Proteasome inhibitor associated thrombotic microangiopathy

Proteasome inhibitor-associated thrombotic microangiopathy: a real-world retrospective and pharmacovigilance database analysis

OBJECTIVES

Thrombotic microangiopathy (TMA) is associated with carfilzomib, but the potential association between bortezomib or ixazomib exposure and TMA is still unknown. Besides, the knowledge of carfilzomib-induced TMA is based mainly on case reports. We aim to quantify the risk and better characterize the clinical features of proteasome inhibitor (PI)-induced TMA.

METHODS

Data from 2004 to 2023 on TMA events induced by PIs were retrieved from the FDA Adverse Event Reporting System (FAERS) database and conducted disproportionality analyse. Case reports/series from 2004 to 2023 on PI-induced TMA were extracted and analyzed retrospectively.

RESULTS

FAERS pharmacovigilance data identified 225 TMA cases across 213 individuals related to PIs therapy. PIs were significantly associated with TMA (n = 213, ROR 1.71 [1.49-1.96]; EBGM 1.70 [1.52]), and carfilzomib had the greatest proportion (58.7%) and highest positive signal values (n = 125, ROR 17.97 [15.04-21.47]; EBGM 17.49 [15.07]) of TMA. Sixty cases (median age: 63 years) from 35 studies showed evidence of TMA, with 37 (61.7%) were male. The typical initial symptoms were gastrointestinal symptoms (45.3%), fever (24.5%), fatigue/asthenia (20.8%), neurological signs (18.9%), and dyspnea (17.0%). The median time to TMA onset was 8 days. Most patients presented with hemolytic anemia (98.1%), thrombocytopenia (96.6%), and acute kidney injury (96.7%). Cessation of PIs and treatment with plasma exchange therapy (25.0%), hemodialysis (31.7%), and eculizumab (26.7%) were associated with improved hematologic outcomes (96.3%) and renal outcomes (93.3%).

CONCLUSION

This study identified PIs agents with significant reporting associations with TMA. A prompt diagnosis of TMA and supportive treatments are necessary for patients receiving PIs concurrent with anemia, thrombocytopenia, and acute kidney injury.

Post-transplant Thrombotic Microangiopathy

Thrombotic microangiopathy (TMA) is a challenging and serious complication of kidney transplantation that significantly affects graft and patient survival, occurring in 0.8%-15% of transplant recipients. TMA is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ injury due to endothelial damage and microthrombi formation in small vessels. However, clinical features can range from a renal-limited form, diagnosed only on a kidney biopsy, to full-blown systemic manifestations, which include neurologic, gastrointestinal, and cardiovascular injury. TMA can arise because of genetic or acquired defects such as in complement-mediated TMA or can occur in the context of other conditions like infections, autoimmune diseases, or immunosuppressive drugs, where complement activation may also play a role. Recurrent TMA after kidney transplant is almost always complement-mediated, although complement overactivation may also play a role in de novo post-transplant TMAs associated with ischemia-reperfusion injury, immunosuppressive drugs, antibody-mediated rejection, viral infections, and relapse of autoimmune diseases, such as antiphospholipid antibody syndrome. Differentiating between a complement-mediated process and one triggered by other factors is often challenging but critical to minimize allograft damage because the former is nonresponsive to supportive therapy, needs long-term anticomplement therapy, and has a high risk of recurrence. Given the central role of complement and effect of genetic defects on the risk of recurrence in many forms of post-transplant TMA, genetic testing for complement disorders is key for proper diagnosis and management. Given that complement activation may also play a role in a subset of TMAs associated with other conditions, prompt recognition and timely initiation of anticomplement therapy is equally important. In addition, TMA associated with noncomplement genes, often part of a broader syndromic process with distinct clinical features, has also been described. Early identification and treatment are essential to prevent graft failure and other severe complications. This review explores the pathophysiologic mechanisms underlying various post-transplant TMAs.

Carfilzomib-associated thrombotic microangiopathy: clinical features and outcomes

BACKGROUND

Carfilzomib, a new proteasome inhibitor indicated for patients with relapsed/refractory myeloma, has been associated with cases of thrombotic microangiopathy (CFZ-TMA). The role of variants in the complement alternative pathway and therapeutic potential of complement blockade with eculizumab remain to be determined.

METHODS

We report 37 cases of CFZ-TMA recorded in the French reference center for TMA with their clinical characteristics, genetic analysis and outcome according to treatments.

RESULTS

A trigger was identified in more than half of cases, including eight influenza and five severe acute respiratory syndrome coronavirus-2 cases. All patients presented with acute kidney injury (AKI) [KDIGO stage 3 in 31 (84%) patients] while neurological (n = 13, 36%) and cardiac (n = 7, 19%) damage were less frequent. ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type I repeats-13) and complement activity were normal (n = 28 and 18 patients tested) and no pathogenic variant in the alternative complement pathway was found in 7 patients tested. TMA resolved in most (n = 34, 94%) patients but 12 (44%) still displayed stage 3 AKI at discharge. Nineteen (51%) patients were treated with therapeutic plasma exchange, 14 (38%) patients received corticosteroids and 18 (50%) were treated with eculizumab. However, none of these treatments demonstrated a significant impact on outcomes.

CONCLUSION

This study is the largest case series of CFZ-TMA since its approval in 2012. Patients present with severe AKI and experience frequent sequelae. Complement variants and blockade therapy do not seem to play a role in the pathophysiology and prognosis of the disease.

Proteasome inhibitors related thrombotic microangiopathy: a systematic and comprehensive review

Proteasome inhibitors (PIs) are crucial in treating multiple myeloma but carry a risk of thrombotic microangiopathy (TMA), especially with carfilzomib use. This systematic review includes 44 studies with 115 cases of PI-induced TMA, where carfilzomib was implicated in 101 cases. Treatment approaches varied: 28 patients received supportive care, 43 underwent therapeutic plasma exchange (TPE), 9 were treated exclusively with eculizumab (ECU), and 13 received both TPE and ECU. Notably, eculizumab significantly improved outcomes for patients unresponsive to initial TPE, achieving complete remission in seven cases. The need for dialysis emerged as a significant predictor of outcomes, often indicating a poor prognosis. For patients suspected of having PI-TMA, it is advisable to discontinue the offending medication promptly, even without definitive laboratory confirmation. In cases where diagnosis is challenging, kidney biopsy may assist if conditions permit. Comprehensive evaluation of the complement system, including genetic mutations, function, and associated complement inhibitory factor antibodies, should be included in the assessment of PI-TMA. Early administration of eculizumab may be beneficial in cases of suspected complement abnormalities or suboptimal response to initial treatments.

