Thrombotic Thrombocytopenic Purpura in Interferon Beta-1a-Treated Patient Diagnosed with Relapsing-Remitting Multiple Sclerosis: A Case Report

Background: Secondary thrombotic thrombocytopenic purpura (TTP) due to interferon beta-1a intramuscular (im) treatment is an uncommon adverse effect with only a few cases in multiple sclerosis patients reported worldwide. TTP together with haemolytic uremic syndrome (HUS) are classic forms of thrombotic microangiopathy, characterized by small-vessel platelet micro-thrombi that manifest clinically in a similar manner. Most common signs and symptoms include bruises and ecchymosis, neurologic symptoms and renal impairment. Interferon beta-1a represents one of the first-line therapies for relapsing-remitting multiple sclerosis due to its accessibility and efficacy. Case presentation: A 36-year-old woman who was previously diagnosed with relapsing-remitting multiple sclerosis had received weekly intramuscular injections with beta-interferon-1a (Avonex 30 mcg). After 9 months of treatment, she presented bruises and ecchymosis on her limbs and torso, epistaxis, gingival bleeding aggravated within 48 h and a persistent headache that was non-responsive to common analgesics. Haematology tests revealed typical results for thrombotic microangiopathy, including severe thrombocytopenia (4000/mm3) and microangiopathic haemolytic anaemia with frequent schistocytes on the peripheral blood smear. Once the beta-interferon administration was ceased and upon the initiation of methylprednisolone, the symptoms remitted. Conclusions: In this case study, we portrayed the particular association between the remission phase of multiple sclerosis and the violent onset of interferon-induced thrombotic thrombocytopenic purpura.

OP130 Economic Evaluation Of High-Cost Drugs For Relapsing-Remitting Multiple Sclerosis In Thailand

IntroductionDrugs for relapsing-remitting multiple sclerosis (RRMS) are costly and not included in the National List of Essential Medicines of Thailand yet. This study aims to conduct an economic evaluation of high-cost drugs for RRMS.MethodsThe Markov model was used to estimate lifetime costs and quality-adjusted life years (QALYs) gained. The treatment options include Interferon beta-1a (IFN) and Teriflunomide (TERI) (first-line), Fingolimod (FIN) and Natalizumab (NATA) (second-line), and Alemtuzumab (ALEM) (third-line) compared with usual care. The effectiveness of drugs was retrieved by network meta-analysis. The probability of health state transition was obtained from primary data. Treatment-related costs were derived from the national database. Other costs and utilities were obtained from the study in Thai RRMS patients.ResultsThe lowest lifetime costs option was usual care (THB2 million) (USD65,808), while the highest QALY gained option was IFN-NATA-ALEM (8.6 QALY gained). All treatment options were not cost-effective compared with usual care at the threshold of THB160,000 (USD5,300) per QALY gained. However, the option of IFN-NATA-ALEM yielded the lowest incremental cost-effectiveness ratio (ICER), which was THB4.4 million (USD144,778) per QALY gained.ConclusionsHigh-cost drugs were not cost-effective; nonetheless, the IFN-NATA-ALEM option could increase QALY gained with the lowest additional budget. The government should negotiate the price of IFN to decrease by eighty percent.