Iopofosine I 131 for the treatment of RRMM: Interim data from CLOVER-1

At the Society of Nuclear Medicine and Molecular Imaging (SNMMI) Annual Meeting 2023, interim data were shared from the CLOVER-1 clinical trial (NCT02952508) of iopofosine I 131 (CLR 131) for the treatment of relapsed/refractory multiple myeloma (MM).¹ Here, we share the latest data.

Iopofosine I 131 is a small molecule phospholipid drug conjugate designed to selectively deliver the cytotoxic radioisotope iodine-131 to cancer cells. Fast track designation was granted to iopofosine I 131 by the U.S Food & Drug Administration (FDA) in May 2019; coverage of this by the Multiple Myeloma Hub can be found here.

CLOVER-1¹

CLOVER-1 is an ongoing phase II clinical trial evaluating iopofosine I 131 in relapsed/refractory B-cell hematologic malignancies, including MM. Interim topline data include the clinical outcomes of 64 patients with relapsed/refractory MM, regardless of dosing arm, and data from the 28 patients dosed at >60 mCi total administered dose (TAD). Patients were further subcategorized into post-BCMA immunotherapy, triple-class refractory, or quad-class refractory in the >60 mCi TAD cohort.

Interim efficacy data

Key efficacy data, regardless of dosing arm; >60 mCi TAD and <60 mCi TAD (n = 64):

• Overall response rate (ORR): 28%
• Clinical benefit rate: 70%
• Disease control rate: 92%

Interim data >60 mCi TAD

Key overall efficacy and safety data (n = 28):

• Efficacy
  • ORR: 32%
  • Clinical benefit rate: 75%
  • Disease control rate: 85.7%
• Safety
  • Grade 3 or 4 thrombocytopenia: 63.5%
  • Anemia: 62.5%
  • Neutropenia: 62.5%
  • Decreased white blood cell count: 50%

Key efficacy data in the highly refractory patient subgroups:

• Triple-class refractory (n = 18)
  • ORR: 46%
  • Median progression-free survival: 3.4 months
• Quad-class refractory (n = 6)
  • ORR: 50%
• Post-BCMA relapsed/refractory (n = 6)
  • ORR: 50%
  • Median progression-free survival: 3.3 months