AstraZeneca-Daiichi breast cancer treatment shows promise in latest study

(Reuters) - An experimental breast cancer drug being developed by British drugmaker AstraZeneca and Japan’s Daiichi Sankyo’s met its main goal in a mid-stage study, bolstering their position in a highly competitive oncology market.

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AstraZeneca agreed in March agreed to pay up to $6.9 billion to work with Daiichi on the drug known as trastuzumab deruxtecan, in a direct challenge to Roche.

The treatment, also known as DS-8201, demonstrated a clinically meaningful response in patients who have metastatic breast cancer and a type of protein on the surface of cancer cells, the two companies said on Wednesday.

It targets the HER2 protein, a major trigger of uncontrolled cell growth in about 20 percent of breast cancers. It is an area where Roche, the world’s biggest cancer drug maker, has been a pioneer with its best-seller Herceptin.

“While positive data will have been expected given the phase I data, this is good news for (AstraZeneca) as it adds validation to a major transaction that initially disappointed the market,” Liberum analyst Alistair Campbell said in a note.

Analysts and investors had voiced scepticism over the price tag of the deal funded in part by the proceeds of a $3.5 billion share issue.

In the Phase II study, trastuzumab deruxtecan was evaluated in patients with HER2-positive metastatic breast cancer that could no longer be helped with Roche’s Kadcyla, AstraZeneca and Daiichi said in a joint statement.

Liberum’s Campbell predicts trastuzumab deruxtecan could reach $5 billion in drug sales globally for AstraZeneca and Daiichi. Herceptin generated about $7 billion in 2018.

The positive results from the study also underscore AstraZeneca’s bet on cancer medicines, an area of increasing focus after years of crumbling sales due to patent losses on older drugs.

Daiichi and the British drugmaker said they planned to seek approval for the drug with the U.S. Food and Drug Administration in the second half this year.

DS-8201 is part of a drug class called antibody-drug conjugates (ADC), which link powerful cell toxins to antibodies that cling to cancer cells, sparing the healthy cells that are damaged during conventional chemotherapy treatments.

There are wide ranging DS-8201 patient trials under way, five of which are at a final stage where results may be used in requests for marketing approval.

Reporting by Pushkala Aripaka in Bengaluru and Ludwig Burger in Frankfurt; Editing by Gopakumar Warrier/Keith Weir