First large, multicenter, open-label study utilizing HLA-B*5701 screening for abacavir hypersensitivity in North America.

A hypersensitivity reaction is associated with abacavir in approximately 2-8% of exposed patients. The frequency of the HLA-B*5701 allele varies across racial groups and significantly correlates with risk of hypersensitivity. Studies in Europe and Western Australia demonstrated that prospective screening can significantly reduce the rate of hypersensitivity by avoiding the use of abacavir in patients carrying the HLA-B*5701 allele. Prospective HLA-B*5701 screening in a large, racially diverse North American population resulted in less than 1% of individuals diagnosed with a suspected abacavir hypersensitivity reaction (ABC HSR) and no positive skin patch test through 30 weeks among HLA-B*5701-negative individuals.