Mr. Lamb is a freelance pharmacy writer living in Virginia Beach,Va, and president of Thorough Cursor Inc.

Leading medications for allergies, heart failure, insomnia, and osteoporosis have recently lost or will soon lose patent protection and face competition from lower-cost, equally effective products.Among biopharmaceuticals, a widely used human growth hormone, 2 coagulation factors, an immunosuppressant, and a major rheumatoid arthritis treatment will also see their patents expire in the coming year. The biologics may or may not get competitors.

It may seem surprising that several of the drugs do not have competitors waiting in the wings, ready to hit pharmacy shelves the day the innovator's patent expires. In nearly all instances, however, at least one generic drug maker is currently petitioning the FDA to approve an unbranded version of a listed drug. To take just one example, Mayne Pharma has been seeking federal review of an Abbreviated New Drug Application (ANDA) for its version of irinotecan (Camptosar; Pfizer) since late December 2005.⁴

In other instances, federal court cases brought years before expected patent expiration are still being litigated, holding up the determination of a potential generic product's status. Again citing a single example, Novo Nordisk, which holds the patent on repaglinide and sells the drug under the brand name Prandin, sued Sun Pharmaceutical subsidiary Caraco for patent infringement in 2005 after Caraco filed an ANDA for repaglinide. The case has been before the courts since 2005 and is unresolved.⁵

Biopharmaceuticals require separate consideration in any discussion of generic drugs because the FDA has no process for certifying that 2 protein-based medications are similar enough to be rated as equally safe and effective. The lack of a biogeneric approval process has created a biopharmaceutical market in which patent expiration does not make a brand name product subject to generic competition. In realworld terms, this means that the epoetin alfa product that Amgen sells under the brand name Epogen competes only with the epoetin alfa product that Ortho Biotech sells under the brand name Procrit, even though the patents for both expired in 2004.

Legislation introduced in Congress earlier this year, the Access to Life- Saving Medicine Act (HR 1038), would change this by requiring the FDA to create simplified application and review processes for biologics that are very similar, if not identical, to existing licensed products. The legislation and its companion Senate bill were in committee at press time.

If passed in its current form, HR 1038 would allow products to be approved for marketing if they could be shown to be "comparable" in molecular structure and effect to those with existing licenses without first going through numerous clinical trials.⁶

For a table of blockbuster patent expirations and first-time generics from August 2006 to February 2008, and a table of biopharmaceuticals going off patent in 2007-2010, please see tables 1 and 2 (PDF).

References

1. Express Scripts. Drug Trend Report 2005. Available at: www.express-scripts.com/ourcompany/news/industryreports. Accessed April 4, 2007.
2. FDA. Electronic Orange Book. Available at: www.fda.gov/cder/ob. Accessed April 4, 2007.
3. Drugs@FDA Web site. Available at: www.accessdata.fda.gov/scripts/cder/drugsatfda. Accessed April 4, 2007.
4. Mayne Pharma (USA). December 19, 2005. Correspondence. Available at: www.fda.gov/ohrms/DOCKETS/dockets/05p0496/05p-0496-cp00001-01vol1.pdf. Accessed April 5, 2007.
5. Court refuses to dismiss shareholder of defendant from Novo Nordisk case. Pharm Law Industry. 2006;48:3.
6. The Access to Life-Saving Medicine Act. February 14, 2007. Representative Henry Waxman Web site. Available at: www.henrywaxman.house.gov/pdfs/biologicsbillsummary_2.14.07.pdf. Accessed April 5, 2007.