Progressive erythrocytosis under lenvatinib treatment in patients with advanced hepatocellular carcinoma

PURPOSE: This manuscript reports on the occurrence of early and frequent erythrocytosis in advanced hepatocellular carcinoma (HCC) patients treated with lenvatinib. METHODS: A cohort of 23 patients with advanced HCC, treated with this antiangiogenic drug for at least one month, was retrospectively analyzed. RESULTS: These patients (82.7% men, median age 58.3, cirrhosis in 60.8%) were treated between October 2019 and September 2020 with lenvatinib, as first-line systemic therapy for 82.6% of them. For 20 patients (87%), an early and significant increase in hemoglobin (Hb) level, up to 1.41 g/dL (p < 0.001) was reported and remained elevated. Ten patients (43.5%), all men, reached erythrocytosis (Hb > 16.5 g/dL), 7 were treated with low-dose aspirin for primary thromboprophylaxis and 2 needed phlebotomy. None underwent thromboembolic complications. A significant Hb decrease was observed after treatment discontinuation (p < 0.05). Erythropoietin (EPO) serum levels also increased, which was attributed to HCC after immunostaining for EPO in liver biopsies. The Naranjo adverse drug reaction probability scale documented the relationship between erythrocytosis and lenvatinib and regression at treatment discontinuation. Erythrocytosis was hypothesized to be a class effect of anti-VEGF therapies, the magnitude of which might depend on the IC50 value of each molecule. CONCLUSION: This report documents the frequent occurrence of erythrocytosis during lenvatinib treatment for advanced HCC, likely secondary to EPO secretion by tumor cells through the antiangiogenic activity levatinib. An early and close monitoring of hematologic parameters is, thus, recommended, together with thromboprophylaxis by low-dose aspirin and phlebotomy in case of symptomatic erythrocytosis.