A study on the efficacy and safety of anlotinib in patients with metastatic pheochromocytoma and paraganglioma

Metastatic pheochromocytoma and paraganglioma (MPP) currently lack definitive curative therapies. The treatment of MPP presents a formidable challenge. Anlotinib hydrochloride, characterized as a multi-targeted tyrosine kinase receptor inhibitor, has demonstrated potential in this domain. This study, a phase 2 trial (NCT04860700), aimed to evaluate the efficacy and safety profiles of anlotinib hydrochloride in patients suffering from MPP. The primary objective was to determine the disease control rate (DCR) and objective response rate (ORR) as determined by the RECIST 1.1 criteria. Secondary objectives were to evaluate the biochemical response, progression-free survival (PFS), and safety. Twenty-nine patients with MPP were enrolled. We found that 24.1% (7/29) of patients discontinued the treatment after 1-2 cycles because of a significant increase in hormone levels or adverse events. Among 22 patients who could be evaluated by the RECIST 1.1 criteria, the overall DCR was 95.5% (21/22), and the ORR was 31.8% (7/22). The PFS was calculated to be 22.6 ± 3.2 months. There is no significant difference in ORR or PFS between patients with and without germline mutations. The most common adverse events included arterial hypertension (24/29, 82.8%), subclinical primary hypothyroidism (11/29, 37.9%), hyperlipidemia (10/29, 34.5%), rash (8/29, 27.6%), and fatigue (8/29, 27.6%). We conclude that among the evaluable patients, anlotinib showed promising efficacy with high DCR. Close monitoring remains essential because of treatment-related adverse events.