By Carl Reed

Frequently called super aspirin, COX-2 inhibitors (COX-2s) are a type of selective nonsteroidal anti-inflammatory drug (NSAID) used to treat arthritis, dysmenorrhea, and acute pain.  More than 30 percent of anti-inflammatory prescriptions are being written for COX-2s, based on market data.  The COX-2s currently on the market are listed in Figure 1: AWP Comparison of Commonly Prescribed Anti- inflammatories.

Amidst pharmaceutical manufacturer claims of greater efficacy and stronger safety profiles, COX-2s are a costly alternative to traditional NSAIDs.  To date, clinical literature has not shown COX-2s to be any more effective for the above conditions than lower cost NSAIDs. 

Rofecoxib is the only COX-2 agent on the market that the U.S. Food and Drug Administration (FDA) has allowed the claim for a lower incidence of serious upper GI adverse events including major bleeding, perforation, and obstruction.  The other COX-2s cannot make this claim.  While rofecoxib may offer greater GI safety than other COX-2s, the FDA required wording about the cardiovascular risks associated with taking the drug.

  Clearly, physicians must be careful in prescribing NSAIDs for older patients, patients taking anticoagulants and those patients with prior GI events. Because COX-2s are generally unnecessary in patients (including patients with diabetes) who are taking aspirin prophylactically for cardiovascular disease, the actual target population that needs costly COX-2s may be smaller than reported.

Cost Comparisons

Maximum Allowable Cost (MAC) listings for traditional NSAIDs and Average Wholesale Price (AWP) listings for COX-2s are included in Figure 1.  It is extremely difficult to develop an exact daily cost of consumption equivalent for COX-2 therapies.  Rofecoxib and valdecoxib are indicated for once daily usage while celecoxib is once or twice daily. Under these parameters, rofecoxib is the least expensive based upon straight AWP.  When comparing these costs to the AWPs for traditional NSAIDs, COX-2s are more expensive across the board.

Cost Containment Strategies

Assuming your organizationÕs clinicians agree that COX-2s do not offer significant benefit over more traditional therapies, expenses in this class may be controlled by implementing Prior Authorization guidelines.  The goal of doing this is to ensure these drugs continue to be available to those that truly need them and to reduce the use of these drugs by people whose needs may be met by traditional NSAIDs.  For example, prescription authorization for COX-2s could be granted if the patient meets one or more of the following conditions:

• Taking warfarin,

• Over age 65,

• Taking medicine indicative of a GI issue (i.e., proton pump inhibitor),

• Known to have experienced a past GI event, or

• Known to have tried at least one or two NSAIDs that were not shown to be effective and/or tolerated.

Another successful cost containment strategy for COX-2s is to place them on the third or higher tier in a multi-tier formulary.  Patients will, to some degree, prefer drugs that are available with lower copays.

Reed is Director of Pharmacy for Preferred Care, a New York HMO with more than 200,000 lives. He is also a member of the New York State Medicaid Pharmacy & Therapeutics Committee.

Additional References

Schoenfeld, P. "An evidence-based approach to the gastrointestinal safety profile of COX-2-selective anti-inflammatories." Gastroenterology Clinics of North America. 2001;30(4):1027-1043.

 Oregon Health Policy & Research: review of NSAIDS and COX-2 inhibitors @ http://www.ohppr.state.or.us/

 Rx Intelligence @ http://rxintelligence.com/news/upcoming.htm

 Simon, LS. "COX-2 Inhibitors: are they nonsteroidal anti-inflammatory drugs with a better safety profile?" Gastroenterology Clinics of North America. 2001;30(4): 1011-1025

 Silverstein, FE; Faich, G; Goldstein, JL; et al. "Gastrointestinal toxicity with celecoxib vs. nonsteroidal anti-inflammatory drugs for osteoarthritis and rheumatoid arthritis. The CLASS study: a randomized controlled trial." JAMA. 2000:284:1247-1255.

Whelton, A; Fort, JG; Puma, JA; et al. ÒCyclooxygenase-2-specific inhibitors and cardiorenal function: a randomized, controlled trial of celecoxib and rofecoxib in older hypertensive osteoarthritis patients." American Journal of Therapeutics. 2001;8:85-95.

 Fitzgerald, GA and Patrano, C. "The coxibs, selective inhibitors of cyclooxygenase-2."

New England Journal of Medicine. 2001:345(6):433-442.

FDA Talk Paper: "Labeling Changes for Arthritis Drug Celebrex". June 7, 2002.

FDA Talk Paper: "FDA Approves New Indication and Label Changes for the Arthritis Drug, Vioxx". April 11, 2002.

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