Drug-induced Thrombotic Microangiopathy with Concurrent Proteasome Inhibitor Use in the Treatment of Multiple Myeloma: A Case Series and Review of the Literature

Carfilzomib‐Induced Thrombotic Microangiopathy—Two Case Reports

BACKGROUND

Thrombotic microangiopathy (TMA) is a pathological syndrome characterized by a combination of three key features: microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and organ damage, primarily affecting the kidneys. There are several drugs known to have a definite or probable causal association with TMA, and carfilzomib, a second-generation irreversible proteasome inhibitor (PI), approved for the treatment of multiple myeloma (MM), is one of them. In the medical literature, there have been a growing number of reports describing this serious adverse event occurring in MM patients. The precise mechanisms underlying the development of PI-induced TMA are not yet fully understood. Significant improvements in both renal and hematological aspects have been documented following the administration of eculizumab.

RECENT FINDINGS

In this report, we present two cases of MM patients who developed TMA while undergoing carfilzomib therapy. These cases were successfully treated at the Haematology Unit, Careggi Hospital in Florence. In our cases as well, the introduction of eculizumab resulted in rapid enhancements in renal function and platelet count, ultimately leading to the discontinuation of hemodialysis after 4 and 2 weeks, respectively.

DISCUSSION AND CONCLUSION

We assessed 91 patients who received carfilzomib-based therapies at our Haematology Department, during which we identified two cases of DITMA (2.2% incidence). Additionally, we conducted a literature review and discovered a total of 75 documented cases of carfilzomib-induced TMA. Our experience aligns with the cases reported in literature: this adverse event can manifest at any point during treatment, regardless of the specific drug combinations used alongside carfilzomib. The initial and most crucial step in its management involves discontinuing carfilzomib therapy; therefore, recognizing TMA in a timely manner is of utmost importance. Eculizumab could play a role in improving and expediting the resolution of this potentially fatal adverse event, but further studies are needed. In a MM patient receiving carfilzomib, presenting with anemia, thrombocytopenia, and impaired renal function, a carfilzomib-induced TMA should be suspected in order to discontinue the causative agent.

Cardiovascular Toxicity of Proteasome Inhibitors: Underlying Mechanisms and Management Strategies: JACC: CardioOncology State-of-the-Art Review

Proteasome inhibitors (PIs) are the backbone of combination treatments for patients with multiple myeloma and AL amyloidosis, while also indicated in Waldenström's macroglobulinemia and other malignancies. PIs act on proteasome peptidases, causing proteome instability due to accumulating aggregated, unfolded, and/or damaged polypeptides; sustained proteome instability then induces cell cycle arrest and/or apoptosis. Carfilzomib, an intravenous irreversible PI, exhibits a more severe cardiovascular toxicity profile as compared with the orally administered ixazomib or intravenous reversible PI such as bortezomib. Cardiovascular toxicity includes heart failure, hypertension, arrhythmias, and acute coronary syndromes. Because PIs are critical components of the treatment of hematological malignancies and amyloidosis, managing their cardiovascular toxicity involves identifying patients at risk, diagnosing toxicity early at the preclinical level, and offering cardioprotection if needed. Future research is required to elucidate underlying mechanisms, improve risk stratification, define the optimal management strategy, and develop new PIs with safe cardiovascular profiles.

HSPA6 and its role in cancers and other diseases

Heat Shock Protein Family A (Hsp70) Member 6 (HSPA6) (Online Mendelian Inheritance in Man: 140555) belongs to the HSP70 family and is a partially conserved inducible protein in mammals. The HSPA6 gene locates on the human chromosome 1q23.3 and encodes a protein containing two important structural domains: The N-terminal nucleotide-binding domain and the C-terminal substrate-binding domain. Currently, studies have found that HSPA6 not only plays a role in the tumorigenesis and tumor progresses but also causes non-tumor-related diseases. Furthermore, HSPA6 exhibits to inhibit tumorigenesis and tumor progression in some types of cancers but promotes in others. Even though HSPA6 research has increased, its exact roles and mechanisms are still unclear. This article reviews the structure, expression, function, research progress, possible mechanism, and perspective of HSPA6 in cancers and other diseases, highlighting its potential role as a targeted therapeutic and prognostic marker.

Carfilzomib-induced thrombotic microangiopathy is underestimated in clinical practice: A report of five patients and literature review

Carfilzomib (Cfz) is widely used to treat multiple myeloma. However, real-world data of the incidence of thrombotic microangiopathy (TMA) caused by Cfz is inconsistent (<1-5%). We evaluated 96 consecutive patients who received Cfz to evaluate the incidence of TMA in clinical practice. TMA developed in five patients (5.2%) who were mainly receiving high-dose Cfz (≥56 mg/m²). Based on a literature review, precaution should be taken for Cfz-induced TMA in male patients receiving high-dose Cfz irrespective of the combination therapy, Cfz administration period, and complement level. In conclusion, Cfz-induced TMA might be underestimated in clinical practice, and early intervention should be considered.

Carfilzomib-induced atypical haemolytic uraemic syndrome: a diagnostic challenge and therapeutic success

Haemolytic uraemic syndrome (HUS) is a thrombotic microangiopathy (TMA) that presents with renal insufficiency, thrombocytopaenia and microangiopathic haemolytic anaemia. Typical HUS is associated with Shiga toxin while atypical HUS (aHUS) is due to overactivation of the alternative complement pathway. aHUS has numerous causes, including drugs, with rare reports of carfilzomib, a proteasome inhibitor used in multiple myeloma, as causative agent. Cases vary in presentation, presenting a diagnostic challenge. Historically, TMAs were treated with plasma exchange. aHUS, however, is considered refractory to plasma exchange and best treated with eculizumab, a monoclonal antibody targeting C5, a terminal complement protein. We report a patient with history of multiple myeloma who presented with headaches, elevated blood pressure, petechiae, ecchymosis and haemolytic anaemia. His condition was determined to be carfilzomib-induced aHUS and he was successfully treated with eculizumab. Early detection and treatment of drug-induced aHUS is vital in reducing morbidity and mortality related to the condition.