{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T01:47:31Z","timestamp":1782352051555,"version":"3.54.5"},"reference-count":42,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T00:00:00Z","timestamp":1782259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background\/Objectives: Patients with relapsed\/refractory multiple myeloma (RRMM) have poor survival outcomes and limited treatment options. The increasing utilization of multiagent therapies for earlier lines of treatment and novel drug classes including BCMA-targeting agents in subsequent lines of therapy has created a need for innovative treatment platforms in patients who have relapsed after or are refractory to these current standard-of-care approaches. Iopofosine I 131 is a 131iodide (131I)\u2013phospholipid conjugate that exploits the selective uptake and retention of phospholipid ethers through lipid rafts to facilitate tumor delivery of 131I. Methods: The objective of this phase 1 dose-escalation study was to assess the safety and tolerability of single and fractionated dose schedules of iopofosine I 131 + low-dose dexamethasone in heavily pretreated patients with RRMM. Results: The most common AEs overall were cytopenias, notably thrombocytopenia (93.5%), lymphopenia (74.2%), anemia (71%), leukopenia (61.3%), and neutropenia (58.1%). All patients experiencing hematologic adverse events recovered from those events with median time of recovery 21 days post-nadir. Nonhematologic adverse events were mostly limited to Grade 1 and 2. Dose-limiting toxicities included four Grade 4 thrombocytopenia events lasting longer than 7 days, one Grade 4 neutropenia, and one Grade 3 insomnia. The DMC determined 31.25 mCi\/m2 was the maximum tolerated dose in the single-dose group, and 20 mCi\/m2 \u00d7 2 doses was the maximum tolerated dose in the fractionated-dose group. For patients monitored through 85 days following the first infusion, 22 of 26 (84.6%) achieved stable disease after treatment, and 4 of 26 (15.4%) achieved a partial response. Conclusions: A favorable safety and tolerability profile and preliminary clinical activity support further development of iopofosine I 131 in RRMM.<\/jats:p>","DOI":"10.3390\/cancers18132044","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T01:03:56Z","timestamp":1782349436000},"page":"2044","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Phase I Trial of Iopofosine I 131 and Dexamethasone in Patients with Relapsed\/Refractory Multiple Myeloma"],"prefix":"10.3390","volume":"18","author":[{"given":"Sikander","family":"Ailawadhi","sequence":"first","affiliation":[{"name":"Division of Hematology\/Oncology, Mayo Clinic, Jacksonville, FL 32224, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7458-1504","authenticated-orcid":false,"given":"Jennifer L.","family":"Peterson","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL 32224, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kate","family":"Oliver","sequence":"additional","affiliation":[{"name":"Cellectar Biosciences, Florham Park, NJ 07932, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5890-4692","authenticated-orcid":false,"given":"Jarrod","family":"Longcor","sequence":"additional","affiliation":[{"name":"Cellectar Biosciences, Florham Park, NJ 07932, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6975-1086","authenticated-orcid":false,"given":"Natalie","family":"Callander","sequence":"additional","affiliation":[{"name":"Division of Hematology\/Oncology and Palliative Care, University of Wisconsin Carbone Cancer Center, Madison, WI 53706, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.amjmed.2022.08.030","article-title":"Multiple myeloma for the primary care provider: A practical review to promote earlier diagnosis among diverse populations","volume":"136","author":"Mikhael","year":"2023","journal-title":"Am. 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