Nab-Paclitaxel Outperforms Paclitaxel in NSCLC

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In a phase III study of 1052 patients, nanoparticle albumin-bound (nab) paclitaxel (Abraxane) produced significant improvement in the overall response rate compared with standard paclitaxel in the first-line treatment of patients with advanced non—small cell lung cancer (NSCLC). Both treatments were administered in combination with carboplatin. Investigators believe one reason why the trial met its primary endpoint is that the proprietary “nab” delivery system allows higher doses of paclitaxel to reach tumor locations than the standard formulation. Results of the randomized trial were submitted as a possible late-breaking abstract for the June annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago, Illinois.

The multicenter study included 102 sites worldwide, and its researchers consider it one of the largest NSCLC studies conducted to date. Said principal investigator Mark Socinski, MD, University of North Carolina Lineberger Comprehensive Cancer Center, in a press release, “This is exciting news for lung cancer patients and has important implications not only in late-stage cancer but also in earlier stages of the disease.”

In an interview with Socinski, he suggested the study might lead to practice changes down the road. “Given this data show superiority in response compared to the established treatment regime, these results show the potential for a new option for patients with NSCLC.” While exact details regarding trial outcomes will not be available until the June ASCO meeting, Socinski said, “The trial reached its primary endpoint… with regard to response rates.”

The prospects for FDA approval of Abraxane in NSCLC are enhanced by the trial’s special protocol assessment (SPA) status. SPA classification means that the FDA considers a trial’s design, clinical endpoints, and statistical analyses acceptable for approval provided the trial has a successful outcome. In this case, the FDA determined the demonstration of a statistically superior response rate to be a sufficient standard for submission of a supplemental new drug application (sNDA). With nab-paclitaxel outperforming paclitaxel, the path is clear for Abraxis to seek approval of nab-paclitaxel in combination with carboplatin as an initial treatment for NSCLC. Dr Socinski told Oncology & Biotech News, “Abraxis BioScience is planning to file an sNDA for Abraxane in this indication in early 2011.”

The treatment of lung malignancies would be the second FDA-approved indication for nab-paclitaxel. In 2005, the FDA approved the drug as an injectable treatment for metastatic breast cancer after failure of combination chemotherapy that has spread or relapsed within 6 months of adjuvant chemotherapy with a combination regiment. Other indications for nab-paclitaxel currently being considered include malignant melanoma, pancreatic cancer, gastric cancer, and expanded applications for metastatic breast cancer.