Cancer Treatment Today

Lay Summary: Abraxane is FDA approved every three weeks. I discuss weekly regimens.

In January 2005, the U.S. Food and Drug Administration (FDA) approved the chemotherapy drug Abraxane, a new formulation of paclitaxel, for treating advanced (metastatic) breast cancer. The approval is for second-line therapy—after another chemotherapy regimen has been used and has stopped working. After failure of combination chemotherapy for metastatic breast cancer or relapse within 6 months of adjuvant chemotherapy, the recommended regimen for ABRAXANE for Injectable Suspension (paclitaxel protein-bound particles for injectable suspension) is 260 mg/m2 administered intravenously over 30 minutes every 3 weeks.

Abraxane provides a new way to make paclitaxel dissolve in water. Instead of Cremophor, Abraxane uses albumin, a natural protein found in the body. A tiny bit of paclitaxel is suspended in each albumin particle. Because albumin is natural to the body, there is no need to take steroids before receiving Abraxane. And since taking Abraxane does not require taking pre-medication to reduce the risk of an allergic reaction, an Abraxane treatment averages 30 minutes compared with three hours for Taxol. This enables a higher dose and different pharmacokinetics. In a Phase III research study, Abraxane was compared directly to Taxol in 454 women. The results of a Phase III trial show that cancers responded better to Abraxane than Taxol and stayed under control longer. This patient failed Taxol but it is possible that she may respond to Abraxane wince its formulationa llows a higher paclitaxel dose. This study used every 3 seek dose of 260 mg.m2.

However, it appears that the patient is receiving weekly Abraxane. This is for weekly administration, while the prescribing information is for every three weeks schedule.

A study of 106 patient Phase II study of ABRAXANE in patients with advanced breast cancer whose disease had progressed while they were being treated with TAXOL® and Taxotere® responded to subsequent treatment with ABRAXANETM (albumin nanoparticle paclitaxel) was presented at the Annual Meeting of the American Society of Clinical Oncology (ASCO) in New Orleans. The Phase II study, sponsored by American BioScience, included 106 patients with progressive metastatic breast cancer whose disease had progressed while being treated with TAXOL or Taxotere in the metastatic setting, or had a relapse within 12 months of adjuvant taxane therapy. 15% of patients responded to ABRAXANETM treatment and 30% had no disease progression after six months. The tolerability of this weekly regimen was demonstrated by the finding of <1% grade 4 febrile neutropenia and no grade 4 non-hematological toxicities. Grade 3 taxane associated toxicities were few, with <4% Gr3 sensory neuropathy, <3% Gr3 fatigue, <1% Gr3 edema, no Gr3 nail changes, no Gr3 myalgia and arthralgia, <1% Gr3 tearing, and no Gr3 hypersensitivity or flushing.

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The tolerability of this nanoparticle form was evident by the finding that 95% of cycles were given at the protocol specified dose of 100 mg/m², and that 91% of the patients were able to receive 100% of the planned dose of ABRAXANE at 100 mg/m2 administered weekly over 30 minutes with no dose reduction. This study is apparently the source for dose and schedule seected for this member.

Experts assume that weekly Abraxane is sufficiently established so that it is being tested in a phase III trial agains Taxotere, without a 3 weekly arm.

M. R. Green et al, Abraxane®, a novel Cremophor®-free, albumin-bound particle form of paclitaxel for the treatment of advanced non-small-cell lung cancer Annals of Oncology 2006 17(8):1263-1268

Abraxane, Prescribing Information

Blum JL, O’Shaunessy JA, Sandbach J, et al. Weekly Nanoparticle Albumin Paclitaxel (ABI-007) Results in Long-Term Disease Control in Patients with Taxane-Refractory Metastatic Breast Cancer. Proceedings from the 29th ESMO Congress, Vienna Austria, October 29- November 2, 2004, (Abstract #112).

Shaughnessy J, Tjulandin S, Davidson N, et al. ABI-007 (ABRAXANE), a Nanoparticle Albumin-bound Paclitaxel Demonstrates Superior Efficacy vs Taxol in MBC: A Phase III Trial. Proceedings from the San Antonion Breast Cancer Symposium, December 2003, San Antonio TX, (Abstract #44).

Gradishar W, Krasnojon D, Cheporov S, et al. A Randomized Phase 2 Study of Weekly (W) or Every-3-Week (Q3W) ABI-007 (ABX) Versus Every-3-Week Docetaxel (TXT) as First-Line Therapy in Patients (Pts) with Metastatic Breast Cancer (MBC). Proceedings from 29th Annual San Antonio Breast Cancer Symposium (SABCS). Oral presentation December 17, 2006. Abstract 46