New treatment for wet AMD

September 1, 2009

Evaluation of a new value-based treatment approach for wet AMD.

We evaluated a Phase II study which was designed to assess the effectiveness of intraocular brachytherapy in conjunction with VEGF inhibitor therapy as a treatment for subfoveal choroidal neovascularization. One treatment naive eye of each participant with subfoveal choroidal neovascularization was treated and 34 consecutive participants completed treatment with follow-up of at least 12 months.

Radiation therapy was administered using the Epiretinal Brachytherapy System (NeoVista, Fremont, CA), an intravitreal applicator containing a Strontium/Yttrium 90 (90Sr /90Yr) β-emitting isotope, referred to from hereon as 90Sr brachytherapy. The 90Sr applicator was inserted through a pars plana incision and, after vitrectomy, was held for 3 to 5 minutes over the neovascular AMD lesion until a dose of 24Gy was delivered to the lesion base.

The 90Sr brachytherapy was given in conjunction with two 1.25mg intravitreal injections of bevacizumab. The first intravitreal injection was given within 1 week before the 90Sr administration to the time of 90Sr administration, and a second injection was routinely given 1 month later.

Evaluating cost-effectiveness

Cost-effectiveness is defined by what a society is willing to pay for a particular healthcare service. It is typically measured using a cost-utility ratio, or money expended per QALY (quality-adjusted life-year) gained. The World Health Organization suggests that interventions costing less than approximately 1 x per capita GDP (US$ 46,600)/QALY are very cost-effective, and procedures costing less than approximately 3 x per capita GDP (US$139,800)/QALY are cost effective.1 The National Institute for Health and Clinical Excellence (NICE) in the UK views interventions as cost-effective if they have a cost utility ratio (CUR) of less than £20,000/QALY, with some exceptions made to include interventions up to £30,000/QALY.2

The direct medical cost incurred with 90Sr brachytherapy/bevacizumab treatment of neovascular AMD, including initial treatment and 12 years of follow-up treatments, is $11,227 if treated in an ambulatory medical center or $13,697 if in a hospital inpatient setting. If bevacizumab injections are administered 5x yearly (as demonstrated effective in the PRONTO study) from years 2 through 13, for a total of 62.3 doses, the total cost is $28,274. The third party insurer CUR for the intervention is $10,973/QALY.

While the value gain conferred by interventions across medicine is defined by the improvement in length-of-life and/or quality-of-life, the value gain for most ophthalmic procedures is defined by the improvement in quality-of-life alone. Nonetheless, the QALY is an outcome that takes into account both.

The primary direct cost most often not analysed by third party insurers is caregiver expense. Paid non-family caregivers account for 27.7% of the overall caregiver expense, resulting in an annual payment of $5548 per patient. Therapy also theoretically frees up the 72.3% of the non-paid cohort of caregivers so they can also undertake gainful employment, accruing $14,482 annually to the GDP in the form of newly created wages that otherwise would not be possible.