Last reviewed · How we verify
131I
Iodine-131 is a radioactive isotope that emits beta particles to destroy thyroid tissue and thyroid cancer cells.
Iodine-131 is a radioactive isotope that emits beta particles to destroy thyroid tissue and thyroid cancer cells. Used for Thyroid cancer (radioiodine-avid differentiated thyroid cancer), Hyperthyroidism.
At a glance
| Generic name | 131I |
|---|---|
| Sponsor | Genzyme, a Sanofi Company |
| Drug class | Radiopharmaceutical |
| Target | Sodium-iodide symporter (NIS) |
| Modality | Small molecule |
| Therapeutic area | Oncology |
| Phase | Phase 2 |
Mechanism of action
131I is taken up selectively by thyroid follicular cells through the sodium-iodide symporter, concentrating in the thyroid gland where it delivers targeted radiation to ablate normal thyroid tissue or thyroid cancer. The beta radiation causes direct cellular damage and cell death in iodine-avid tissues. This mechanism allows treatment of hyperthyroidism and radioiodine-avid thyroid cancers with relatively selective targeting to the thyroid.
Approved indications
- Thyroid cancer (radioiodine-avid differentiated thyroid cancer)
- Hyperthyroidism
Common side effects
- Hypothyroidism
- Radiation thyroiditis
- Salivary gland dysfunction
- Bone marrow suppression
- Secondary malignancy
Key clinical trials
- ImmunoPET Targeting Trophoblast Cell-Surface Antigen 2 (Trop-2) in Thyroid Cancer (NA)
- Efficacy of MEK (Trametinib) and BRAFV600E (Dabrafenib) Inhibitors With Radioactive Iodine (RAI) for the Treatment of Refractory Metastatic Differentiated Thyroid Cancer (PHASE2)
- Iodine I 131 Metaiodobenzylguanidine in Treating Patients With Recurrent, Progressive, or Refractory Neuroblastoma or Malignant Pheochromocytoma or Paraganglioma (PHASE2)
- Study of TLX101-Tx Plus Standard of Care (SoC) Versus SoC Alone for the Treatment of Patients With Recurrent Glioblastoma (PHASE3)
- Testing the Addition of 131I-MIBG or Lorlatinib to Intensive Therapy in People With High-Risk Neuroblastoma (NBL) (PHASE3)
- Iodine Uptake After a Low Iodine Diet (NA)
- 131I-Omburtamab, in Recurrent Medulloblastoma and Ependymoma (PHASE2)
- Induction Therapy Including 131 I-MIBG and Chemotherapy in Treating Patients With Newly Diagnosed High-Risk Neuroblastoma Undergoing Stem Cell Transplant, Radiation Therapy, and Maintenance Therapy With Isotretinoin (PHASE1)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- 131I CI brief — competitive landscape report
- 131I updates RSS · CI watch RSS
- Genzyme, a Sanofi Company portfolio CI