Acute Kidney Injury Associated with Anticancer Therapies: Small Molecules and Targeted Therapies

Molecular targeted therapy has revolutionized cancer treatment by significantly improving patient survival compared with standard conventional chemotherapies. The use of these drugs targets specific molecules or targets, which block growth and spread of cancer cells. Many of these therapies have been approved for use with remarkable success in breast, blood, colorectal, lung, and ovarian cancers. The advantage over conventional chemotherapy is its ability to deliver drugs effectively with high specificity while being less toxic. Although known as "targeted," many of these agents lack specificity and selectivity, and they tend to inhibit multiple targets, including those in the kidneys. The side effects usually arise because of dysregulation of targets of the inhibited molecule in normal tissue. The off-target effects are caused by drug binding to unintended targets. The on-target effects are associated with inhibition toward the pathway reflecting inappropriate inhibition or activation of the intended drug target. Early detection and correct management of kidney toxicities is crucial to preserve kidney functions. The knowledge of these toxicities helps guide optimal and continued utilization of these potent therapies. This review summarizes the different types of molecular targeted therapies used in the treatment of cancer and the incidence, severity, and pattern of nephrotoxicity caused by them, with their plausible mechanism and proposed treatment recommendations.

Carfilzomib-induced thrombotic microangiopathy (TMA) refractory to eculizumab: A case report and literature review

This case report describes the clinical course of a patient with relapsed IgA kappa multiple myeloma with high-risk cytogenetics. Initially treated with daratumumab-bortezomib-lenalidomide-dexamethasone (Dara-VRD) then transitioned to lenalidomide maintenance. However, he experienced a relapse and was treated with carfilzomib-based therapy (CFZ) but developed drug-induced thrombotic microangiopathy (DI-TMA). Despite receiving eculizumab and supportive care, the patient's condition worsened, leading to encephalopathy and refractory gastrointestinal bleeding in the setting of persistent thrombocytopenia. Ultimately, the decision was made to transition to comfort-focused care. DI-TMA has been documented with various proteasome inhibitors such as ixazomib and bortezomib. Additionally, other medications such as cyclosporine, tacrolimus, clopidogrel, ticlopidine, and interferon have been associated with DI-TMA as well (Pisoni et al. (Drug Saf 24:491-501, 2001) [18]). Here we discuss a case of carfilzomib-induced TMA (CFZ-TMA) refractory to eculizumab as well as a review of the published 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.

Serum Free Light Chain Kinetics Is Predictive of Renal Response in Myeloma Patients With Renal Impairment-An ALLG Trial of Carfilzomib-Dexamethasone Therapy in Frontline and Relapse

BACKGROUND AND PURPOSE

Renal impairment (RI) confers adverse prognosis in myeloma; its reversal and avoidance of dialysis are crucial. We investigated whether serum free light chain (SFLC) measurements can predict renal outcome, to enable change in therapy to optimize prognosis and avoid dialysis.

PATIENTS AND METHODS

We investigated 36 myeloma patients (17 newly diagnosed [ND]; 19 relapsed refractory [RR]; with median of 5 prior lines) with eGFR 15-40 ml/min treated with carfilzomib (Cfz)-dexamethasone to determine whether SFLC kinetics can predict renal outcomes, and assess efficacy and tolerability.

RESULTS

The change in involved SFLC at Cycle 2 Day 1 was significantly correlated with renal function; for every one log10 reduction in involved SFLC, eGFR increased by 9.0-15.0 mL/min at cycles 2-4, with SFLC reduction of 54%-78%. At a median follow-up of 30.6 months, renal outcomes were favorable-CRrenal 25%, MRrenal 36%. Disease responses (ND 100%, RR 75%), progression-free survival (ND 32.2 months, RR 11.1 months) and overall survival (ND not reached, RR 42.0 months) were comparable to patients without RI. There was significant toxicity, including Cfz-related cardiac impairment of 20% within a cohort with high co-morbidity, and a high incidence of infections.

CONCLUSION

We propose that one log10 reduction in involved SFLC at Cycle 2 Day 1 is an appropriate target for reducing the risk of dialysis in myeloma patients with RI; below this threshold patients may benefit from a change in therapy. While Cfz-dexamethasone achieved favorable renal and disease outcomes, toxicity can be significant in this vulnerable cohort.

Endothelial injury and dysfunction with emerging immunotherapies in multiple myeloma, the impact of COVID-19, and endothelial protection with a focus on the evolving role of defibrotide

Patients with multiple myeloma (MM) were among the groups impacted more severely by the COVID-19 pandemic, with higher rates of severe disease and COVID-19-related mortality. MM and COVID-19, plus post-acute sequelae of SARS-CoV-2 infection, are associated with endothelial dysfunction and injury, with overlapping inflammatory pathways and coagulopathies. Existing treatment options for MM, notably high-dose therapy with autologous stem cell transplantation and novel chimeric antigen receptor (CAR) T-cell therapies and bispecific T-cell engaging antibodies, are also associated with endothelial cell injury and mechanism-related toxicities. These pathologies include cytokine release syndrome (CRS) and neurotoxicity that may be exacerbated by underlying endotheliopathies. In the context of these overlapping risks, prophylaxis and treatment approaches mitigating the inflammatory and pro-coagulant effects of endothelial injury are important considerations for patient management, including cytokine receptor antagonists, thromboprophylaxis with low-molecular-weight heparin and direct oral anticoagulants, and direct endothelial protection with defibrotide in the appropriate clinical settings.

Clinical features, treatment, and outcomes of patients with carfilzomib induced thrombotic microangiopathy

BACKGROUND

Thrombotic microangiopathy (TMA) is associated with carfilzomib, and knowledge of carfilzomib-induced TMA is based mainly on case reports. This study investigated the clinical characteristics of patients with carfilzomib-induced TMA and provided a reference for the rational use of carfilzomib.

METHODS

Reports of carfilzomib-induced TMA were collected for retrospective analysis by searching the Chinese and English databases from inception to January 31, 2024.

RESULTS

Sixty-six patients were included, with a median age of 63 years (range 39, 85). The median time to onset of TMA was 42 days (range 1, 1825) from initial administration, and the median number of cycles was 3 cycles (range 1, 15). Hemolytic anemia was recorded in 64 patients, with a median of 8.3 g/dL (range 4.6, 13). Sixty-three patients had thrombocytopenia with a median of 18 × 109/L (range 1, 139). The median value of increased LDH was 1192 IU/L (range 141, 5378). ADAMTS13 activity was normal in 41 (62.1 %) of the 42 patients. Mutations were found in 9 (13.6 %) of the 15 patients. Fifty-seven patients achieved a clinical response after discontinuing carfilzomib and receiving therapeutic plasma exchange (53.0 %), eculizumab (24.2 %), or hemodialysis (39.4 %).

