Dual time-point FDG PET/CT and FDG uptake and related enzymes in lymphadenopathies: preliminary results.

PURPOSE: The purpose of this study was to determine the ability of dual time-point (DTP) PET/CT with (18)F-FDG to discriminate between malignant and benign lymphadenopathies. The relationship between DTP FDG uptake and glucose metabolism/hypoxia markers in lymphadenopathies was also assessed. METHODS: Patients with suspected lymphoma or recently diagnosed treatment-naive lymphoma were prospectively enrolled for DTP FDG PET/CT (scans 60 min and 180 min after FDG administration). FDG-avid nodal lesions were segmented to yield volume and standardized uptake values (SUV), including SUVmax, SUVmean, cSUVmean (with partial volume correction), total lesion glycolysis (TLG) and cTLG (with partial volume correction). Expression of glucose transporter-1 (GLUT-1), hexokinase-II (HK-II), glucose-6-phosphatase (G6Pase) and hypoxia-inducible factor-1alpha (HIF-1alpha) were assessed with immunohistochemistry and enzyme activity was determined for HK and G6Pase. RESULTS: FDG uptake was assessed in 203 lesions (146 malignant and 57 benign). Besides volume, there were significant increases over time for all parameters, with generally higher levels in the malignant lesions. The retention index (RI) was not able to discriminate between malignant and benign lesions. Volume, SUVmax, TLG and cTLG for both scans were able to discriminate between the two groups statistically, but without complete separation. Glucose metabolism/hypoxia markers were assessed in 15 lesions. TLG and cTLG were correlated with GLUT-1 expression on the 60-min scan. RI-max and RI-mean and SUVmax, SUVmean and cSUVmean on the 60-min scan were significantly correlated with HK-II expression. CONCLUSION: RI was not able to discriminate between malignant and benign lesions, but some of the SUVs were able to discriminate on the 60-min and 180-min scans. Furthermore, FDG uptake was correlated with GLUT-1 and HK-II expression.

The real-world use and efficacy of pomalidomide for relapsed and refractory multiple myeloma in the era of CD38 antibodies.

Pomalidomide-dexamethasone (Pd) has been a standard care treatment for relapsed and refractory multiple myeloma since 2013. However, the outcomes of Pd after exposure to CD38 antibodies are not known. Here we describe the real-world use and efficacy of pomalidomide in a Danish, nationwide cohort of daratumumab-exposed patients. We identified 328 patients that were treated with pomalidomide. Of these, 137 received Pd, 65 daratumumab-pomalidomide-dexamethasone (DPd), 43 pomalidomide-cyclophosphamide-dexamethasone (PCd), 19 carfilzomib-pomalidomide-dexamethasone (KPD), 11 pomalidomide-bortezomib-dexamethasone (PVd), and 52 pomalidomide in other combinations. Patients treated with Pd in this cohort had a partial response or better (≥ PR) rate of 35.8% and median time to next treatment (mTNT) of 4.9 months, almost identical to the results of previous prospective clinical trials. Although treatment with the various pomalidomide-containing triplet regimens resulted in higher ≥ PR rates (PCd: 46.5%, PVd: 63.6%, DPd: 55.4%, KPd: 63.2%), the mTNT achieved was not significantly better than with Pd in most cases (PCD: 5.4, PVD: 5.3, DPD: 4.7 months). The exception to this was KPd (mTNT 7.4 months), but this regimen was mainly used earlier in the course of the disease (median time from diagnosis 2.3 years vs. 3.7-4.3 years). The most important predictor of outcomes was not the choice of index regimen (p = 0.72), but prior exposure (p = 0.0116). Compared to CD38 antibody-naïve patients, triple-class-exposed patients achieved reduced ≥ PR rate (38.0% vs. 47.3%), shorter mTNT (4.0 vs. 5.9 months), and shorter median overall survival (12.4 vs. 24.2 months) with pomalidomide treatment.