Does treatment with intermittent infusions of intravenous anti-D allow a proportion of adults with recently diagnosed immune thrombocytopenic purpura to avoid splenectomy?

This study explored whether repeated infusions of intravenous anti-D could allow adults with recently diagnosed immune thrombocytopenic purpura (ITP) who had failed an initial steroid course to postpone and ultimately avoid splenectomy. Twenty-eight Rh+, nonsplenectomized adults with ITP diagnosed within 1 to 11 months and platelet counts 30 × 109/L (30 000/μL) or below were enrolled. Anti-D was infused whenever the platelet count decreased to 30 × 109/L (30 000/μL) or below. “Response” was defined as a platelet increase of more than 20 × 109/L (20 000/μL) to more than 30 × 109/L (30 000/μL) within 7 days of treatment. Patients were a median 3.5 months from ITP diagnosis at enrollment and had received a median of 2 previous therapies, including prednisone in 26 of 28 cases. They were followed for a median 26 months. A total of 93% responded to their initial infusion of anti-D, and 68% repeatedly responded with counts maintained above 30 × 109/L (30 000/μL) using anti-D alone. Currently, 12 (43%) of 28 patients have been off all treatment for more than 6 months without undergoing splenectomy, 6 maintaining counts above 100 × 109/L (100 000/μL). Seven continue on treatment, 8 underwent splenectomy, and 1 was lost to follow-up at 10 months. One patient discontinued anti-D because of toxicity. Patients with platelet counts at least 14 × 109/L (14 000/μL) at enrollment were more likely to discontinue treatment (P < .05). Anti-D was an effective maintenance treatment for two thirds of Rh+, nonsplenectomized adults with ITP who had failed an initial steroid course. Intermittent infusions of intravenous anti-D allowed more than 40% of these adults to avoid splenectomy and to achieve stable platelet counts off all therapy, even after many months of treatment. Platelet count at study entry was the primary predictor of outcome.