Lenvatinib-induced renal failure: two first-time case reports and review of literature.

INTRODUCTION: Lenvatinib (LEN) is a multi-kinase anti-angiogenic drug recently approved in several cancers. LEN is not easily manageable due to its complex safety profile. Proteinuria and renal failure (RF) were reported among the most frequent LEN-induced adverse events (AEs), often leading to discontinuations or dose modifications. Understanding the pathogenesis of these AEs could ameliorate the management of LEN-induced renal toxicity. Areas covered: We present two cases of LEN-induced renal failure (LIRF) with different pathogenesis. 1) LIRF with severe proteinuria in a man treated for a metastatic papillary thyroid carcinoma. Kidney biopsy showed a glomerular damage secondary to LEN, having excluded other causes of RF. 2) LIRF without proteinuria in a woman with metastatic adenoid cystic carcinoma of minor salivary gland. A tubulointerstitial nephropathy was supposed by clinical evaluation and laboratory tests. Effective management was obtained by oral steroids without interrupting LEN. Expert opinion: The case 1 presented for the first time the histological picture of LIRF with a classical glomerular damage leading to secondary proteinuria and tubular failure. Case 2 showed an alternative LIRF pattern of likely tubulointerstitial injury without proteinuria. These reports reflect two sides of the same coin, both to be considered in case of LIRF.