Steven R. Feldman, MD, PhD
When I hear about a new drug for inflammatory skin disease that has a novel target, the first thing I do is Google what happens when you have a deficiency in that pathway. For OX40, the first thing that comes up is "inherited human OX40 deficiency underlying classic Kaposi sarcoma of childhood."1 That doesn't make this target seem appealing to me. While I might use a new drug targeting this pathway if other options fail, drugs targeting this pathway would not be my first choice, even if clinical trial safety data looked good. Clinical trials are powered to assess efficacy and common safety issues but tend not to be large enough to fully characterize rare risks.
Black box warnings on topical calcineurin inhibitors seem dumb to me. I think black box warnings on topical calcineurin inhibitors would be truly ridiculous, even laughable, except that laughing is not appropriate because these misguided warnings may be hurting our patients. These black box warnings on topical calcineurin inhibitors may exemplify the limitations of governmental bureaucracies. There doesn't seem to be a strong rationale for why these black box warnings were placed on topical calcineurin inhibitors initially. Why regulators haven't removed these black box warnings since then is baffling, as topical calcineurin inhibitors are considerably safer for patients than the alternative, topical corticosteroids. We have good evidence that topical calcineurin inhibitors do not cause cancer in our patients. The continued presence of black box warnings on these products may undermine the credibility of FDA-mandated black box warnings on other products.
Hedderson and colleagues state, in a study of cardiovascular events and atopic dermatitis, "VTE [venous thromboembolism] and DVT [deep vein thrombosis] IRs [incidence rates] were markedly higher in this study than have been observed in the general US adult population (VTE: 2.0 [current study] vs. 1.1; DVT: 1.6 [current study] vs. 0.66 per 1000 person-years." I think that's misleading. The difference of only 1 in 1000 doesn't seem like a markedly higher rate to me and it's also unlikely to be clinically meaningful. Even if there is some increased relative risk of some type of cardiovascular event, even if the rate is doubled, that doesn't mean we need to screen or intervene. We need to be mindful of the absolute risks and not be moved by relative risks. We need to see cost-effectiveness studies showing that an intervention is valuable before we conclude that we should be doing some screening or intervention to chase down and increase the relative risk for some potential adverse event.
Additional Reference
- Byun M, Ma CS, Akçay A et al. Inherited human OX40 deficiency underlying classic Kaposi sarcoma of childhood. J Exp Med. 2013;210(9):1743–1759. Doi: 10.1084/jem.20130592