Results of a recent study suggest that for patients with relapsed/refractory multiple myeloma (RRMM) initiating anti-CD38 monoclonal antibody therapy, imaging through the use of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) may help predict survival outcomes. The study results were reported in the journal Cancers.

Therapy targeting CD38 may help with survival for patients with RRMM, but there is variability in outcomes with this approach. The researchers conducting this study had an aim of identifying a prognostic tool to be used in patients with RRMM at the start of treatment with an anti-CD38 monoclonal antibody.

In this study of patients treated at Cochin Hospital in Paris, France, 38 consecutive patients with RRMM received whole-body FDG PET/CT scans prior to starting therapy with an anti-CD38 monoclonal antibody. Additional patient, clinical, and laboratory data were also evaluated. The researchers analyzed these data to identify parameters associated with progression-free survival (PFS) and overall survival (OS) in these patients.


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The study cohort had a median age of 73 years, and patients had received a median of 3 prior lines of therapy (range, 2-10). The median time from diagnosis of symptomatic MM to the indication for anti-CD38 therapy was 4.8 years (range, 0.1-16.9). A total of 32 patients received daratumumab, and 6 patients received isatuximab. The median followup after starting immunotherapy was 10 months (range, 1-21).

The median PFS for the total population was 12.6 months (95% CI, 5.5-12.6), and the median OS had not been reached. A total of 9 patients had died, with 7 deaths associated with myeloma, 1 related to acute myeloid leukemia, and 1 to COVID-19.

Baseline International Prognostic Index (IPI) scores were 1 for 42% of the patients, 2 for 37% of the patients, and 3 for 21% of the patients. The majority of patients (71%) had visible lesions on FDG PET/CT scan, and the presence of >3 focal lesions (FLs) was seen in 19 patients.

Higher initial IPI scores and the presence of >3 FLs were both associated with worse PFS and OS, and these features were additionally linked to each other. In multivariable analysis, both the initial ISS score (P =.010) and the presence of >3 FLs (P =.025) were independent predictors of poorer PFS.

When analyzed together, the researchers considered an ISS score of 3 or 4 in addition to the presence of >3 FLs to form the basis of a high-risk group. This group had a median PFS of 3.1 months and a median OS of 8.5 months, which were both not reached in the rest of the patients.

The researchers cautioned that the study had a small sample size, but they considered the results to provide useful information on the use of FDG PET/CT in assessing prognosis in patients with RRMM. “Combined with the initial ISS, this simple PET criterion could improve the risk stratification of RRMM patients and thus enable the earlier and better identification of ultra-risk patients,” the researchers concluded in their report.

Reference

Fouquet G, Wartski M, Dechmi A, et al. Prognostic value of FDG-PET/CT parameters in patients with relapse/refractory multiple myeloma before anti-CD38 based therapy. Cancers (Basel). 2021;13(17):4323. doi:10.3390/cancers13174323