Underlying systemic mastocytosis in patients with unexplained osteoporosis: score proposal.

BACKGROUND: A score to predict the association between unexplained osteoporosis and an underlying systemic Mastocytosis (SM) is lacking. OBJECTIVE: This study aimed at identifying criteria able to predict the diagnosis of SM without skin involvement and provide an indication for bone marrow (BM) assessment. METHODS: We included 139 adult patients with unexplained osteoporosis and suspected SM. After BM evaluation, 63 patients (45.3 %) were diagnosed with SM, while the remaining 76 patients (54.7 %) negative for clonal mast cell (MC) disorders, constituted our control group. Univariate and multivariate analysis identified three independent predictive factors: age (<54 years: +1 point, >64 years: -1 point), serum basal tryptase (sBT) levels >19 ng/mL (+2 points) and vertebral fractures (+2 points). RESULTS: These variables were used to build the OSTEO-score, able to predict the diagnosis of SM before BM assessment with a sensitivity of 73.5 % and a specificity of 67.1 %. Patients with a score < 3 had a lower probability of having SM compared to patients with a score ≥ 3 (28.5 % and 71.4 %, respectively, p < 0.0001). When sBT levels were corrected for the presence of hereditary alpha-tryptasemia (HαT) using the BST calculater (https://bst-calculater.niaid.nih.gov/) recently published [1,2], the sensitivity of ΗαT-adjusted OSTEO-score increased to 87.8 %, and the specificity reached 76.1 %. Also, the positive predictive value of a score ≥ 3 increased to 85.2 %. CONCLUSIONS: Further studies are needed to validate these results and characterize the role of tryptase genotyping in patients with unexplained osteoporosis in reducing the risk of misdiagnosing patients with SM. Our proposed scoring model allows the identification of patients with the highest probability of having SM, avoiding unnecessary BM studies.

Outcomes of younger patients with mantle-cell lymphoma experiencing late relapse (>24 months): the LATE-POD study.

Patients with mantle cell lymphoma (MCL) who experience first relapse/refractoriness can be categorized into early or late progression-of-disease (POD) groups, with a threshold of 24 months from the initial MCL diagnosis. Bruton tyrosine kinase inhibitors (BTKi) are established standard treatment at first relapse, but their effectiveness as compared to chemoimmunotherapy (CIT) in late-POD patients remains unknown. In this international, observational cohort study, we evaluated outcomes amongst patients at first, late-POD beyond 24 months. Patients treated upfront with BTKi were excluded. The primary objective was progression-free survival from time of second-line therapy (PFS-2) of BTKi versus CIT. After accrual, all patients were prospectively followed-up. Overall, 385 late-POD patients were included from 10 countries. Their median age was 59 (range:19-70) years and 77% were males. Median follow-up from time of first relapse was 53 months (range:12-144). Overall, 114 patients had second-line BTKi, while 271 had CIT, consisting of rituximab-bendamustine (R-B, n=101), R-B and cytarabine (R-BAC, n=70), or other regimens (mostly cyclophosphamide-hydroxydaunorubicin-vincristine-prednisone-CHOP- or platinum-based, n=100). The two groups were balanced for clinicopathological features, and median time to first relapse (48 months for both). Overall, BTKi was associated with significantly prolonged median PFS-2 than CIT [not reached-NR vs 26 months, respectively, P=.0003], and overall survival [NR and 56 months, respectively, P=.03]. Multivariate analyses showed that BTKi was associated with lower risk of death than R-B and other regimens (hazard ratio-HR, 0.41 for R-B, 0.46 for others), but similar to R-BAC. These results may establish BTKi as the preferable second-line approach in BTKi-naïve MCL patients.