Zr-89 daratumumab immunoPET found myeloma missed by FDG PET/CT in 8 of 60 patients in phase 2
In a phase 2 trial at Sylvester Cancer Center, CD38-targeted 89Zr-DFO-daratumumab PET/CT showed biopsy-confirmed active myeloma in 13% of participants with a negative 18F-FDG scan.
Researchers at Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, compared a CD38-targeted immuno-PET tracer with standard 18F-fluorodeoxyglucose (FDG) PET/CT in 60 people with multiple myeloma. The prospective phase 2 trial was published on 3 November 2026 in Radiology. Overall detection was similar, but in 13% of participants (8 of 60) myeloma was seen only on the immuno-PET scan and was then confirmed by biopsy doi.org
Radiologydoi.orgOpen source ↗.
Trial design and tracer
The tracer, zirconium 89 (89Zr) deferoxamine (DFO)-daratumumab, is a labeled antibody directed at CD38, a protein on the surface of myeloma cells doi.org
Radiologydoi.orgOpen source ↗. Participants were enrolled between March 2022 and July 2025. Each had standard-of-care 18F-FDG PET/CT and a bone marrow biopsy, plus a research 89Zr-DFO-daratumumab PET/CT
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Radiologydoi.orgOpen source ↗.
Where the two scans showed different lesions, image-guided biopsy served as the reference standard. The McNemar test was used to compare disease detection between the two modalities doi.org
Radiologydoi.orgOpen source ↗. The median age of the 60 participants was 63 years (IQR, 57–71 years); 32 were women
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Radiologydoi.orgOpen source ↗.
Detection results
89Zr-DFO-daratumumab PET/CT showed at least one positive lesion in 43% of participants (26 of 60; 95% CI: 31, 57). 18F-FDG PET/CT did so in 47% (28 of 60; 95% CI: 33, 60). The difference in overall detection was not significant (P = .81) doi.org
Radiologydoi.orgOpen source ↗.
The eight participants positive only on the immuno-PET scan had active myeloma confirmed by biopsy. The authors concluded that CD38-targeted immuno-PET helped detect active myeloma in some participants with no signs of disease on 18F-FDG PET/CT doi.org
Radiologydoi.orgOpen source ↗.
Senior author C. Ola Landgren said the goal is to add information to existing tools rather than replace them, since blood tests, bone marrow biopsies and imaging each reveal different data. According to the release, one patient with negative standard scans and blood tests had nearly 100 myeloma sites on the immuno-PET scan, confirmed by follow-up biopsy.
Current limitations
Per the university's release, the antibody needs about a week to distribute through the body and bind to cancer cells, which complicates administration of the test. The group is developing next-generation versions based on smaller antibody fragments that reach tumors faster, aiming at a same-day examination.
