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

A central theme of Pharmacy Times' annual updates on pending drug patent expirations and equivalent generic launches has been that subjecting blockbuster drugs to competition from unbranded products is increasingly and dramatically reshaping the US medication marketplace.^1,2 This trend is expected to continue for traditional, small-molecule drugs.

Table 1

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If recent discussions among federal legislators, the FDA, and drug manufacturers produce tangible results, seismic shifts in the biopharmaceutical sector of the drug market also will appear on the horizon. Bills allowing the FDA to develop mechanisms for reviewing and approving applications for follow-on biologics made progress in Congress in 2007.

Drug-agency officials approached members of business committees from the Senate and House of Representatives in early February to ask for a seat at the table if new legislation regarding the regulation of therapeutically and structurally similar biologics is introduced. Companies that make biopharmaceuticals are not opposed to generic biologics in principle; rather, they want to make sure that their original patented products are guaranteed adequate periods of market exclusivity.

Developments Among Traditional Drugs

When Pfizer's patent on Norvasc (amlodipine besylate) expired on the last day of January 2007, a generic equivalent produced by Apotex immediately went on sale. More than a dozen FDA-approved, unbranded versions of the calcium channel blocker that had once been the most-prescribed, best-selling antihypertensive in the United States are now available. Although Norvasc generated >$2.7 billion in sales for Pfizer with 40 million prescriptions in 2006, the company estimated last spring that sales would be half of that in 2007.^2,3

Similar dramatic losses of market share are likely to be reported for a number of blockbuster drugs that lost patent protection in 2007, including Ambien (zolpidem, sanofi-aventis), Coreg (carvedilol, GlaxoSmithKline), and Zyrtec (cetirizine, Pfizer). Table 1 shows that GlaxoSmithKline's Advair (fluticasone and salmeterol) and Avandia (rosiglitazone) are just 2 of the other top-grossing medications that will go off patent within the next 20 months.

Follow-on Biologics More Likely Than Ever

Currently, no generic biologics exist in the United States. Efforts to change that picked up steam last year when Rep Henry Waxman (D, CA) introduced HR 1038, the Access to Life-Saving Medicine Act, which would have required the FDA to create ways to license biologics that are very similar, if not identical, to existing licensed products.⁶ The Senate version of the bill, S 1695, was reported out by the Health, Education, Labor, and Pensions Committee but not acted on by the full chamber.⁷

Key sticking points for the legislation were the FDA's apparent unwillingness to aggressively pursue the authority to vet generic biologics and industry demands that patent terms for innovator biologics run 14 years instead of the bill's proposed terms of 12 years. Regulators, at least, now appear to be more receptive.

CongressDaily reported in the first week of February that FDA officials had discussed developing a legislative framework for follow-on biologics with senior members of the House Committee on Energy and Commerce and the Senate Finance Committee.⁸ That framework, according to an FDA official, would "include necessary provisions to ensure the safety and effectiveness of these biologic products for patients ... [and] adequate intellectual property protections to preserve continued robust research into new and innovative lifesaving medications."⁹

The agency is downplaying expectations for the initial discussions. During a question-and-answer session following his testimony on President Bush's budget proposal for Fiscal Year 2009, Michael Leavitt, secretary of the Department of Health and Human Services, told the Senate Finance Committee that "biologics are an important medical development. We'd like to see them expanded in their generic form. We're anxious to see a bipartisan proposal."¹⁰

Biopharmaceuticals set to go off patent within the next 3 years are listed in Table 2. Genotropin (somatropin, Pfizer), NovoSeven (coagulation factor VIIa, Novo Nordisk), and Humira (adalimumab, Abbott) were among the top 200 best-selling prescriptions in 2006. With no timeline announced for action on expanding FDA's authority to license generic versions, however, it remains unclear when these products can expect to face low-cost competitors.

Table 2

References

1. Faden, M. Patent expirations produce top-selling generic drugs. Pharmacy Times. August 2006. www.pharmacytimes.com/issues/articles/2006-08_3757.asp. Accessed February 7, 2008.
2. Lamb E. Top 200 prescription drugs of 2006. Pharmacy Times. November 2007. www.pharmacytimes.com/issues/articles/2007-05_4629.asp. Accessed February 7, 2008.
3. Pfizer Lowers 2007 Outlook on Norvasc. International Business Times. April 20, 2007. www.ibtimes.com/articles/20070420/pfizer-outlook.htm. Accessed February 7, 2008.
4. FDA Web site. Electronic Orange Book. www.fda.gov/cder/ob. Accessed February 7, 2008.
5. Drugs@FDA Web site. www.accessdata.fda.gov/scripts/cder/drugsatfda. Accessed February 7, 2008.
6. Detailed Outline: The Access to Life-Saving Medicine Act. February 14, 2007. Representative Henry Waxman Web site. www.henrywaxman.house.gov/pdfs/biologicsbillsummary_2.14.07.pdf. Accessed April 5, 2007.
7. Martino M. Senate HELP Committee passes bill to allow FDA approval of generic versions of biotechnology medications. Fierce Biotech. July 2, 2007. www.fiercebiotech.com/node/7470. Accessed February 7, 2008.
8. Johnson F, Edney A. CongressDaily. http://nationaljournal.com/about/congressdaily. Accesssed February 6, 2008.
9. Edney, A. CongressDaily. nationaljournal.com/about/congressdaily. Accessed February 5, 2008.
10. Hearings Before the Senate Committee on Finance, 110th Congress, 2nd Sess (2008) (testimony of Michael O. Leavitt, secretary, Department of Health and Human Services).