In October, the FDA approved Abraxane for use with the chemotherapy drug carboplatin to treat patients with advanced non-small cell lung cancer (NSCLC). This approval was based on studies showing the drug can be effective in shrinking tumors.
“Non-small cell is the most common type of lung cancer, the leading cause of cancer death in the United States,” said Mark A. Socinski, MD, director of the Lung Cancer Section at the University of Pittsburgh, lead investigator of Abraxane phase II and phase III lung cancer trials, in a press release from Celgene, the drug’s manufacturer.
About 85 to 90 percent of lung cancers are NSCLC, according to the American Cancer Society. The organization estimates that there are about 226,160 new cases of lung cancer (both small cell and non-small cell) this year, and about 160,340 people will die from the disease in 2012.
“The FDA approval of Abraxane is exciting for healthcare professionals because it offers an important new treatment option for all types of non-small cell lung cancer patients, in an area that has seen few treatment advancements in recent years,” added Dr. Socinski.
A Mighty Drug from a Mighty Pine
Abraxane is the brand name for a form of paclitaxel, a natural substance that scientists originally discovered in the bark of a type of Pacific yew tree. Researchers found that paclitaxel helps inhibit cell division in cancers. Another common tumor-fighting drug is docetaxel, which also originates from yew trees.
In the 1980s, studies showed that paclitaxel was effective in slowing or stopping melanoma and ovarian cancer. But researchers were concerned that hundreds of thousands of trees would have to be destroyed annually to meet demand. By the late 1980s, scientists figured out a way to create a synthetic type of paclitaxel.
In 1992, the FDA first approved the use of paclitaxel in a drug called Taxol for use against ovarian cancer. In 1994, it was given the OK for breast cancer. In 2006, the FDA approved Taxol in combination with other drugs to treat lung cancer.
Abraxane vs. Taxane
Both Abraxane and Taxol are types of chemotherapy called taxanes. They prevent cells from dividing and growing. Abraxane differs from Taxol in the way it delivers the paclitaxel.
Taxol is a solvent-based and contains paclitaxel dissolved in polyoxyethylated castor oil. With Abraxane, paclitaxel is encapsulated in albumin, a human protein and one of the main proteins in egg white. Studies have shown that Abraxane is less toxic than Taxol. The albumin makes it more targeted and prevents allergic reaction. With Taxol, the solvents used to dissolve the paclitaxel in the bloodstream are highly toxic. Forbes magazine reported in 2009 that Taxol comes dissolved in a solvent that is so potent it melts standard IV tubing.
A regimen of pre-medication is required before Taxol treatment to combat the effects of the chemicals on the body. Abraxane does not use chemical solvents, so patients do not need to take any pre-medication and there are fewer side effects.
Side effects of Taxol include hair loss, diarrhea, and leukopenia (a decrease is the number of white cells). For some, however, Abraxane can cause side effects, and patients are advised to report all such incidents to a doctor or a nurse.
While both drugs are given intravenously, Abraxane takes less time to administer than Taxol—about 30 minutes compared to about three hours.
The benefits of Abraxane may account for its higher price. An article in June 2012 in Bloomberg News online said that Abraxane costs $4,000 to $5,000 per dose, according to the manufacturer. Taxol can cost less than $500 per dose. PharmStore.com lists Taxol at $447 for a 100 mg vial.
Meeting FDA Standards
To accept Abraxane for lung cancer treatment, the FDA wanted to see that it was at least as active as Taxol.
Research from the Lineberger Comprehensive Cancer Center at the University of North Carolina at Chapel Hill convinced the FDA to give its OK.
In this study, 1,052 NSCLC patients received either Abraxane or a solvent-based paclitaxel. The Abraxane patients had a higher overall response rate of 33 percent vs. 25 percent among patients taking solvent-based paclitaxel.
“The administration of nab-PC [Abraxane] as first-line therapy in patients with advanced NSCLC was efficacious,” said the study’s authors.
Fred Hirsch, MD, professor of medicine and pathology and associate director for International Programs at the University of Colorado Cancer Center in Denver, told the dailyRx News, "An interesting observation in the study was that patients with squamous lung cancer responded remarkably well to treatment with Abraxane plus carboplatin with a 68 percent improvement in response compared to the 'standard' treatment with Taxol plus carboplatin. The squamous lung cancer group of patients has even more unmet needs than the non-squamous lung cancer population as most treatment advances."
The scientists evaluated the safety of Abraxane in 1,038 patients. The most common reactions, reported in 5 percent or more, were neutropenia (a low white blood cell count), anemia (a deficiency in healthy red blood cells), and thrombocytopenia (a decrease in blood platelets).
Investigators noted, however, that patient survival did not differ much between the two sets of patients. Abraxane patients lived an average of about 12 months, while the solvent-based paclitaxel group lived an average of 11 months.
Celgene hopes to win approval to market it for several other types of cancer, including pancreatic cancer and melanoma. In November, Celgene published abstracts online of research showing that patients with metastatic melanoma had significant improvement from Abraxane treatment.
Also in November, The Food and Drug Administration Commissioner, Margaret Hamburg, told scientific advisers that the FDA is considering a faster pathway to bring drugs such as Abraxane to market.
The Lineberger study was published in the June issue of the Journal of Clinical Oncology.