Gene-targeted drug slowed growth of prostate cancer

Tumors shrank in one-third of participants in a study, all of whom had untreatable cancer.

By Stephen Feller

LONDON, Oct. 29 (UPI) -- A precision drug, designed to treat tumors with specific genetic mutations and used to treat women with inherited cancers, was shown to benefit men with untreatable prostate cancer, according to a recent clinical trial.

Olaparib affected cancer in one-third of men in a clincial trial, including some who did not have a genetically-inherited form of cancer but whose tumors had mutated nonetheless.


Researchers said the modest success of the trial shows potential for crossover research because of genetic similarities between prostate, breast, and ovarian cancers.

"Our trial marks a significant step forward in the treatment of prostate cancer, showing that olaparib is highly effective at treating men with DNA repair defects in their tumors," said Dr. Johann de Bono, head of drug development at the Institute for Cancer Research, said in a press release. "It also proves the principle that we can detect prostate cancers with specific targetable mutations using genomic sequencing to deliver more precise cancer care by matching treatment to those men most likely to benefit."

Researchers enrolled 49 patients with treatment-resistant advanced prostate cancer -- all of whom were expected to survive for 10 to 12 months -- giving them a 400 mg dose of olaparib twice a day.


Of the participants, 14, or 33 percent, showed a clinically significant response to the drug. Responses were determined by researchers based on prostate cancer growth stopping, lasting falls in prostate specific antigen levels, falls in circulating tumor cell counts in the blood, and radiological responses on CT scans and MRI.

"It is very promising," Dr. Joaquin Mateo, a researcher at the Institute for Cancer Research, told the BBC. "Those entering the trial had an expected survival of 10 to 12 months and we have many patients on the drug for longer than a year."

The study is published in the New England Journal of Medicine.

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