CONCLUSION

Carfilzomib-induced TMA is an important adverse event that should be considered in patients receiving carfilzomib for multiple myeloma with anemia, thrombocytopenia, and acute kidney injury. Withdrawal of carfilzomib and treatment with eculizumab have proven successful in some patients.

Navigating the Nexus: Lenalidomide-Associated Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic microangiopathy (TMA) marked by thrombocytopenia, microangiopathic hemolytic anemia, and microvascular thrombosis leading to end-organ damage. While TTP commonly results from hereditary or acquired ADAMTS13 deficiency, its association with lenalidomide is notably rare. The link between lenalidomide and TMA is unclear and requires more studies, given the high mortality risk associated with TTP. The underlying mechanism may involve immunomodulatory effects leading to ADAMTS13 inhibitory antibody formation. Herein, we present a case of a 56-year-old male with a history of multiple myeloma status post autologous stem cell transplant, on lenalidomide maintenance therapy for over five years, who presented with progressive weakness, jaundice, palpitations, and paraesthesia in his extremities. On arrival, the patient was afebrile and was neurologically intact except for the subjective paraesthesia. He was found to have critically low ADAMTS13 activity at <0.03 IU/mL and detectable ADAMTS13 inhibitors, with other findings of TTP, requiring discontinuation of lenalidomide, in addition to receiving treatment for this life-threatening TMA.

Cancer drugs and acute kidney injury: new therapies and new challenges

PURPOSE OF REVIEW

Cancer therapies continue to evolve at a rapid pace and although novel treatments, including immunotherapies and targeted therapies have allowed for substantial improvements in cancer survival, they carry associated risks of acute kidney injury (AKI). We aim to summarize the existing literature on AKI associated with the spectrum of systemic cancer treatments, including conventional chemotherapies, newer immunotherapies, and the growing number of targeted cancer therapies, which may be associated with both AKI and 'pseudo-AKI'.

RECENT FINDINGS

Conventional cytotoxic chemotherapies (e.g. cisplatin and other platinum-based agents, methotrexate, pemetrexed, ifosfamide, etc.) with well recognized nephrotoxicities (predominantly tubulointerstitial injury) remain in widespread use. Immunotherapies (e.g., immune checkpoint inhibitors and CAR-T therapies) may be associated with kidney immune-related adverse events, most often acute interstitial nephritis, and rarely, glomerular disease. Recently, multiple targeted cancer therapies have been associated with reduced renal tubular secretion of creatinine, causing elevations in serum creatinine and apparent 'pseudo-AKI'. To complicate matters further, these agents have had biopsy-proven, 'true' kidney injury attributed to them in numerous case reports.

SUMMARY

Clinicians in nephrology and oncology must be aware of the various potential kidney risks with these agents and recognize those with clinically meaningful impact on both cancer and kidney outcomes.

Frequency and characteristics of chemotherapy-associated thrombotic microangiopathy: Analysis from a large pharmacovigilance database

We used the information component (IC), a disproportionate Bayesian analysis comparing the number of observed versus expected adverse drug reactions, to determine the potential association between anti-neoplastic agents and thrombotic microangiopathy (TMA). The IC025 indicates the lower end of 95% of IC, in which a value >0 suggests a disproportionality signal between the drug of interest and the adverse drug reaction. Carfilzomib had the highest IC025 for TMA among all studied chemotherapies followed by gemcitabine, mitomycin, bevacizumab, and bortezomib.

Canagliflozin mitigates carfilzomib-induced endothelial apoptosis via an AMPK-dependent pathway

Carfilzomib (CFZ) is a proteasome inhibitor approved for relapsed/refractory multiple myeloma (MM) but its clinical use is limited by cardiovascular toxicity. The mechanisms of CFZ-induced cardiovascular toxicity are not fully understood but endothelial dysfunction may be a common denominator. Here, we first characterized the direct toxic effects of CFZ on endothelial cells (HUVECs and EA.hy926 cells) and tested whether SGLT2 inhibitors, known to have cardioprotective effects, can protect against CFZ-induced toxicity. To determine the chemotherapeutic effect of CFZ in the presence of SGLT2 inhibitors, MM and lymphoma cells were treated with CFZ with or without canagliflozin. CFZ decreased cell viability and induced apoptotic cell death in endothelial cells in a concentration-dependent manner. CFZ also upregulated ICAM-1 and VCAM-1 and downregulated VEGFR-2. These effects were associated with the activation of Akt and MAPK pathways, inhibition of p70s6k, and downregulation of AMPK. Canagliflozin, but not empagliflozin or dapagliflozin, protected endothelial cells from CFZ-induced apoptosis. Mechanistically, canagliflozin abrogated CFZ-induced JNK activation and AMPK inhibition. AICAR (an AMPK activator) protected from CFZ-induced apoptosis, and compound C (an AMPK inhibitor) abrogated the protective effect of canagliflozin, strongly suggesting that AMPK mediates these effects. Canagliflozin did not interfere with the anticancer effect of CFZ in cancer cells. In conclusion, our findings demonstrate for the first time the direct toxic effects of CFZ in endothelial cells and the associated signaling changes. Canagliflozin abrogated the apoptotic effects of CFZ in endothelial cells in an AMPK-dependent mechanism, without interfering with its cytotoxicity in cancer cells.

Carfilzomib-induced Thrombotic Microangiopathy: A Case Based Review

Carfilzomib is an irreversible proteasome inhibitor currently approved for the treatment of relapsed multiple myeloma. It has been implicated as a cause of thrombotic microangiopathy (TMA) in several case reports. The incidence, risk factors, and treatment of carfilzomib-related TMA remain unclear. Here we describe the clinical presentation and outcome of a 58-year-old man with biopsy-proven TMA that occurred following treatment with carfilzomib-based therapy. We also reviewed the published literature with regard to the incidence, risk factors, treatment options, and outcome of carfilzomib-related TMA.

Eculizumab in the management of drug-induced thrombotic microangiopathy: A scoping review of the literature

Drug-induced TMA (DI-TMA) is a thrombotic microangiopathy (TMA) caused by certain drugs, usually managed by drug discontinuation and supportive measures. Data on the use of complement-inhibition with eculizumab in DI-TMA is scarce, and its benefit in cases of severe or refractory DI-TMA is unclear. We conducted a comprehensive search in PubMed, Embase and MEDLINE databases (2007-2021). We included articles that reported on DI-TMA patients treated with eculizumab and its clinical outcomes. All other causes of TMA were excluded. We evaluated the outcomes of hematologic recovery, renal recovery, and a composite of both (complete TMA recovery). 35 studies fulfilled our search criteria, which included 69 individual cases of DI-TMA treated with eculizumab. Most cases were secondary to chemotherapeutic agents, and the most implicated drugs were gemcitabine (42/69), carfilzomib (11/69), and bevacizumab (5/69). The median number of eculizumab doses given was 6 (range 1-16). 55/69 (80 %) patients achieved renal recovery, after 28-35 days (5-6 doses). 13/22 (59 %) patients were able to discontinue hemodialysis. 50/68 (74 %) patients achieved complete hematologic recovery after 7-14 days (1-2 doses). 41/68 (60 %) patients met criteria for complete TMA recovery. Eculizumab was safely tolerated in all cases, and appeared to be effective in achieving both hematologic and renal recovery in DI-TMA refractory to drug discontinuation and supportive measures, or with severe manifestations associated with significant morbidity or mortality. Our findings suggest that eculizumab may be considered as a potential treatment for severe or refractory DI-TMA that does not improve after initial management, although larger studies are needed.

