• Intro
• Commercial Plans
• Medicare Plans
• Prior Authorization
• Step Therapy
• Quantity Limits
• Strategic Implications and Questions

Featured article: Collateral Formulary Access Impact in the Sleep Disorder Class due to Patent Loss for Ambien

Executive Summary

While the impact on formulary access for a brand product losing patent protection is typically rapid and clear cut, the broader impact on remaining branded competitors within the therapeutic drug class is less clear. With the availability of a lower cost generic, plans may have greater flexibility to move existing brands to higher tiers or place new access restrictions, such as prior authorization or step therapy. In this edition of Fingertip Formulary Insights™, we examine the impact on formulary status in the sleep disorder category after Ambien lost its patent protection in April 2007. In prior editions of Fingertip Formulary Insights™, we examined the impact to the statin and antidepressant markets when prominent branded products lost their patent protection. Those two analyses showed different findings, with a far greater collateral impact seen in the statin market. Because there are unique clinical issues with psychotropic products, differences between therapeutic areas are not unexpected.

Methods

We utilized the Fingertip Formulary Analytics^® platform to understand the impact of newly available generic zolpidem (Ambien) on the formulary status of remaining single source branded products in the sleep disorders drug class. We examined formulary access as measured by tier 1 and tier 2 coverage, as well as managed care restrictions such as prior authorization, step therapy, and quantity limits, from January 2007 through April 2008. We segmented plans into “Medicare” and “Commercial” (i.e. commercial, PBM, Medicaid and others) categories. All results were analyzed as a percentage of covered lives.

Findings

• Commercial Market – the availability of generic zolpidem resulted in a significant decline in the tier 1/tier 2 availability of branded Ambien. The decline started immediately in April 2007 when Ambien had tier1/tier 2 availability of 59%, and extended through November 2007, when Ambien declined to 11% access. Sonata also declined in tier 1/tier 2 availability from 21% in April 2007 (30% in January 2007) to 17% in April 2008. However, Lunesta and Rozerem each gained access, with Lunesta experiencing the larger gain, increasing from 13% availability in April 2007 to 35% in April 2008. Rozerem increased its access more modestly from 9% to 12% during the same period.
• Medicare Market – Ambien experienced a similar loss in tier 1/tier 2 availability although formulary access was better in the Medicare market (as compared to non-Medicare) at the start and the decline was slower than the non-Medicare market. Ambien CR’s access also declined from 46% in April 2007 to 36% in April 2008. As with the commercial market, Lunesta appeared to successfully take advantage of Ambien’s patent loss by increasing its access from 34% of lives in April 2007 to 39% in April 2008. Sonata and Rozerem maintained their access during the study time period.
• Managed Care Restrictions – Commercial plans appeared to increase the percentage of lives subject to prior authorization and step therapy for all major brands after Ambien’s patent loss. In contrast, Medicare plans used step therapy as their primary control for branded drugs, with significant increases being seen for Rozerem and Ambien CR in particular.

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