Patients with BRCA-mutated metastatic breast cancer may benefit from olaparib
medwireNews: Olaparib delays disease progression by nearly 3 months compared with standard chemotherapy in patients with human epidermal growth factor receptor type 2-negative metastatic breast cancer and a germline BRCA mutation, results from the phase III OlympiAD trial show.
For the trial, 205 patients, who had received no more than two previous chemotherapy regimens for metastatic disease, were randomly assigned to receive treatment with the oral poly(adenosine diphosphate–ribose) polymerase inhibitor olaparib 300 mg twice daily. They were compared with 97 patients who were assigned to standard single-agent chemotherapy with the physician’s choice of capecitabine, eribulin, or vinorelbine in 21-day cycles.
As reported at the 2017 ASCO Annual Meeting in Chicago, Illinois, USA, patients receiving olaparib had a significant 42% lower risk for disease progression or death than those receiving standard therapy, with median progression-free survival at 7.0 versus 4.2 months, respectively.
At 12 months, 25.9% of the patients in the olaparib group and 15.0% of the patients in the standard-therapy group were free of progression or death.
Furthermore, the response rate was higher with olaparib than with standard therapy, at 59.9% versus 28.8%, but the median time to onset of a response was similar, at 47 and 45 days, respectively.
The researchers say this is “an important consideration for symptomatic or rapidly progressing patients.”
Overall survival was similar between the groups, at 45.9% with olaparib and 47.4%, with standard chemotherapy, but the authors note that the trial “was not powered to assess differences in overall survival,” and the findings are likely to be confounded by differences in subsequent treatment.
Mark Robson (Memorial Sloan Kettering Cancer Center, New York, USA) and colleagues also found that patients in the olaparib group experienced fewer grade 3 or higher adverse events than those in the standard chemotherapy group (36.6 vs 50.5%) and were less likely to discontinue treatment due to toxic effects (4.9 vs 7.7%).
They add that the safety profile of olaparib was similar to that observed previously, with nausea and anemia the most commonly reported adverse events.
Robson et al conclude: “Larger studies that investigate the differential treatment effects of olaparib among subgroups, particularly those defined according to hormone-receptor status or previous use of platinum-based therapy, would be helpful, as would a head-to-head study to determine the relative efficacy of olaparib and platinum-based chemotherapy.”
The findings are published in The New England Journal of Medicine.
By Laura Cowen
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