Immune response to pneumococcal polysaccharide vaccine in adults with chronic XXXX treated with alefacept.

@entity1 @entity2286 @entity1569
BACKGROUND: Alefacept is a T cell-modulating biologic therapy for @entity1569 that could affect @entity1 ' ability to mount immune responses. OBJECTIVE: This open-label, phase IV, multicenter study assessed the ability of adults with chronic @entity1569 receiving alefacept to generate antibodies to a pneumococcal polysaccharide vaccine ( @entity2286 ). METHODS: @entity1 were treated with a standard 12-week course of alefacept and administered the 23-valent @entity2286 at week 6. Antipneumococcal antibodies were measured at baseline and weeks 6, 9, 12, and 33. The primary end point was the percentage of @entity1 with a 2-fold or greater increase from prevaccination (week 6) to 6 weeks postvaccination (week 12) in antibody titers to 2 or more of 5 designated PPV antigens. RESULTS: Of 43 @entity1 enrolled, 42 were included in the full analysis set, with 86% of @entity1 exhibiting a 2-fold or greater increase and 57% of @entity1 exhibiting a 4-fold or greater increase in antibody titers to 2 or more of 5 designated antigens from prevaccination to 6 weeks postvaccination. At 6 months postvaccination, 78% of @entity1 had a 2-fold or greater increase and 47% of @entity1 had a 4-fold or greater increase in antibody titers to 2 or more of the 5 designated antigens. There were statistically significant increases in mean antibody titers to all 23 antigens in @entity2286 from prevaccination to 6 weeks postvaccination. LIMITATIONS: This was an open-label study with no comparator. CONCLUSIONS: Most @entity1 mounted immune responses to @entity2286 ; increases in antibody titers in these @entity1 were consistent with those seen in healthy individuals.
