By Maggie Fick
(Reuters) -AstraZeneca said on Friday its experimental precision drug had slowed the progression of a common type of breast cancer in a late-stage trial, a boost for the company after its shares fell in July on results from a separate trial of the same drug for lung cancer.
The drug, datopotamab deruxtecan, which AstraZeneca (NASDAQ:AZN) is jointly developing with Japan's Daiichi Sankyo, is being closely watched by analysts and investors in part due to the promise of the class of drugs to which it belongs, known as antibody drug conjugates (ADC).
ADCs consist of tumour-seeking monoclonal antibodies that are combined with a cell-killing chemotherapy payload.
The trial data released on Friday showed the drug, abbreviated as Dato-DXd, demonstrated a statistically significant and clinically meaningful improvement in slowing the progression of a type of breast cancer in trial participants, compared to patients who received other treatments such as chemotherapy.
The trial focused on tumours that grow in response to the hormones oestrogen or progesterone, which account for roughly two-thirds of breast cancer cases. The study participants's disease had spread to other parts of the body.
The British drugmaker also said that there was a "trend in improvement" in the other main goal of the study, "overall survival" of patients, but the data on that was not mature so the trial would continue as planned.
AstraZeneca shares rose 1.7% in early trading, to their highest level in more than five weeks.
AstraZeneca is simultaneously developing the drug for use in lung cancer, and while data from a separate late-stage trial released in July was positive, the market was concerned that the drug's benefits for use in lung cancer treatment might not as pronounced as hoped, leading shares to fall more than 6% on the day the data was released.
The company has not said when it will release detailed data from the lung cancer study.
Analysts see the positive results from the breast cancer trial as good for AstraZeneca, but the market is more focused on the results of a trial called MARIPOSA by Johnson & Johnson (NYSE:JNJ). It compares AstraZeneca’s blockbuster cancer drug Tagrisso alone with its own drug, Rybrevant, in combination with another medicine.
Those results are expected later this year.