Iniparib plus chemotherapy increased OS in triple-negative breast cancer

ESMO 35th Congress

MILAN — Compared with chemotherapy alone, the addition of iniparib to chemotherapy increased OS by almost 5 months in patients with metastatic triple-negative breast cancer. Moreover, complete and partial response or stable disease for at least 6 months was achieved in 55.7% of women assigned iniparib compared with only 33.9% of women assigned chemotherapy alone.

John Pippen, MD, of Texas Oncology, Dallas, presented the results from a randomized, phase 2 study of iniparib plus chemotherapy (n=62) in comparison with gemcitabine/carboplatin plus chemotherapy (n=61) in women with metastatic triple-negative breast cancer.

Median PFS was 3.6 months in the gemcitabine plus carboplatin chemotherapy group vs. 5.9 months in the chemotherapy plus iniparib group (HR=0.59; 95% CI, 0.39-0.9; P=.012). “Probably the most striking,” Pippen said during a press conference at the ESMO 35th Congress, “is that OS was 12.3 months for chemotherapy plus iniparib arm vs. 7.7 months for the chemotherapy alone arm.”

No significant differences were observed in adverse events between the two therapies. The most frequently reported grade 3/4 adverse events were neutropenia, thrombocytopenia, anemia, fatigue and leukopenia.

“These data support the further study of the difference in variability that enhances the toxic effects on cancer from chemotherapy. This drug may prove to be valuable in triple negative breast cancer as well as other types of breast cancers,” he said.

According to Pippen, there are two ongoing phase 3 studies of iniparib — one in triple-negative breast cancer and one in squamous cell non-small cell lung cancer.

Triple-negative breast cancer accounts for about 15% of all breast cancer cases and there is a desperate need to identify effective agents for these patients. This trial suggests a clear superiority of the treatment combining chemotherapy with iniparib over chemotherapy alone. Such a clear superiority is not usually observed in a trial where only 120 patients have been recruited. This suggests that the drug might be very active. Questions that remain to be answered include whether the chemotherapy treatment tested in this trial is the best partner for iniparib. Pre-clinical data suggest that other agents such as cisplatin, cyclophospamide and anthracyclines might be very good chemotherapy drugs to be combined with iniparib. The issue of identifying the best chemotherapy treatment to be combined with iniparib is still an open question. This and other questions are currently being investigated in ongoing trials.

– Angelo Di Leo, MD
Head of Sandro Pitigliani Medical Oncology

For more information:

Pippen J. #LBA11. Presented at: the ESMO 35th Congress; Oct. 8-12, 2010; Milan, Italy.

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