May 22, 2016
Paul E. Sax, M.D., is director of the HIV Program and Division of Infectious Diseases at Brigham and Women's Hospital in Boston.
Insurance prior authorizations, or prior approvals (PAs) -- those dreaded forms clinicians have to fill out, usually triggered by prescribing a non-formulary drug -- are much on my mind these days. And most of it has to do with three letters, specifically "TAF."
As readers of this site probably know, there are now three tenofovir alafenamide (TAF)-based coformulations approved for HIV treatment, all theoretically available for prescription alongside the older tenofovir disoproxil fumarate (TDF)-forms. In comparative clinical trials, TAF has consistently had a more favorable effect on bone and renal health than TDF -- a benefit of considerable importance to older patients with HIV.
Why do I bring up these older patients? If you've been doing HIV clinical care for a while, your patient population is probably a lot like mine:
These characteristics mean that AIDS-related complications are very unlikely to happen. If I found out that one of my stable HIV patients were hospitalized after being struck by a meteorite or falling satellite, this would surprise me only a little more than if one were admitted with Pneumocystis pneumonia. If we consider the health concerns of these individuals, non-AIDS diseases are far more likely to occur than those related to HIV.
And while we clinicians can't control the random showering of space debris, we can try to minimize drug toxicity -- which brings me back to the TAF-based HIV treatments, and whether we should be using them, and in whom.
I'd argue that these older HIV patients are ideal candidates for TAF (as opposed to TDF) -based drugs, and I've found myself wanting to switch them from TDF to TAF multiple times each week. Aging intrinsically leads to declines in renal function and bone density, and increases the likelihood that there will be comorbid conditions further impacting the kidneys and bones (hypertension, diabetes, menopause for women). Furthermore, a patient's lengthy HIV treatment often means that they have been on TDF for a long time -- probably the most important risk factor for clinically important TDF-induced toxicity.
This clinical reasoning, however, is currently lost on most of the payers, who have set up their favorite tool -- the "PA" (cue scary music here) -- to discourage use of these new drugs.
As far as I can tell, it's not that they have critically reviewed the data comparing TAF with TDF, and concluded that they disagree, or find it scientifically inaccurate. It's simply that the TAF treatments are new, and new means you have to jump through hoops to get it.
Or, even worse, you can't get it at all. Here's an email I received from a pharmacist trying to help me on one of these cases, this for a 70-year-old man with osteopenia currently on TDF/FTC in whom I thought TAF/FTC would be a safer choice:
The medication is not covered and is excluded from coverage because it is a new drug to market. [Insert payer or pharmacy management company here] said that a review for coverage is not possible and that an appeal would be denied outright. They also said that a letter of medical necessity would not help to obtain coverage, either.
Thank you! Have a nice day!
Glad he can be so cheerful!
Look, I get it -- drug costs are high, and PAs theoretically are a way of avoiding inappropriate use of new, more costly agents when older drugs would do the job just as well.
And though all three of the TAF formulations are cost-neutral to the older TDF treatments based on Average Wholesale Price, one has to assume there have been negotiations on price between the payers and manufacturers with TDF, deals that haven't yet been made with TAF. (Or made public to us or our patients -- "transparent" is never the word used to describe these deals.)
In addition, payers may well be looking forward to generic TDF, which is scheduled to become available next year and presumably would cost even less. It presumably will be easier to switch patients to generic TDF from branded TDF than from TAF, as a TAF to TDF switch could be viewed as switching to a potentially more toxic drug. Who would do that?
But are these mandatory PAs really the right way to decide whether a treatment is indicated -- based solely on whether it's new, and whether the clinician and his/her team have the endurance to fill them all out? Colleagues of mine delve deeper into the TAF vs TDF cost issues here, a welcome review of the relative values of these two drugs.
Meanwhile, over on an insurance company's web page, they list the reasons behind PAs as follows:
As far as I can tell, bullet #5 is by far the most common reason for a PA -- especially if the drug is new.
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