Multiple myeloma with acute light chain cast nephropathy

Light chain cast nephropathy (LCCN) is a leading cause of acute kidney injury (AKI) in patients with multiple myeloma (MM) and is now defined as a myeloma defining event. While the long-term prognosis has improved with novel agents, short-term mortality remains significantly higher in patients with LCCN especially if the renal failure is not reversed. Recovery of renal function requires a rapid and significant reduction of the involved serum free light chain. Therefore, proper treatment of these patients is of the utmost importance. In this paper, we provide an algorithm for treatment of MM patients who present with biopsy-proven LCCN or in those where other causes of AKI have been ruled out. The algorithm is based on data from randomized trial whenever possible. When trial data is not available, our recommendations is based on non-randomized data and expert opinions on best practices. We recommend that all patients should enroll in a clinical trial if available prior to resorting to the treatment algorithm we outlined.

Mutations in the alternative complement pathway in multiple myeloma patients with carfilzomib-induced thrombotic microangiopathy

Thrombotic microangiopathy (TMA) has been reported to occur in multiple myeloma (MM) patients in association with treatment with carfilzomib, an irreversible proteasome inhibitor (PI). The hallmark of TMA is vascular endothelial damage leading to microangiopathic hemolytic anemia, platelet consumption, fibrin deposition and small-vessel thrombosis with resultant tissue ischemia. The molecular mechanisms underlying carfilzomib-associated TMA are not known. Germline mutations in the complement alternative pathway have been recently shown to portend increased risk for the development of atypical hemolytic uremic syndrome (aHUS) and TMA in the setting of allogeneic stem cell transplant in pediatric patients. We hypothesized that germline mutations in the complement alternative pathway may similarly predispose MM patients to carfilzomib-associated TMA. We identified 10 MM patients with a clinical diagnosis of TMA in the context of carfilzomib treatment and assessed for the presence of germline mutations in the complement alternative pathway. Ten, matched MM patients exposed to carfilzomib but without clinical TMA were used as negative controls. We identified a frequency of deletions in the complement Factor H genes 3 and 1 (delCFHR3-CFHR1) and genes 1 and 4 (delCFHR1-CFHR4) in MM patients with carfilzomib-associated TMA that was higher as compared to the general population and matched controls. Our data suggest that complement alternative pathway dysregulation may confer susceptibility to vascular endothelial injury in MM patients and predispose to development of carfilzomib-associated TMA. Larger, retrospective studies are needed to evaluate whether screening for complement mutations may be indicated to properly counsel patients about TMA risk with carfilzomib use.

Approaches to early diagnosis and prevention of cardiovascular toxicity induced by targeted drugs and immune checkpoint inhibitors in oncohematology: a literature review

The development of targeted drugs and immune checkpoint inhibitors (ICIs), as well as their implementation into clinical practice has allowed increasing the overall and event-free survival of oncohematological patients. Currently, assessment of the efficacy of a therapeutic strategy in each specific case includes the evaluation of an acceptable tolerability profile. The subject of discussion includes cardiovascular complications induced by target drugs and ICIs. The review mainly presents the issues of cardiovascular toxicity (CVT) in certain groups of oncohematological patients (with chronic lymphocytic leukemia, chronic myeloid leukemia, multiple myeloma). The spectrum of cardiovascular adverse effects associated with targeted and ICI therapy in oncohematological practice is quite wide — coronary artery disease, peripheral arterial disease, myocarditis, heart failure, arrhythmias, hypertension. The high importance of the problem of using targeted and immunosuppressive therapy dictates the need to predict adverse effects. The diagnosis of heart failure (one of CVT manifestations) is based on determining the decreased left ventricular ejection fraction during echocardiography, less often — during cardiac magnetic resonance imaging; global longitudinal myocardial strain is a significant parameter of preclinical heart failure, which is determined using the speckle tracking technique. To determine vascular toxicity, a special attention is paid to the vascular wall structure and microcirculation parameters — capillary density at rest, percentage of capillary recovery and perfused capillaries, stiffness index for large blood vessels, reflection index for small arteries, laboratory markers of inflammation and endothelial dysfunction (C-reactive protein, fibrinogen, homocysteine, endothelin 1, vascular endothelial growth factor). CVT prevention presumes the determination of the risk group, correction of risk factors, and administration of protective therapy to very high and high-risk patients. One of the promising directions for preventing vascular toxicity is the use of sodium-glucose linked transporter-2 inhibitors.

[What a cardiologist needs to know about managing a patient with multiple myeloma]

Multiple myeloma is one of the most frequent hematological malignancies in the elderly and corresponds to the presence of a plasma cell clone. Antitumor treatment combines different therapeutics, including alkylating agents, high-dose corticosteroids, immunomodulators and proteasome inhibitors. These treatments can have cardiovascular side effects that are important to be aware of. The role of the cardiologist is essential in preventing, detecting and managing these effects properly in order to improve the cardiological and oncological prognosis of patients.

Carfilzomib's Real-World Safety Outcomes in Korea: Target Trial Emulation Study Using Electronic Health Records

Carfilzomib is a promising anticancer drug for relapsed/refractory multiple myeloma (RRMM). However, real-world evidence has only investigated the cardiovascular safety of carfilzomib, and there is a high demand for thorough safety evaluations. We aimed to comprehensively evaluate the risk of adverse events associated with carfilzomib in Korean patients with RRMM. We followed up with 138 matched patients with RRMM (69 KRd (carfilzomib, lenalidomide, and dexamethasone) and 69 Rd (lenalidomide and dexamethasone) users). A total of 12 adverse events were evaluated. More than 75% of adverse events occurred during the early cycle (1-6 cycles), and the incidence rate showed a tendency to decrease in the later cycle (7-12 and 13-18 cycles). Severities of most adverse events were evaluated as grade 1-2. The KRd regimen were related with significantly increased risks of dyspnea (adjusted HR (aHR) 2.27, 95% confidence interval (CI) 1.24-4.16), muscle spasm (aHR 5.12, 95% CI 1.05-24.9) and thrombocytopenia (aHR 1.84, 95% CI 1.10-3.06). Although the severities were low, carfilzomib has many side effects in treating RRMM; hence, findings on the patterns of its adverse events could lead to both effective and safe use of KRd therapy in real-world settings.

