Immune thrombotic thrombocytopenic purpura in older patients: Results from the Spanish TTP Registry (REPTT).

Immune thrombotic thrombocytopenic purpura (iTTP) is an ultra-rare disease that seldom occurs in the elderly. Few reports have studied the clinical course of iTTP in older patients. In this study, we have analysed the clinical characteristics at presentation and response to therapy in a series of 44 patients with iTTP ≥60 years at diagnosis from the Spanish TTP Registry and compared them with 209 patients with <60 years at diagnosis from the same Registry. Similar symptoms and laboratory results were described in both groups, except for a higher incidence of renal dysfunction among older patients (23% vs. 43.1%; p = 0.008). Front-line treatment in patients ≥60 years was like that administered in younger patients. Also, no evidence of a difference in clinical response and overall survival was seen in both groups. Of note, 14 and 25 patients ≥60 years received treatment with caplacizumab and rituximab, respectively, showing a favourable safety and efficacy profile, like that observed in patients <60 years.

Inadequate response to imatinib treatment in chronic myeloid leukemia due to a drug interaction with phenytoin.

Imatinib mesylate and the newer BCR-ABL tyrosine kinase inhibitors are the standard therapy for chronic myeloid leukemia. Although these are remarkably effective drugs, some mechanisms of resistance have been identified including drug-to-drug interactions. Here we present the case of a chronic myeloid leukemia patient with an inadequate response to imatinib due to concurrent phenytoin administration. Conspicuously low imatinib plasma trough levels were documented. Imatinib dose was increased from 400 to 800 mg with good response. In conclusion, drug-to-drug interactions should be ruled out in cases of resistance to tyrosine kinase inhibitor treatment. Potent inducers of cytochrome P450 isoenzyme CYP3A4, as phenytoin, could induce inadequate responses due to increased imatinib clearance and low imatinib trough plasma levels. Thus, this interaction should be avoided. When this is not possible, dose escalation of imatinib and measurement of plasma levels, if available, is recommended.

Eosinophilia secondary to lenalidomide therapy.

WHAT IS KNOWN AND OBJECTIVE: Limited data are available on eosinophilia as a drug adverse event. We describe a case of eosinophilia from lenalidomide therapy. CASE DESCRIPTION: A 50-year-old woman received lenalidomide, dexamethasone and cyclophosphamide as POEMS syndrome treatment. Eosinophil count rose during lenalidomide treatment and decreased in the periods off treatment. Naranjo nomogram suggested a probable association between the use of lenalidomide and eosinophilia. WHAT IS NEW AND CONCLUSION: Eosinophilia has rarely been described with lenalidomide. This case shows a clear temporal relationship between lenalidomide and eosinophilia.