancy Lapid; Editing by Bill Berkrot)