Low dose rituximab has been successful in treating some patients with autoimmune cytopenias. Recently reported data indicate preemptive rituximab may postpone hematologic relapses of TTP in patients with chronic severe ADAMTS13 deficiency.
A now 22-year-old woman had multi-relapsing TTP with five episodes over the previous 10 years, three of which were successfully treated with four doses of rituximab 375 mg/m2. The most recent course in 2009 was given preemptively because intense ADAMTS13 monitoring had shown that previous hematologic relapses followed shortly after developing severe ADAMTS13 deficiency. Asymptomatic chronic IgG deficiency less than 300 mg% had followed this most recent rituximab course given in 2009.
In 2014, continued intense ADAMTS13 monitering disclosed a new progressive decrease in ADAMTS13 levels from normal to severely deficient levels with a weak inhibitor, but no hematologic or clinical changes. Just two 100 mg rituximab doses have been followed by a progressive rise of ADAMTS13 levels to solidly normal values with significant improvement by day 13 post initiation and normalization by day 34.
Low dose rituximab could be a viable alternative for preemptively managing TTP patients with persistently severly low ADAMTS13 levels.
Off Label Use: Off label use of rituximab to treat TTP.
Asterisk with author names denotes non-ASH members.