Complement Activation and Thrombotic Microangiopathy Associated With Monoclonal Gammopathy: A National French Case Series

RATIONALE & OBJECTIVE

Hemolytic uremic syndrome (HUS), a thrombotic microangiopathy (TMA) with kidney involvement, is a rare condition in patients with monoclonal gammopathy. In the absence of known causes of TMA, the role of complement activation in endothelial injury in patients with monoclonal gammopathy remains unknown and was the focus of this investigation.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

We studied the 24 patients in the French national registry of HUS between 2000 and 2020 who had monoclonal gammopathy without other causes of secondary TMA. We provide the clinical histories and complement studies of these patients.

FINDINGS

Monoclonal gammopathy-associated TMA with kidney involvement is estimated to be 10 times less frequent than adult atypical HUS (aHUS) in the French national registry. It is characterized by severe clinical features, with 17 of 24 patients requiring dialysis at disease onset, and with median renal survival of only 20 months. TMA-mediated extrarenal manifestations, particularly cutaneous and neurological involvement, were common and associated with poor overall prognosis. Complement studies identified low C3, normal C4, and high soluble C5b-9 levels in 33%, 100%, and 77% of tested patients, respectively, indicating a contribution of the alternative and terminal complement pathways in the pathophysiology of the disease. Genetic abnormalities in complement genes known to be associated with aHUS were found in only 3 of 17 (17%) who were tested.

LIMITATIONS

Retrospective study without comparison group; limited number of patients, limited available blood samples.

CONCLUSIONS

Within the spectrum of TMA, TMA associated with monoclonal gammopathy represents a distinct subset. Our findings suggest that HUS associated with monoclonal immunoglobulin is a complement-mediated disease akin to aHUS.

Acute Kidney Injury in Critically Ill Patients with Cancer

Advances in cancer therapy have significantly improved overall patient survival; however, AKI remains a common complication in patients with cancer, occurring in anywhere from 11% to 22% of patients, depending on patient-related or cancer-specific factors. Critically ill patients with cancer as well as patients with certain malignancies (e.g., leukemias, lymphomas, multiple myeloma, and renal cell carcinoma) are at highest risk of developing AKI. AKI may be a consequence of the underlying malignancy itself or from the wide array of therapies used to treat it. Cancer-associated AKI can affect virtually every compartment of the nephron and can present as subclinical AKI or as overt acute tubular injury, tubulointerstitial nephritis, or thrombotic microangiopathy, among others. AKI can have major repercussions for patients with cancer, potentially jeopardizing further eligibility for therapy and leading to greater morbidity and mortality. This review highlights the epidemiology of AKI in critically ill patients with cancer, risk factors for AKI, and common pathologies associated with certain cancer therapies, as well as the management of AKI in different clinical scenarios. It highlights gaps in our knowledge of AKI in patients with cancer, including the lack of validated biomarkers, as well as evidence-based therapies to prevent AKI and its deleterious consequences.

Influenza-induced thrombotic microangiopathy in a patient with cancer on proteasome inhibitor: a diagnostic dilemma

Thrombotic microangiopathy (TMA) in a cancer patient is a common complication of either cancer itself or anticancer therapy. Incidence of TMA from anticancer therapy was found to be > 15%, since the introduction of anti-angiogenic drugs like anti-vascular endothelial growth factor agents. It is, however, important to not ignore other causes of TMA such as bacteria, viruses, antiplatelet drugs, hereditary complement mutations, and autoimmune disorders. We present such a diagnostic dilemma in our patient who was admitted with influenza and was found to have TMA on renal biopsy, while on proteasome inhibitor (PI) therapy. With this case, we would like to highlight the importance of understanding the true cause of TMA to avoid unwarranted long-term discontinuation of life saving anti-cancer drugs after TMA resolution.

Genetic and Functional Evidence of Complement Dysregulation in Multiple Myeloma Patients with Carfilzomib-Induced Thrombotic Microangiopathy Compared to Controls

BACKGROUND

Carfilzomib, an irreversible proteasome inhibitor approved for the treatment of relapsed/refractory Multiple Myeloma (MM) has been associated with Thrombotic Microangiopathy (TMA). Several pathogenetic mechanisms of carfilzomib-induced TMA have been proposed; however, recently, there has been a shift of focus on the potential contribution of complement dysregulation. Our aim was to explore whether patients with carfilzomib-induced TMA harbor germline variants of complement-related genes, which have been characterized as risk factors for TMA.

METHODS

We retrospectively recruited consecutive MM patients with carfilzomib-induced TMA and compared them to MM patients who received ≥4 cycles of carfilzomib and did not develop signs/symptoms of TMA, in a 1:2 ratio. Genomic DNA from peripheral blood was analyzed using next generation sequencing (NGS) with a complement-related gene panel; ADAMTS13 activity and soluble C5b-9 were measured using ELISA.

RESULTS

Complement-related variants were more common in patients with carfilzomib-induced TMA compared to non-TMA controls, regardless of patient and treatment characteristics; ADAMTS13 activity and C5b-9 were compatible with the phenotype of complement-related TMA.

CONCLUSIONS

We confirmed the previous findings that implicated complement-related genes in the pathogenesis of carfilzomib-induced TMA. Most importantly, by incorporating a control group of non-TMA MM patients treated with carfilzomib-based regimens and functional complement assays, we enhanced the credibility of our findings.

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.

Unique Presentation of Bortezomib-Associated Thrombotic Microangiopathy Responsive to Therapeutic Plasma Exchange and Eculizumab Therapy

Thrombotic microangiopathies (TMA) are a rare group of life-threatening hematological conditions characterized by thrombocytopenia and microangiopathic hemolytic anemia. Although our understanding of the pathophysiology and the availability of diagnostic testing has improved for primary TMAs, such as thrombotic thrombocytopenic purpura, the pathophysiology underlying secondary TMAs, including drug-induced TMAs (DITMAs), remains less clear. In this case report, we present the unique case of a patient with a history of multiple myeloma that presented four months after the initiation of bortezomib therapy with a bortezomib-associated TMA that responded to therapeutic plasma exchange (TPE) with plasma replacement and eculizumab therapy. This case demonstrates the possible utility of TPE with plasma replacement and eculizumab therapy in DITMA patients that fail to respond following a trial of holding the suspected medication.

