P0240ACQUIRED THROMBOTIC THROMBOCYTOPENIC PURPURA IN HIV POSITIVE PATIENTS SUCCESSFULLY TREATED WITH CAPLACIZUMAB: ABOUT TWO CASES

Abstract

Abstract Background and Aims Acquired thrombotic thrombocytopenic purpura (aTTP) is a thrombotic microangiopathy still nowadays associated with a high risk of death. Standards of care included at first the association of plasmatic exchanges, Rituximab and steroids. The emergence of Caplacizumab, a nanobody targeting the A1 receptor of Von Willebrand Factor (VWF), significantly changed the prognosis of the disease. Thrombocytopenia is frequent in HIV positive patients, and aTTP is frequently considered. Prevalence of HIV positive in aTTP patients ranges from less than 1% in western countries, up to more than 50% in African countries. The pathophysiology still remains partially understood, leading to the development of autoantibodies targeting the ADAMTS13 metalloprotease. For now, no specific recommendations are available, and standards of care consist in treating HIV positive patient the same as other aTTP patients. We present the first description of two HIV positive patients, successfully treated with caplacizumab. Method We report there two cases of black women, respectively aged 31 (Patient 1) and 52 years old (Patient 2), both positive for HIV for several years. The first one had stopped any antiviral treatment few months ago, and had a positive blood viral load of 110764 copies/ml. Her CD4+ rate was 30/mm3. The second one was under antiviral medication, with a negative viral load and a CD4+ rate of 295/mm3. Both were admitted in our department because of low platelet levels and hemolysis, associated with inflammatory triggers. Bacteriema for Streptococcus mitis was discovered on admission in Patient 1 and Patient 2, who had a long-term follow-up for Still disease, presented with a flare-up. Results Both patients had positive anti-ADAMTS13 autoantibodies (Patient 1: titer 42 UI/ml, Patient 2: 45 UI/ml), with undetectable ADAMTS-13 activities. They were treated with plasmatic exchanges until platelets levels reached over 150 G/L, steroids 1.5 mg/kg/j, Rituximab 375 mg/m2 at day 1, 4 and 8 and finally caplacizumab 10 mg before the 2nd plasmatic exchange and every day until the ADAMTS13 activity reached over 20%. Antiviral therapy and antibiotics were initiated in Patient 1 and antiviral therapy was maintained in Patient 2. The evolution was promptly favorable with normalization of platelets levels at Day 4 in Patient 1, and Day 15 in Patient 2. Patient 1 stopped caplacizumab at Day 12 and Patient 2 at day 17, when ADAMTS 13 reached over 20%. None of them relapsed after treatment, with a respective follow-up of 4 and 2 months. Conclusion Caplacizumab seems to be a safe and efficient treatment for aTTP in HIV positive patients.