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| Retinal pigment epithelial cells in RPE65-mediated retinal disease |
Back in March, I
wrote a piece regarding the coming impact of high ticket gene therapies on
healthcare budgets. December saw the FDA approval of Spark Therapeutic's
Luxturna™ (voretigene neparvovec), a unique treatment for biallelic
RPE65-mediated inherited retinal disease, a form of Leber's congenital
amaurosis, which results in early onset, progressive loss of vision.
Predictably,
Luxturna's approval has reopened the debate around the cost of leading edge
therapies. At around $850,000 to treat both eyes, Luxturna™ pricing is somewhat
lower than the $1 million plus price tag anticipated by industry analysts,
although it's still the most expensive drug in the US by list price.
Justifiable?
Perhaps. Gene therapy product approval is not a guaranteed path to riches. As with
other genetic disorders, the potential treatment population is small, being
around 1000-2000 sufferers in the US, with around the same number in Europe.
Moreover, Luxturna™ is a one-time treatment. While even modest uptake should
cover Spark's development costs, the overall return to Spark will be, by pharma
standards, unremarkable.
Spark appears pragmatic
in its approach to reimbursement, offering insurers rebates should patients
fail to achieve an agreed degree of benefit, although with only limited and
short-term study data available, defining a improvement for rebate purposes
will not be easy. Spark is also thought to be considering an annuity model, allowing
insurers to pay over time [see update of 12th January below].
So much for cost,
but what about value? Although not an easy calculation, tallying the lifetime benefit
accruing from reduced direct and indirect medical costs, increased individual
economic activity and quality of life improvement, might come close to
justifying Luxturna’s price tag.
A draft assessment published
by the Institute for Clinical and Economic Review published just prior to
Luxturna's approval concluded that, although likely to result in better
outcomes than standard care, Luxturna would probably not prove to be
cost-effective at an assumed acquisition cost of $1 million. Another crank of the spreadsheet incorporating
the actual drug price and post-approval efficacy data, particularly the
durability of benefit, could tip the balance in Luxturna's favour.
The UK's National
Institute for Health and Care Excellence (NICE) recently concluded that,
compared with the cost and risk associated with stem cell transplantation for
the treatment of adenosine deaminase deficiency–severe combined
immunodeficiency (ADA-SCID or "bubble boy" syndrome) GSK's gene
therapy, Strimvelis™, provided both the best treatment option and value for
money, despite its €594,000 (around
£505,000) price tag.
Although invariably
flawed, cost-effectiveness analysis needs to be at the centre of gene therapy
pricing and adoption debates. Such analyses may not always prove favorable, but
without an objective means of establishing fair pricing and reimbursement, gene
therapies could become out of reach for many patients. The commercial abandonment
of Glybera™,a gene therapy for lipoprotein lipase deficiency and announcement
of GSK's intention to abandon Strimvelis® (and rare disease therapy development
in general) are portents that should not be ignored.
Photo credit: National Eye Institute, National Institutes of Health.