Practical guidance for new multiple myeloma treatment regimens: A nursing perspective

As is the case for solid tumors, treatment paradigms have shifted from non-specific chemotherapeutic agents towards novel targeted drugs in the treatment of patients with multiple myeloma (MM). Currently, multiple targeted therapies are available to treat patients augmenting the arsenal of modalities which also includes chemotherapy, immunotherapy, radiation therapy, hematopoietic stem cell transplantation (HSCST) and chimeric antigen T-cell therapy (CAR-T). These novel, targeted agents have dramatically increased optimism for patients, who may now be treated over many years with successive regimens. As fortunate as we are to have these new therapies available for our patients, this advantage is juxtaposed with the challenges involved with delivering them safely. While each class of agents has demonstrated efficacy, in terms of response rates and survival, they also exert class effects which pose risks for toxicity. In addition, newer generation agents within the classes often have slightly different toxicity profiles than did their predecessors. These factors must be addressed, and their risks mitigated by the multidisciplinary team. This review presents a summary of the evolution of drug development for MM. For each targeted agent, the efficacy data from pivotal trials and highlights of the risks that were demonstrated in trials, as well as during post-marketing surveillance, are presented. Specific risks associated with agents within the classes, that are not shared with all new class members, are described. A table presenting these potential risks, with recommended nursing actions to mitigate toxicity, is provided as a quick reference that nurses may use during the planning, and provision, of patient care.

Carfilzomib-induced thrombotic microangiopathy. A case report

INTRODUCTION

Drug-induced thrombotic microangiopathy (DITMA) is an acquired condition resulting from exposure to a drug that induces the formation of platelet-rich thrombi in small arterioles or capillaries secondary to drug-dependent antibodies or direct tissue toxicity. Carfilzomib is a selective proteasome inhibitor approved to treat selected patients with Multiple Myeloma (MM). It is one of the drugs with the strongest evidence for a causal association with non-antibody-mediated DITMA.

CASE REPORT

A 75-year-old man presented to the emergency department for the outbreak of vomit, asthenia, oliguria and dark stool emission. He was recently diagnosed with multiple myeloma, treated with lenalidomide, dexamethasone and carfilzomib. Laboratory exams were significant for microangiopathic haemolytic anaemia, thrombocytopenia and new-onset renal failure. ADAMTS-13 levels were in range, and no infectious signs were found both in blood nor in stool test.

MANAGEMENT & OUTCOME

A carfilzomib induced thrombotic microangiopathy was soon suspected. Thus, since daily haemodialysis and supportive care did not seem to get a fast enough recovery, the patient was treated with eculizumab with a good general outcome.

DISCUSSION

Drug-induced thrombotic microangiopathy is a rare and often life-threatening acquired condition whose diagnosis can be challenging and whose therapy is not always limited to supportive treatment and drug avoidance. Carfilzomib, along with other proteasome inhibitors, is one of the described potential drugs which can trigger such a manifestation.

Current trends of anti-cancer molecular targeted therapies: a narrative review focusing on renal complications and their histological features

Among the recent advancements in cancer treatment, the emergence of novel drugs targeting a specific molecule has considerably modulated the therapeutic strategies. Despite the efficacy, the associated renal complications distinct from conventional chemotherapeutic drugs have been reported. Targeted therapy drugs include monoclonal antibodies and small molecule agents. Bevacizumab is one of the monoclonal antibodies that targets vascular endothelial growth factor (VEGF) and blocks tumor angiogenesis. This anti-angiogenic effect causes endothelial injury, resulting in "thrombotic microangiopathy-like lesion" confined to the glomerulus. Segmental hyalinosis of the glomerular tuft is also observed. The small molecular agents, including tyrosine kinase inhibitors (TKIs), such as pazopanib, can cause endothelial injury and podocytopathy through blocking VEGF receptors and their downstream signaling. Minimal change nephrotic syndrome and focal segmental glomerulosclerosis are associated with TKIs-induced renal complications. Immune checkpoint inhibitors (ICIs), such as PD-1, CTLA-4 and PD-L1, are a novel form of immunotherapy against cancer, which modulates immune checkpoints. Owing to its unique function, ICIs cause inflammatory side effects referred to as immune-related adverse events (irAEs). irAEs in the kidney commonly include acute tubulointerstitial nephritis and tubulitis, occasionally accompanied by granuloma formation. The occurrence of vasculitis, thrombotic microangiopathy, and glomerulonephritis is also reported. Renal toxicity associated with other molecular drugs such as protease inhibitors and mammalian target of rapamycin inhibitors has also been documented. In this article, we review the clinico-histopathological aspects of renal complications associated with molecular targeted therapies, focusing on anti-VEGF agents and immune checkpoint inhibitors from the pathologists' viewpoint.

The Proteasome Inhibitor Bortezomib Induces Apoptosis and Activation in Gel-Filtered Human Platelets

Bortezomib (BTZ) has demonstrated its efficacy in several hematological disorders and has been associated with thrombocytopenia. There is controversy about the effect of BTZ on human platelets, so we set out to determine its effect on various types of platelet samples. Human platelets were investigated in platelet-rich plasma (PRP) and as gel-filtered platelets (GFPs). Mitochondrial inner membrane potential depolarization and phosphatidylserine (PS) and P-selectin expression levels were studied by flow cytometry, while thrombin generation was measured by a fluorescent method. In PRP, BTZ caused negligible PS expression after 60 min of treatment. However, in GFPs, PS expression was dose- and time-dependently increased in the BTZ-treated groups, as was P-selectin. The percentage of depolarized cells was also higher after BTZ pretreatment at both time points. Peak thrombin and velocity index increased significantly even with the lowest BTZ concentration (p = 0.0019; p = 0.0032) whereas time to peak and start tail parameters decreased (p = 0.0007; p = 0.0034). The difference between PRP and GFP results can be attributed to the presence of plasma proteins in PRP, as the PS-stimulating effect of BTZ could be attenuated by supplementing GFPs with purified human albumin. Overall, BTZ induces a procoagulant platelet phenotype in an experimental setting devoid of plasma proteins.

How I treat microangiopathic hemolytic anemia in patients with cancer

Microangiopathic hemolytic anemia (MAHA) with thrombocytopenia, suggests a thrombotic microangiopathy (TMA), linked with thrombus formation affecting small or larger vessels. In cancer patients, it may be directly related to the underlying malignancy (initial presentation or progressive disease), to its treatment, or a separate incidental diagnosis. It is vital to differentiate incidental thrombotic thrombocytopenia purpura or atypical hemolytic uremic syndrome in cancer patients presenting with a TMA, as they have different treatment strategies, and prompt initiation of treatment impacts outcome. In the oncology patient, widespread microvascular metastases or extensive bone marrow involvement can cause MAHA and thrombocytopenia. A disseminated intravascular coagulation (DIC) picture may be precipitated by sepsis or driven by the cancer itself. Cancer therapies may cause a TMA, either dose-dependent toxicity, or an idiosyncratic immune-mediated reaction due to drug-dependent antibodies. Many causes of TMA seen in the oncology patient do not respond to plasma exchange and, where feasible, treatment of the underlying malignancy is important in controlling both cancer-TMA or DIC driven disease. Drug-induced TMA should be considered and any putative causal agent stopped. We will discuss the differential diagnosis and treatment of MAHA in patients with cancer using clinical cases to highlight management principles.

