May 31, 2014 | by Hiu Chung So
For women with ovarian cancer, the results of recent study could mean new hope for future treatments. The findings, reported at the American Society of Clinical Oncology's annual meeting, found that a combination of two experimental drugs, olaparib and cediranib, significantly lengthened the duration of progression-free survival compared to olaparib alone and standard chemotherapy.
The phase II trial is the first time that a PARP inhibitor is combined with an anti-angiogenic drug to treat ovarian cancer. PARP inhibitors such as oliparib work by thwarting cancer cells' ability to repair their own DNA, while anti-angiogenic drugs such as cediranib halts growth of new blood vessels in tumors.
"The significant activity that we saw with the combination suggests that this could potentially be an effective alternative to standard chemotherapy," said the study's lead author Joyce Liu, M.D., M.P.H., in a press release.
Liu, an instructor in medical oncology at Dana Farber Cancer Institute, added that these findings showed that the two drugs worked synergistically and bolstered each other's effectiveness against the cancer.
For this clinical trial, Liu and her colleagues randomized 90 patients with recurrent, platinum-sensitive ovarian cancer into either olaparib-only or olaparib+cediranib groups. In their analysis, they found that progression-free survival was significantly higher in the combination group, over 17 months compared to nine months in oliparib only. Meanwhile, previous trials with standard chemotherapy in this population showed a progression-free survival range from eight to 13 months.
Additional analyses also showed that the olaparib+cediranib group, in comparison to olaparib-only group, exhibited greater tumor shrinkage (80 versus 48 percent) and had more participants show a complete remission of the disease (five out of 44 versus two out of 46).
"Both of these drugs have been previously shown to have activity in ovarian cancer, and they are generally well tolerated and are easy to administer because they are taken orally," said Morgan, who is not involved in this research. "The difference in progress-free survival between the two regimens is greater than has been previously reported for the single agents. This suggests that the agents are potentially synergistic, although that must be shown in a more conclusive trial."
Morgan suggested that such a trial might compare the olaparib+cediranib combination against the two drugs given sequentially.
Meanwhile, Liu noted these results won't change clinical practice in the immediate future since both drugs have yet to be approved by the Food and Drug Administration, but she said she is exploring options to conduct a more definitive phase III trial for this regimen.
This study's abstract (LBA5500) is available online on ASCO's website.
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