Descriptive review and analysis of immunoglobulin utilization management from 2,548 prior authorization requests

Immunoglobulin (Ig) is a costly blood product prescribed as immune replacement or modulation therapy to treat a wide spectrum of medical conditions. While the FDA has approved Ig for a limited number of indications, there are multiple off-label uses that have demonstrated proven clinical benefit or are currently in various phases of clinical study. There are also diagnoses for which Ig is prescribed, but for which no evidence-based efficacy data are available. Many conditions for which Ig has been prescribed are extremely rare, and a controlled clinical trial is not logistically possible. These conditions may be denied insurance authorization because of limited medical evidence that supports the use of Ig in their treatment. This limited evidence consists of uncontrolled studies, case series and reports, and expert opinion. Limiting the use of Ig therapy to cases with the best supporting evidence may control health care expenditure, but it may also limit the potential body of knowledge from publications by physicians with experience in treating these conditions. Specialty pharmacy providers can collect longitudinal outcomes, and data from their publications could provide support for improved managed care criteria or areas of future medical research.

To (a) assess levels of supporting evidence by diagnosis for a sample of Ig requests submitted through the managed care prior authorization (PA) process and (b) provide a descriptive review of such requests and resultant benefit coverage determinations by individual diagnosis, overarching diagnostic category, patient age group, and assessed levels of evidence.

Through collaboration with 6 health plans, we obtained and analyzed 2,548 managed care PA requests for Ig therapy received between February 2008 and August 2012, as well as resulting benefit coverage determinations. A literature review of 7 established treatment guidelines and expert consensus statements was conducted and used to evaluate all indications for Ig treatment presented among obtained requests and to assign each request to 1 of 5 categorical levels of supporting evidence.

Of the 2,548 Ig requests reviewed, 1,467 (57.6%) were found to be "supported" in the relevant literature; 830 (32.6%) were designated "conditional"; 127 (5%) were "lacking consensus"; 74 (2.9%) were "currently not supported"; and 50 (2%) were "undetermined." Overall, 2,094 (82.2%) of the requests were authorized by the health plans. Of the total requests, 1,633 (64.1%) were for FDA-approved diagnostic indications, of which 1,393 (85.3%) were authorized by the sampled health plans. The majority of requests for Ig were for treatment of neurological and immunological conditions. A total of 181 unique indications were identified, yet 833 (32.7%) of the requests were for just 2 indications-common variable immunodeficiency and chronic inflammatory demyelinating polyneuropathy. Patients aged 45 to 64 years represented 1,318 (51.7%) of all requests.

This analysis provides insight into the prescribed medical usage of Ig and the conditions for which it may be authorized through the managed care PA process. We identified 181 unique diagnostic indications for Ig, for which only 97 had established expert consensus. Although many diagnostic indications were identified, most requests were for indications with strong supporting evidence, and most of these were authorized by the health plans. The number of indications identified highlights the ongoing need for publications from physicians and specialty pharmacies with experience in treating these conditions in order to increase the body of knowledge surrounding use of this therapy.