The Link Between Conventional and Novel Anti-Cancer Therapeutics with Thrombotic Microangiopathy

BACKGROUND

Kidney disease associated with cancer and anti-cancer therapies has been increasingly recognized in the field of onco-nephrology. In particular, drug-induced nephrotoxicity has important implications since most chemotherapeutic agents have a nephrotoxic potential. Also, standard creatinine clearance methods used for the measurement of kidney function have been questioned in cancer patients due to factors like low muscle mass and poor nutritional status. Overestimations of the glomerular filtration rate, not only can increase the nephrotoxic potential of different agents, but also further limit the use of first-line therapies.

OBJECTIVE

This review covers specifically the drug-induced thrombotic microangiopathy and its two pathophysiologic mechanisms which include immune or idiosyncratic reactions, and non-immune or dose-dependent ones.

CONCLUSION

As novel cancer therapies are developed, it is paramount to pursue a better understanding of conventional and novel chemotherapeutic agents and their role in kidney disease.

The Syndromes of Thrombotic Microangiopathy: A Critical Appraisal on Complement Dysregulation

Thrombotic microangiopathy (TMA) is a rare and potentially life-threatening condition that can be caused by a heterogeneous group of diseases, often affecting the brain and kidneys. TMAs should be classified according to etiology to indicate targets for treatment. Complement dysregulation is an important cause of TMA that defines cases not related to coexisting conditions, that is, primary atypical hemolytic uremic syndrome (HUS). Ever since the approval of therapeutic complement inhibition, the approach of TMA has focused on the recognition of primary atypical HUS. Recent advances, however, demonstrated the pivotal role of complement dysregulation in specific subtypes of patients considered to have secondary atypical HUS. This is particularly the case in patients presenting with coexisting hypertensive emergency, pregnancy, and kidney transplantation, shifting the paradigm of disease. In contrast, complement dysregulation is uncommon in patients with other coexisting conditions, such as bacterial infection, drug use, cancer, and autoimmunity, among other disorders. In this review, we performed a critical appraisal on complement dysregulation and the use of therapeutic complement inhibition in TMAs associated with coexisting conditions and outline a pragmatic approach to diagnosis and treatment. For future studies, we advocate the term complement-mediated TMA as opposed to the traditional atypical HUS-type classification.

The role of carfilzomib in relapsed/refractory multiple myeloma

Carfilzomib is the second proteasome inhibitor approved for relapsed multiple myeloma. Since its approval in 2012, carfilzomib has been an active and versatile drug, based on its efficacy as a single agent; superiority as a doublet with dexamethasone compared with bortezomib and dexamethasone; and as a partner in diverse three drug combinations such as with lenalidomide or daratumumab. While it has an established place in relapsed disease, clinicians should be aware of its cardiovascular and renal adverse event profile, which is manageable, in order to optimize outcomes. This review will provide a perspective on the current and future role of carfilzomib in relapsed/refractory multiple myeloma.

Thrombotic microangiopathy in untreated myeloma patients receiving carfilzomib, cyclophosphamide and dexamethasone on the CARDAMON study

Proteasome inhibitors have been associated with thrombotic microangiopathy (TMA) - a group of disorders characterised by occlusive microvascular thrombosis causing microangiopathic haemolytic anaemia, thrombocytopenia and end-organ damage. To date, carfilzomib-associated TMA has predominantly been described in relapsed/refractory myeloma patients. We report eight patients with newly diagnosed myeloma who experienced TMA events while receiving carfilzomib on the phase II CARDAMON trial. The first three occurred during maintenance single-agent carfilzomib, two occurred at induction with carfilzomib given with cyclophosphamide and dexamethasone (KCd) and three occurred during KCd consolidation. At TMA presentation 6/8 were hypertensive; 7/8 had acute kidney injury and in three, renal impairment persisted after resolution of TMA in other respects. The mechanism of carfilzomib-associated TMA remains unclear, though patients with known hypertension seem particularly susceptible. Given the first three cases occurred during maintenance after a longer than five-week treatment break, a protocol amendment was instituted with: aggressive hypertension management, carfilzomib step-up dosing (20 mg/m2 on day 1) at start of maintenance before dose escalation to 56 mg/m2 maximum, and adding 10 mg dexamethasone as premedication to maintenance carfilzomib infusions. No further TMA events occurred during maintenance following this amendment and the TMA incidence reduced from 4·2 to 1·6 per 1 000 patient cycles.

Bortezomib-induced glomerular microangiopathy complicated with monoclonal immunoglobulin deposition disease

A 75-year-old man admitted with IgG λ-type myeloma with creatinine level of 2.3 mg/dL. Serum lactate dehydrogenase level and platelet count were normal. Urinalysis demonstrated massive proteinuria dominated by albuminuria. Weekly bortezomib and dexamethasone therapy were started to treat myeloma but failed to be continued because of rapid deterioration of renal function and increase in proteinuria 1 week after the treatment. His renal function exacerbated to require hemodialysis for a month. There was no clinical evidence of tumor lysis syndrome or thrombocytopenia throughout the course of his acute kidney injury (AKI). After he became dialysis independent, a renal biopsy was performed to clarify myeloma-related renal involvement and the cause of AKI. As a result, IgG2-λ monoclonal immunoglobulin deposition disease (MIDD) and severe endothelial injury were revealed. There was no evidence of cast nephropathy. Bortezomib-induced glomerular microangiopathy (GMA) superimposed on MIDD. Bortezomib has a potential risk to cause drug-induced GMA without systemic thrombotic microangiopathy, in which vascular endothelial growth factor-nuclear factor-κ B pathway could be involved. This is the first case of biopsy-proven bortezomib-induced GMA. If proteinuria (mainly albuminuria) increases after using bortezomib, GMA should be suspected as an adverse effect of bortezomib even absent of clinical signs of systemic thrombotic microangiopathy.

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.

The Role of the Proteasome in Platelet Function

Platelets are megakaryocyte-derived acellular fragments prepped to maintain primary hemostasis and thrombosis by preserving vascular integrity. Although they lack nuclei, platelets harbor functional genomic mediators that bolster platelet activity in a signal-specific manner by performing limited de novo protein synthesis. Furthermore, despite their limited protein synthesis, platelets are equipped with multiple protein degradation mechanisms, such as the proteasome. In nucleated cells, the functions of the proteasome are well established and primarily include proteostasis among a myriad of other signaling processes. However, the role of proteasome-mediated protein degradation in platelets remains elusive. In this review article, we recapitulate the developing literature on the functions of the proteasome in platelets, discussing its emerging regulatory role in platelet viability and function and highlighting how its functional coupling with the transcription factor NF-κB constitutes a novel potential therapeutic target in atherothrombotic diseases.

