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Nab-paclitaxel, an albumin-bound form of paclitaxel delivered in a nanoparticle, has shown a high response rate in a phase II evaluation of women with recurrent ovarian, peritoneal, or fallopian tube cancers.
"In these patients with platinum-sensitive cancers, we determined that there was a 64% overall response rate, so the drug is very active in this disease, and toxicities were minimal and manageable," Dr. Michael G. Teneriello reported in a poster.
Nab-paclitaxel (Abraxane) is a Cremophor-free, injectable suspension that the Food and Drug Administration approved in 2005 for the treatment of advanced breast cancer. These preliminary efficacy and toxicity results are the first in patients with platinum-sensitive recurrent disease, said Dr. Teneriello, Texas Oncology P.A., central Austin.
The researchers tested a dose of 260 mg/m² IV every 3 weeks in 47 patients with a median age of 65.5 years (42-84 years). Nearly all had a platinum-free interval of 1 year or longer, and all had only one prior treatment with up-front chemotherapy. Women who received a taxane within the previous 6 months were excluded.
The investigators reported that the overall response rate among the 44 evaluable patients was 50%, including 13 complete responses (CR) and nine partial responses (PR). In patients followed by RECIST (Response Evaluation Criteria in Solid Tumors) only, overall response was 27% (one CR and two PR in 11 patients). In those followed by CA-125, overall response was 64% (five CR and two PR in 11 patients). Among patients meeting both RECIST and CA-125 criteria, it was 54.5% (seven CR and five PR in 22 patients). Median time to response was 1.8 months.
"Because nab-paclitaxel does not require the Cremophor vehicle, there's less toxicity, and the time of administration is reduced," Dr. Teneriello said.
"Neutropenia was the most common side effect, and we saw grade 3/4 neuropathy in [only] 9% of patients, which was reassuring because this drug is associated with neuropathy," he said. Other side effects included fatigue, diarrhea, and dyspepsia (2% each); and grades 1-2 alopecia (85%).
At the time 46 patients remained alive. One death was related to progressive disease. Response and survival analysis are ongoing, Dr. Teneriello said, adding that further studies are warranted. The study was supported in part by a grant from Abraxis BioScience Inc., a developer of Abraxane.
Teneriello M.G. et al. Results of a phase II evaluation of nanoparticle albumin bound paclitaxel (nab-paclitaxel) in platinum-sensitive patients with recurrent ovarian, peritoneal, or fallopian tube cancer. Abstract 5525.
Commentary |
This study by Teneriello et al. provides the first substantial data on a new taxane, nanoparticle albumin-bound paclitaxel (nab-paclitaxel), in ovarian carcinoma. It enrolled platinum-sensitive patients with recurrent disease. The reported activity was similar to that of paclitaxel. As with paclitaxel, they fall short of those reported with platinum-based regimens in the platinum-sensitive setting. Hence, platinum-based combinations would remain the standard of care unless platinum compounds are specifically contraindicated in a particular patient. The next logical step would seem to be an exploration of combinations with platinum compounds in either the platinum-sensitive setting or in front-line treatment. For this agent to assume a significant place in the therapeutic armamentarium, some specific advantage over paclitaxel other than simply length of infusion would need to be demonstrated. — J. Tate Thigpen, M.D.
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