Secondary thrombotic microangiopathy in two patients with Philadelphia-positive hematological malignancies treated with imatinib mesylate

Hematological Malignancies and the Kidney

The incidence of hematologic malignancies is on the rise worldwide. Kidney disease is ubiquitous in patients with hematologic malignancies, encompassing a wide spectrum of disorders involving each kidney compartment, including the vasculature, tubules, interstitium, and glomerulus, and there is significant overlap of kidney involvement with each hematologic malignancy. Vascular disorders include both microvascular and macrovascular damage, via thrombotic microangiopathy, hyperleukocytosis, hyperviscosity, and cryoglobulinemia. The tubulointerstitial compartment may be affected by prerenal azotemia and acute tubular injury, but malignant infiltration, tumor lysis syndrome, extramedullary hematopoiesis, cast nephropathy, granulomatous interstitial nephritis, and lysozymuria should be considered in certain populations. Obstructive uropathy may occur due to nephrolithiasis or retroperitoneal fibrosis. Glomerular disorders, including membranoproliferative, membranous, minimal change, and focal segmental glomerulosclerosis, can rarely occur. By understanding how each compartment may be affected, care can best be optimized for these patients. In this review, we summarize the widely varied etiologies of kidney diseases stratified by kidney compartment and hematologic malignancy, focusing on demographics, pathology, pathophysiology, mechanism, and outcomes. We conclude with common electrolyte abnormalities associated with hematologic malignancies.

Focal segmental glomerulosclerosis and concurrent glomerular microangiopathy after long-term imatinib administration

A 79-year-old Japanese man was admitted to our hospital because of proteinuria and kidney dysfunction. He was diagnosed with chronic myeloid leukemia 13 years before and was treated with imatinib. Deep molecular response was achieved but he developed 1+ proteinuria in the first year, which gradually worsened thereafter. Imatinib was discontinued 12 years later but proteinuria and kidney dysfunction were progressive. Percutaneous kidney biopsy revealed mild mesangial hyper-cellularity and matrix increase, swelling of endothelial cells, and partial double contours of glomerular tufts. Subendothelial edema in the interlobular artery was also noted. Immunofluorescence was not remarkable. Electron microscopy revealed endothelial injury with severe sub-endothelial edema. Since imatinib had already been discontinued, conservative therapy with maximal dose of azilsartan was administered. A second biopsy was performed 1 year later because of further deterioration of kidney function, which revealed markedly increased global glomerulosclerosis and severe interstitial fibrosis and tubular atrophy. Segmental glomerulosclerosis with podocyte hyperplasia was also observed. Electron microscopy revealed glomerulosclerotic changes and partially attenuated endothelial injury. Two and a half years later, proteinuria reduced, progression of kidney dysfunction slowed, and he was independent on dialysis therapy. Molecular response of chronic myeloid leukemia was also maintained. The clinical course suggested that endothelial and podocyte injuries were induced by imatinib, and that the nephrotoxic effects lasted for a few years after discontinuation.

Thrombotic microangiopathy in oncology - a review

Thrombotic microangiopathy is a syndrome triggered by a wide spectrum of situations, some of which are specific to the Oncology setting. It is characterized by a Coombs-negative microangiopathic haemolytic anemia, thrombocytopenia and organ injury, with characteristic pathological features, resulting from platelet microvascular occlusion.

TMA is rare and its cancer-related subset even more so. TMA triggered by drugs is the most common within this group, including classic chemotherapy and the latest targeted therapies. The neoplastic disease itself and hematopoietic stem-cell transplantation could also be potential triggers.

Evidence-based medical guidance in the management of cancer-related TMA is scarce and the previous knowledge about primary TMA is valuable to understand the disease mechanisms and the potential treatments.

Given the wide spectrum of potential causes for TMA in cancer patients, the aim of this review is to gather the vast information available. For each entity, pathophysiology, clinical features, therapeutic approaches and prognosis will be covered.

Autoimmune Complications in Hematologic Neoplasms

Autoimmune cytopenias (AICy) and autoimmune diseases (AID) can complicate both lymphoid and myeloid neoplasms, and often represent a diagnostic and therapeutic challenge. While autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) are well known, other rarer AICy (autoimmune neutropenia, aplastic anemia, and pure red cell aplasia) and AID (systemic lupus erythematosus, rheumatoid arthritis, vasculitis, thyroiditis, and others) are poorly recognized. This review analyses the available literature of the last 30 years regarding the occurrence of AICy/AID in different onco-hematologic conditions. The latter include chronic lymphocytic leukemia (CLL), lymphomas, multiple myeloma, myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML), myeloproliferative neoplasms, and acute leukemias. On the whole, AICy are observed in up to 10% of CLL and with higher frequencies in certain subtypes of non-Hodgkin lymphoma, whilst they occur in less than 1% of low-risk MDS and CMML. AID are described in up to 30% of myeloid and lymphoid patients, including immune-mediated hemostatic disorders (acquired hemophilia, thrombotic thrombocytopenic purpura, and anti-phospholipid syndrome) that may be severe and fatal. Additionally, AICy/AID are found in about 10% of patients receiving hematopoietic stem cell transplant or treatment with new checkpoint inhibitors. Besides the diagnostic difficulties, these AICy/AID may complicate the clinical management of already immunocompromised patients.

Molecular Mobility and Stability Studies of Amorphous Imatinib Mesylate

The proposed study examined the characterization and stability of solid-state amorphous imatinib mesylate (IM) after 15 months under controlled relative humidity (60 ± 5%) and temperature (25 ± 2 °C) conditions. After 2 weeks, and 1, 3, 6, and 15 months, the samples were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray powder diffractometry (XRPD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Additionally, the amorphous form of imatinib mesylate was obtained via supercooling of the melt in a DSC apparatus, and aged at various temperatures (3, 15, 25 and 30 °C) and time periods (1–16 h). Glass transition and enthalpy relaxation were used to calculate molecular-relaxation-time parameters. The Kohlrausch–Williams–Watts (KWW) equation was applied to fit the experimental enthalpy-relaxation data. The mean molecular-relaxation-time constant (τ) increased with decreasing ageing temperature. The results showed a high stability of amorphous imatinib mesylate adequate to enable its use in solid dosage form.

Thrombotic microangiopathy in cancer

Thrombotic microangiopathy (TMA) is clinical syndrome based on the presence of thrombocytopenia (platelet count <150 K or a reduction of the platelet count by >30% from baseline) accompanied by fragmentation hemolysis (MAHA) and evidence of organ damage. It can be seen in a variety of disorders including thrombotic thrombocytopenic purpura (TTP), atypical hemolytic uremic syndrome (aHUS), shigatoxin related hemolytic uremic syndrome (STEC-HUS). Cancer itself has long been associated with both macro and microvascular thrombosis. In addition, treatment with chemotherapy as well as hematopoetic stem cell transplantation (HCST) has been associated with atypical hemolytic uremic (aHUS) like syndrome. In this review, I will discuss the pathophysiology of TMA in cancer, chemotherapy associated HUS, and HSCT, well as new therapeutic interventions.