A drug used to treat inherited cancers in women, particularly ovarian cancers, showed promising results in a clinical trial involving men with advanced-stage prostate cancer.
Prostate cancer is the most prevalent cancer in men and is said to be the sixth leading cause of cancer mortality among men in the world. The diverse molecular features of the tumor have been well recognized; however, existing treatments have not been molecularly classified up until now.
Researchers of a new study think that determining predictive biomarkers to come up with more accurate treatment would be beneficial. With this, they embarked on a study designed by TOPARP Protocol Development Group, called TOPARP-A, which is an open-label, two-stage study that comprised of a single group and performed in different sites.
The study involved a total of 49 men diagnosed with treatment-resistant, advanced-stage prostate cancer. They were administered with 400 mg of olaparib two times a day. Olaparib is the first medicine marketed for inherited cancer mutations. The administration of the drug was performed until the patients exhibited progress in radiologic findings, undeniable improvement clinically, as well as unsatisfactory side effects, retraction of consent, or death.
For stage one, 30 patients underwent the experiment, while for stage two, there were 15 participants. The study, which run from July 2012 to September 2014, was performed in seven different centers. One patient, however, was lost after one week of follow-up.
During the time of data collation, 70 percent or 35 patients had died. Only four patients remained in the study. The median survival and follow-up rates were 10.1 months and 14.4 months respectively.
During the course of the study, the researchers found that 16 or 33 percent of the patients had tumors with DNA-repairing defects as per genomic examination. Out of this group, 14 were said to have responded well to olaparib, deeming the drug beneficial for the majority of the study subjects.
Majority of the participants, who had limited treatment choices, exuded disease control far longer than expected.
"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 tumours," said Johann de Bono from The Institute of Cancer Research, London. He added that it backs up the principle that prostate cancers may be identified with particular targetable changes utilizing genomic sequencing to come up with more accurate management via matching treatments to those who would likely benefit from it.
The findings of the study have resulted in TOPARP-B, which is the second part of the research, wherein the participants would only include those with confirmed DNA repair mutations. Should this trial become successful, olaparib may be deemed the standard of treatment for advanced-stage prostate cancer and DNA repair impairments. de Bono said he hopes that it won't take long.
The study was published in the New England Journal of Medicine on Thursday, Oct. 29.
Photo: Day Donaldson | Flickr