Kidney injury and disease in patients with haematological malignancies

Acute kidney injury (AKI) is common in patients with cancer, especially in those with haematological malignancies. Kidney injury might be a direct consequence of the underlying haematological condition. For example, in the case of lymphoma infiltration or extramedullary haematopoiesis, it might be caused by a tumour product; in the case of cast nephropathy it might be due to the presence of monoclonal immunoglobulin; or it might result from tumour complications, such as hypercalcaemia. Kidney injury might also be caused by cancer treatment, as many chemotherapeutic agents are nephrotoxic. High-intensity treatments, such as high-dose chemotherapy followed by haematopoietic stem cell transplantation, not only increase the risk of infection but can also cause AKI through various mechanisms, including viral nephropathies, engraftment syndrome and sinusoidal obstruction syndrome. Some conditions, such as thrombotic microangiopathy, might also result directly from the haematological condition or the treatment. Novel immunotherapies, such as immune checkpoint inhibitors and chimeric antigen receptor T cell therapy, can also be nephrotoxic. As new therapies for haematological malignancies with increased anti-tumour efficacy and reduced toxicity are developed, the number of patients receiving these treatments will increase. Clinicians must gain a good understanding of the different mechanisms of kidney injury associated with cancer to better care for these patients.

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.

Carfilzomib-induced endothelial dysfunction, recovery of proteasome activity, and prediction of cardiovascular complications: a prospective study

Carfilzomib (CFZ) improves survival in relapsed/refractory multiple myeloma but is associated with cardiovascular adverse events (CVAEs). We prospectively investigated the effect of CFZ on endothelial function and associations with CVAEs. Forty-eight patients treated with Kd (CFZ 20/56 mg/m² and dexamethasone) underwent serial endothelial function evaluation, using brachial artery flow-mediated dilatation (FMD) and 26S proteasome activity (PrA) measurement in PBMCs; patients were followed until disease progression or cycle 6 for a median of 10 months. FMD and PrA decreased acutely after the first dose (p < 0.01) and FMD decreased at cycles 3 and 6 compared to baseline (p ≤ 0.05). FMD changes were associated with CFZ-induced PrA changes (p < 0.05) and lower PrA recovery during first cycle was associated with more prominent FMD decrease (p = 0.034 for group interaction). During treatment, 25 patients developed Grade ≥3 CVAEs. Low baseline FMD (HR 2.57 lowest vs. higher tertiles, 95% CI 1.081-6.1) was an independent predictor of CVAEs. During treatment, an acute FMD decrease >40% at the end of first cycle was also independently associated with CVAEs (HR = 3.91, 95% CI 1.29-11.83). Kd treatment impairs endothelial function which is associated with PrA inhibition and recovery. Both pre- and posttreatment FMD predicted CFZ-related CVAEs supporting its role as a possible cardiovascular toxicity biomarker.

Two cases of carfilzomib-induced thrombotic microangiopathy successfully treated with Eculizumab in multiple myeloma

BACKGROUND

Treatment with proteasome inhibitors like carfilzomib in patients with multiple myeloma (MM) can induce thrombotic microangiopathy (TMA) characterized by neurological symptoms, acute kidney injury, hemolysis and thrombocytopenia. Successful treatment with the monoclonal antibody eculizumab was described for these patients, but reports of ideal management and definitive treatment protocols are lacking.

CASE PRESENTATION

The first case describes a 43-years-old IgG-kappa-MM patient that developed TMA during the first course of carfilzomib-lenalidomide-dexamethasone (KRd) consolidation after autologous stem cell transplantation (ASCT). In the second case, a 59-years-old IgG-kappa-MM patient showed late-onset TMA during the fourth and last cycle of elotuzumab-KRd consolidation within the DSMM XVII study of the German study group MM (DSMM; clinicalTrials.gov Identifier: NCT03948035). Concurrently, he suffered from influenza A/B infection. Both patients had a high TMA-index for a poor prognosis of TMA. Therapeutically, in both patients plasma exchange (TPE) was initiated as soon as TMA was diagnosed. In patient #1, dialysis became necessary. For both patients, only when the complement inhibitor eculizumab was administered, kidney function and blood values impressively improved.

CONCLUSION

In this small case series, two patients with MM developed TMA due to carfilzomib treatment (CFZ-TMA), the second patient as a late-onset form. Even though TMA could have been elicited by influenza in the second patient and occurred after ASCT in both patients, with cases of TMA post-transplantation in MM being described, a relation of TMA and carfilzomib treatment was most likely. In both patients, treatment with eculizumab over two months efficiently treated TMA without recurrence and with both patients remaining responsive months after TMA onset. Taken together, we describe two cases of TMA in MM patients on carfilzomib-combination treatment, showing similar courses of this severe adverse reaction, with good responses to two months of eculizumab treatment.

Management of acute kidney injury in symptomatic multiple myeloma

Symptomatic multiple myeloma is commonly complicated by acute kidney injury through various mechanisms. The most frequent is the precipitation of monoclonal free light chains with uromodulin in the distal tubules, defining light chain cast nephropathy. Early diagnosis and identification of the cause of acute kidney injury are required for optimizing management and avoiding chronic kidney injury that strongly affects quality of life and patient survival. In light chain cast nephropathy, often manifesting with severe acute kidney injury, renal recovery requires urgent intervention based on vigorous rehydration, correction of precipitating factors, and efficient anti-plasma cell chemotherapy to rapidly reduce the secretion of nephrotoxic free light chains. Currently, the association of the proteasome inhibitor bortezomib with high-dose dexamethasone is the standard regimen in newly diagnosed patients. The addition of another drug such as cyclophosphamide or an immunodulatory agent may improve free light chain response but raises tolerance concerns in frail patients. Further studies are warranted to confirm the role of anti-CD38 monoclonal antibodies, whose efficacy and tolerance have been documented in patients without renal impairment. Despite controversial results from randomized studies, recent data suggest that in patients with light chain cast nephropathy and acute kidney injury requiring dialysis, the combination of chemotherapy with free light chain removal through high-cutoff hemodialysis may increase renal response recovery rates. Kidney biopsy may be helpful in guiding management and assessing renal prognosis that appears to depend on the extent of cast formation and interstitial fibrosis/tubular atrophy. Because of continuous improvement in life expectancy of patients with multiple myeloma, renal transplantation is likely to be increasingly considered in selected candidates.