Cost considerations in the medical management of glaucoma in the US: estimated yearly costs and cost effectiveness of bimatoprost compared with other medications.

INTRODUCTION: The aim of this study was to evaluate the cost effectiveness of glaucoma treatment with bimatoprost compared with other intraocular pressure (IOP)-lowering medications in adult patients with chronic glaucoma or ocular hypertension (IOP of between 22 mm Hg and 34 mm Hg), from a US healthcare payers' perspective.
METHODS: Estimated yearly costs and cost per treatment success for 0.03% bimatoprost once daily (Lumigan) were compared with 0.5% timolol twice daily (generic), 0.005% latanoprost once daily (Xalatan) and the fixed combination of 0.5% timolol and 2.0% dorzolamide twice daily (Cosopt). The model was based on year 2003 medical resource costs (physician visits and drug acquisition costs) and treatment success rates from published clinical trials. The clinical measure utilised was the percentage of patients achieving target IOPs.
RESULTS: A higher percentage of patients achieved target IOPs with bimatoprost than with each of the other medications. At most target pressures, the cost per treatment success for patients starting treatment on bimatoprost was less than that for patients started on other drugs. This was true despite that, when looking at costs alone, the estimated yearly costs for bimatoprost (averaged over both patient success and patient failures) were similar to or greater than those for the other drugs. The greatest differences in cost per treatment success were seen at target pressures < or =15 mm Hg. For example, at a target pressure of 13 mm Hg, the cost per treatment success based on the model was 9238-10,229 US dollars for bimatoprost, 23,218 US dollars for timolol, 21,943 US dollars for latanoprost and 16,034 US dollars for timolol/dorzolamide. The incremental cost of achieving additional clinical success for bimatoprost ranged from 800 US dollars to 1,700 US dollars versus generic timolol, and from 300 US dollars to 3,100 US dollars versus timolol/dorzolamide. Bimatoprost was more effective and less costly than latanoprost.
CONCLUSION: In our simplified model of cost per treatment success based on responder rates at varying IOPs, the greater efficacy of bimatoprost resulted in a cost per treatment success that was generally lower for bimatoprost than for timolol, latanoprost or timolol/dorzolamide. This was most pronounced at target pressures <15 mm Hg.