In this study, 123 patients with triple-negative breast cancer were randomized to receive a commonly used, well-tolerated chemotherapy regimen (gemcitabine and carboplatin) or to receive chemo plus iniparib.
More than one-half of the women responded to the combination treatment (meaning the tumor volume decreased) versus only about one-third of those receiving chemo alone.
Women receiving iniparib plus chemo lived an average of 12.3 months compared to just 7.7 months in the chemo-alone group. This may not seen like very long in either group, but for this serious a cancer, it is impressive, the researchers noted.
This was a phase 2 trial. O'Shaughnessy, who is co-director of breast cancer research at Baylor-Sammons Cancer Center, US Oncology, and Texas Oncology in Dallas, said the results of a larger (about 500 patients) phase 3 trial should be available within one to three months.
"The whole field is still preliminary and we have to be careful not to overhype the results [as] we're waiting on the results of the phase 3 trial," she said. "Phase 2 was quite positive, but we really don't know if this is going to end up benefiting patients until we get to phase 3."
In her editorial accompanying the study, Carey agreed. "Both excitement and caution are appropriate in interpreting the trial," she wrote. "Some clear drawbacks should be noted." Among them, she said, were the small size of the study group, "imbalances at baseline" favoring the iniparib group, and the "unconventional" chemotherapy regimen. But caveats notwithstanding, she concluded, the results may herald improved therapy "for an underserved subgroup of patients with breast cancer."
O'Shaughnessy added that the drug was "extremely well tolerated [by patients]. It didn't seem to add any appreciable toxicity to chemotherapy."
In the meantime, she pointed out, a woman walking through a clinic door who is diagnosed with triple-negative breast cancer
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