Systemic vasculitis associated with vemurafenib treatment: Case report and literature review

Large-vessel vasculitis possibly induced by BRAF and MEK inhibitors for BRAF V600E positive lung adenocarcinoma

The combination therapy of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors is approved for treating patients with BRAF V600E-positive tumours, including melanoma and lung cancer. Several case reports indicated autoimmune side effects associated with the use of BRAF and MEK inhibitors. Still, the effects of these drugs on the immune system were not fully elucidated. Here, we report a patient with large-vessel vasculitis diagnosed after initiation of treatment with dabrafenib and trametinib for BRAF V600E-positive metastatic lung adenocarcinoma. She was a never-smoker woman in her early 70s who presented with a chronic cough and was diagnosed with BRAF V600E-positive metastatic lung adenocarcinoma by transbronchial lung biopsy. She was successfully treated with prednisolone and methotrexate while BRAF and MEK inhibitors were continued. We should be careful about autoimmune diseases using BRAF and MEK inhibitors.

A Spotlight on Drug-Induced Vasculitis

PURPOSE OF REVIEW

Drug-induced vasculitis (DIV) is a rare form of vasculitis related to the use of various drugs. DIV primarily affects small to medium size vessels, but it can potentially involve vessels of any size. Differentiating between primary systemic vasculitis and DIV can be challenging; however, it is crucial, so that the offending agent can be discontinued promptly.

RECENT FINDINGS

The clinical phenotype of DIV is protean and depends on the size of the affected vessels. It ranges from arthralgias, to an isolated cutaneous rash, to severe single or multi-organ involvement. While withdrawal of the offending drug is the most important step in management, a significant number of patients require immunosuppressive therapy for varying periods of time. DIV can affect any vascular bed size, leading to protean vasculitic syndromes. Increased awareness among general practitioners, specialty, and subspecialty physicians is crucial for early recognition, and withdrawal of drug for better outcomes.

BRAF/MEK inhibitor-associated nephrotoxicity in a real-world setting and human kidney cells

Acute kidney injury (AKI) associated with cancer chemotherapy can be life-threatening. Inhibitors of rapidly accelerated fibrosarcoma kinase B (BRAF)-mutants and mitogen-activated extracellular signal-regulated kinase (MEK) administered as combination therapy are effective against BRAF-mutant melanoma, but drug-associated AKI events were reported after marketing. Here, we examined the nephrotoxicity of two BRAF inhibitors, vemurafenib and dabrafenib, and two MEK inhibitors, cobimetinib and trametinib, in a real-world setting and human kidney cells. Target drug-associated AKI signals were detected by reporting odds ratio (ROR) derived from report data in the Food and Drug Administration Adverse Events Reporting System database. In-vitro cytotoxicity was evaluated in proximal renal tubular epithelial cells (RPTEC), glomerular endothelial cells (GEnC), and glomerular epithelial cells (GEpC).

RESULTS

AKI RORs associated with vemurafenib [ROR, 3.28; confidence interval (CI), 2.91-3.69] and cobimetinib (ROR, 4.40; CI, 3.55-5.45) were higher than those associated with dabrafenib (ROR, 1.35; CI, 1.15-1.60) and trametinib (ROR, 1.32; CI, 1.11-1.56). Vemurafenib reduced cell viability and increased cell death in RPTEC and GEpC at 10 μM, which was below the mean maximum concentration in blood under steady-state condition [115.7 μM (56.7 μg/mL)]. No vemurafenib-associated cytotoxicity was detected in GEnC. Mean maximum concentrations of cobimetinib, dabrafenib and trametinib did not induce cell death.

CONCLUSION

This work revealed that vemurafenib had stronger cytotoxic effects on tubular and glomerular epithelial cells than the other BRAF and MEK inhibitors. Hence, we recommend careful monitoring for clinical signs of kidney injury in patients treated with vemurafenib.

Tolerability of BRAF/MEK inhibitor combinations: adverse event evaluation and management

The inhibition of the mitogen-activated protein kinases signalling pathway through combined use of BRAF and MEK inhibitors (BRAFi+MEKi) represents an established therapeutic option in patients with BRAF-mutated, advanced melanoma. These efficient therapies are well tolerated with mostly moderate and reversible side effects and a discontinuation rate due to adverse events of 11.5%-15.7%. Median duration of therapy ranges between 8.8 and 11.7 months. Based on data from confirmatory trials, safety profiles of three BRAFi+MEKi combinations were reviewed, that is, dabrafenib plus trametinib, vemurafenib plus cobimetinib and encorafenib plus binimetinib. Many adverse events are class effects, such as cutaneous, gastrointestinal, ocular, cardiac and musculoskeletal events; some adverse events are substance associated. Fever (dabrafenib) and photosensitivity (vemurafenib) are the most common and clinically prominent examples. Other adverse events are less frequent and the association to one substance is less strong such as anaemia, facial paresis (encorafenib), neutropenia (dabrafenib), skin rash, QTc prolongation and increased liver function tests (vemurafenib). This narrative review provides recommendations for monitoring, adverse event evaluation and management focusing on the clinically relevant side effects of the three regimens.

Glomerulonephritis and granulomatous vasculitis in kidney as a complication of the use of BRAF and MEK inhibitors in the treatment of metastatic melanoma: A case report

RATIONALE

BRAF and MEK inhibitors have significantly improved the prognosis of metastatic melanoma, by inhibiting both the mitogen-activated protein kinase (MAP-kinase) pathway. They are associated with infrequent adverse kidney events. Most of these are related to the use of BRAF inhibitors and involve interstitial nephritis with acute tubular necrosis.

PATIENT CONCERNS

We report a unique case of glomerulonephritis with renal granulomatous vasculitis in a patient diagnosed with metastatic melanoma treated with BRAF and MEK inhibitors. The patient was a 55-year old woman, who presented a melanoma of the right thigh with pulmonary metastasis. Treatment started in November 2015, with Encorafenib and Binimetinib, new BRAF and MEK inhibitors, respectively. Two months after the beginning of the treatment, there was a worsening of her renal function with significant proteinuria.

DIAGNOSES

Kidney biopsy showed extracapillary proliferation in the glomeruli with a granulomatous reaction.

INTERVENTIONS AND OUTCOMES

Renal function recovered completely after withdrawal of the chemotherapy.

LESSONS

All the reported kidney adverse events secondary to BRAF and MEK inhibitors in the literature are related to the use of BRAF inhibitors. Some previous reported mechanistic investigations also provide insight between BRAF inhibitors and podocytes injuries. Therefore, encorafenib most likely is the main responsible of the disease. However, evidence has emerged that inhibition of the MAP kinase pathway could also enhance autoimmunity. Thus, binimetinib may also have played a role and the combination of BRAF and MEK inhibitors may have facilitated this autoimmune kidney disease.