The US Food and Drug Administration (FDA) approved iobenguane I 131 injection for the treatment of adults and adolescents that are at least 12 years old with unresectable rare tumors of the adrenal gland (pheochromocytoma or paraganglioma) that have spread beyond the original tumor site and require systemic therapy, according to a press release.1 Iobenguane is the first FDA-approved medication for this indication.

Pheochromocytomas are rare tumors of the adrenal glands that cause an overproduction of epinephrine and norepinephrine, causing hypertension and associated symptoms such as headache, sweating, rapid heart rate, chest pain, and anxiety. A pheochromocytoma occurring outside the adrenal glands is called a paraganglioma.

The FDA based its approval on findings from a single-arm phase 2 ( Identifier: NCT00874614) study, in which researchers treated 68 patients with pheochromocytoma or paraganglioma with iobenguane I 131 intravenous injection. The primary outcome for this study was the proportion of patients who had at least a 50% reduction (including discontinuation) of all antihypertension medications for 6 months or more.

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Results showed that 17 (25%) of 68 eligible patients met the primary endpoint, and 15 (22%) patients had an overall tumor response (the secondary endpoint).

The most frequently observed severe adverse events included lymphopenia, neutropenia, thrombocytopenia, increased international normalized ratio, fatigue, anemia, dizziness, nausea, and vomiting.


  1. FDA approves first treatment for rare adrenal tumors [press release]. Silver Spring, MD: U.S. Food and Drug Administration: July 30, 2018. Accessed July 30, 2018.