Regorafenib-induced renal-limited thrombotic microangiopathy: a case report and review of literatures

Cancer-Associated Thrombotic Microangiopathy: Literature Review and Report of Five Cases

Thrombotic microangiopathy (TMA) is an anatomopathological lesion mediated by endothelial dysfunction and characterized by the creation of microthrombi in small vessels. In patients with cancer, it may be due to toxicity secondary to chemotherapy, tumor embolization, or hematopoietic progenitor transplantation. Cancer-associated TMA is an underestimated entity that generally appears in the final stages of the disease, although it may also be the initial manifestation of an underlying cancer. Support treatment is necessary in all cases and, depending on the cause, different targeted therapies may be used. The prognosis is very poor. In this article we present a comprehensive review of the existing literature on the physiological mechanisms of cancer-associated TMA. Afterwards, five clinical cases will be presented of patients who developed TMA and were diagnosed in our Department in 2023. We present a discussion of the different causes that triggered the condition, the possible reasons behind the underestimation of this pathology, and the measures that may be adopted.

Fruquintinib-induced renal-limited thrombotic microangiopathy: a case report

BACKGROUND

Fruquintinib is a highly selective inhibitor of vascular endothelial growth factor receptor (VEGFR). Currently, there are no reported cases of fruquintinib causing kidney-restrictive thrombotic microangiopathy (TMA) in the available Chinese and foreign literature.

CASE PRESENTATION

In this case report, we presented a 73-year-old patient receiving fruquintinib for metastatic colon cancer, manifesting abundant proteinuria, in which kidney-restrictive TMA was also diagnosed through renal biopsy. As far as we were concerned, this was the frst reported in terms of fruquintinib-induced kidney-restrictive TMA confrmed by renal biopsy.

CONCLUSION

This case indicates that fruquintinib may result in kidney-restrictive TMA, which is a rare but life-threatening complication of cancer treatment drug. Therefore, regular monitoring of proteinuria and blood pressure is imperative for all patients undergoing anti-VEGF drug therapy. And renal biopsy should be promptly conducted to facilitate early detection of thrombotic microangiopathy.

Immunoregulation mechanism of VEGF signaling pathway inhibitors and its efficacy on the kidney

Angiogenesis and immunosuppression are closely related pathophysiologic processes. Widely prescribed in malignant tumor and proliferative retinal lesions, VEGF signaling pathway inhibitors may cause hypertension and renal injury in some patients, presenting with proteinuria, nephrotic syndrome, renal failure and thrombotic microangiopathy. VEGF signaling pathway inhibitors block the action of both VEGF-A and VEGF-C. However, VEGF-A and VEGF-C produced by podocytes are vital to maintain the physiological function of glomerular endothelial cells and podocytes. There is still no effective treatment for kidney disease associated with VEGF signaling pathway inhibitors and some patients have progressive renal failure even after withdrawal of the drug. Recent studies reveal that blocking of VEGF-A and VEGF-C can activate CD4 +and CD8+ T cells, augment antigen-presenting function of dendritic cells, enhance cytotoxicity of macrophages and initiate complement cascade activation. VEGF and VEGFR are expressed in immune cells, which are involved in the immunosuppression and cross-talk among immune cells. This review summarizes the expression and function of VEGF-A and VEGF-C in the kidney. The current immunoregulation mechanisms of VEGF signaling pathway inhibitors are reviewed. Finally, combinate strategies are summarized to highlight the proposal for VEGF signaling pathway inhibitors.

Renal Disorders with Oral Tyrosine Kinase Inhibitors in Metastatic Colorectal Cancer: An Analysis from the FDA Adverse Event Reporting System Database

BACKGROUND

this study assessed the nephrotoxicity of regorafenib (REG) and encorafenib (ENC) in metastatic colorectal cancer (mCRC) through an analysis of reports from the US Food and Drug Administration's Adverse Event Reporting System (FAERS) database.

METHODS

descriptive and disproportional analyses were performed for all reports using ENC and REG as the primary suspect.

RESULTS

A total of 379 reports had at least one renal adverse drug reaction (ADR), and these ADRs were mainly related to REG (93.1%). Potential safety signals for REG included chromaturia (n = 44; ROR = 12.00, CI 95% = 8.92-16.16; IC = 2.36, IC025-IC075 = 2.06-2.66), hydronephrosis (10; 8.70, 4.67-16.19; 1.85, 1.23-2.47), nephrotic syndrome (7; 5.73, 2.73-12.03; 1.47, 0.73-2.21), renal impairment (53; 4.16, 3.17-5.45; 1.39, 1.12-1.66), dysuria (19; 3.06, 1.95-4.81; 1.06, 0.61-1.52), renal failure (38; 1.66, 1.20-2.28; 0.49, 0.17-0.81), and acute kidney injury (AKI) (43; 1.46, 1.08-1.97; 0.37, 0.07-0.67). For ENC, consistent disproportionalities were observed for AKI (n = 11; ROR = 3.79, CI 95% = 2.09-6.90; IC = 1.32, IC025-IC075 = 0.72-1.91) and dysuria (4; 6.50, 2.43-17.39; 1.86, 0.88-2.85).

CONCLUSIONS

these findings highlight some not extensively reported renal ADRs that require further investigations to better characterize the safety profiles of REG and ENC in patients with mCRC.

Chemotherapy-Associated Thrombotic Microangiopathy

Thrombotic microangiopathy (TMA) is a syndrome of microangiopathic hemolytic anemia and thrombocytopenia with end-organ dysfunction. Although the advent of plasma exchange, immunosuppression, and complement inhibition has improved morbidity and mortality for primary TMAs, the management of secondary TMAs, particularly drug-induced TMA, remains less clear. TMA related to cancer drugs disrupts the antineoplastic treatment course, increasing the risk of cancer progression. Chemotherapeutic agents such as mitomycin-C, gemcitabine, and platinum-based drugs as well as targeted therapies such as antiangiogenesis agents and proteasome inhibitors have been implicated in oncotherapy-associated TMA. Among TMA subtypes, drug-induced TMA is less well-understood. Treatment generally involves withdrawal of the offending agent and supportive care targeting blood pressure and proteinuria reduction. Immunosuppression and therapeutic plasma exchange have not shown clear benefit. The terminal complement inhibitor, eculizumab, has shown promising results in some cases of chemotherapy-associated TMA including in re-exposure. However, the data are limited, and unlike in primary atypical hemolytic uremic syndrome, the role of complement in the pathogenesis of drug-induced TMA is unclear. Larger multicenter studies and unified definitions are needed to elucidate the extent of the problem and potential treatment strategies.