If you haven’t noticed, there is a good bit of action occurring on the plaque psoriasis treatment front. One long-used anti-TNF drug (Cimzia®) may be nearing approval of its psoriasis indication, one new interleukin drug was recently approved (brodalumab), and another interleukin inhibitor is being considered by the U.S. Food and Drug Administration for approval later this year (guselkumab).
The general idea that the interleukin inhibitors have superior efficacy to the anti-TNF agents is becoming more accepted, but this is rarely reflected in the formulary preferences of health plans and insurers. Typically, these plans prefer both adalimumab (Humira®) and etanercept (Enbrel®). As with most therapeutic classes, this is the result of marketshare and net cost. AbbVie maintains the number 1 position, meaning that forcing a change or encouraging the use of an alternative preferred product is more difficult—moving significant marketshare to another agent will take considerable resources, and competitors’ pricing may not justify this battle.
There is evidence that etanercept is not the most efficacious of the anti-TNF inhibitors for the treatment of moderate-to-severe psoriasis, but few health plans manage the autoimmune category by specific indication (other than arming themselves with the usual prior authorization criteria). For instance, it may be a stretch to assume that FDA approval of a new psoriasis indication for a covered biologic will suddenly force plans to change its formulary positioning of the product.
Assuming that the interleukins do represent a better chance for complete resolution of plaque psoriasis symptoms (i.e., PASI 100 vs. PASI 75), albeit at a higher net cost, it means that biosimilars for etanercept or adalimumab won’t change the clinical outlook for patients. For example, a new study announced at this week’s American Association of Dermatology meetings found that Lilly’s interleukin-17A inhibitor ixekizumab (Talz®) beat Janssen’s interleukin-12/23 inhibitor ustekinumab (Stelara®) in a head-to-head trial. The point is that anti-TNFs cannot match this level of efficacy (based on PASI scores): 83% of those treated with the interleukin-17A product achieved PASI 90 scores compared with 59% of those treated with the comparator; 49% of those treated with interleukin-17A achieved PASI 100 scores compared with 23% of those treated with the interleukin-12/23 inhibitor.
Yet health plans have not decided that the clinical benefits of the interleukins outweigh their higher costs, making them preferred products or available as first-line biologic agents. Marketshare and price are the usual sticking points.
Furthermore, the basic problem of biosimilar pricing still remains. In personal correspondence with several health plan pharmacy directors, the 15% discount offered for Pfizer’s Inflectra®, the only biosimilar anti-TNF available, is easily matched by Janssen for its Remicade® originator. Health plans could actually wind up paying more for an aggressive campaign to replace the originator brand with the biosimilar at current pricing.
This will certainly play a role in deciding whether Enbrel® can be knocked off its preferred positioning perch. With billions of dollars in annual revenue at stake, Amgen will surely take measures to match any modest discount from Sandoz on biosimilar etanercept (or at least get closer to that net-cost neighborhood with increased rebates). This may well be all that is needed to discourage biosimilar uptake on drug formularies.