We assessed the prognostic value of minimal residual disease (MRD) within the ML17638 phase 3 trial from the Fondazione Italiana Linfomi, investigating the role of rituximab maintenance in elderly follicular lymphoma (FL) patients after a brief first-line chemoimmunotherapy. MRD for the bcl-2/IgH translocation was determined on bone marrow cells in a centralized laboratory belonging to the Euro-MRD consortium, using qualitative and quantitative polymerase chain reactions (PCRs). Of 234 enrolled patients, 227 (97%) were screened at diagnosis. A molecular marker (MM) was found in 51%. Patients with an MM were monitored at 8 subsequent times. Of the 675 expected follow-up samples, 83% were analyzed. Conversion to PCR negativity predicted better progression-free survival (PFS) at all post-treatment times (eg, end of therapy: 3-year PFS, 72% vs 39%; P < .007). MRD was predictive in both maintenance (83% vs 60%; P < .007) and observation (71% vs 50%; P < .001) groups. PCR positivity at the end of induction was an independent adverse predictor (hazard ratio, 3.1; 95% confidence interval, 1.36-7.07). MRD is a powerful independent outcome predictor in FL patients who receive rituximab-intensive programs, suggesting a need to investigate its value for decision-making. This trial was registered at www.clinicaltrial.gov as #NCT01144364. Key Points PCR negativity is a strong outcome predictor after rituximab-intensive immunochemotherapy at multiple posttreatment times. PCR is predictive even when maintenance is delivered, and accumulation of PCR-negative results further reduces the likelihood of relapse.

We here describe a novel method for MYD88^L265P mutation detection and minimal residual disease monitoring in Waldenström Macroglobulinemia, by droplet digital PCR, in bone marrow and peripheral blood cells, as well as in circulating cell free DNA. Our method shows a sensitivity of 5.00E-05, by far superior to the widely used allele-specific polymerase chain reaction (1.00E-03). Overall, 291 unsorted samples from 148 patients (133 Waldenstrom 11 IgG-lymphoplasmacytic lymphoma and 4 IgM-monoclonal gammopathy of undetermined significance), 194 baseline and 97 follow-up, were analyzed. 122/128 (95.3%) bone marrow and 47/66 (71.2%) baseline peripheral blood samples scored positive for MYD88^L265P. Moreover, to investigate whether MYD88^L265P by droplet digital PCR could be used for minimal residual disease monitoring, mutation levels were compared with IGH-based minimal residual disease analysis in 10 patients, showing to be as informative as to the classical, standardized but not yet validated in Waldenström Macroglobulinemia, IGH-based minimal residual disease assay (r²=0.64). Finally, MYD88^L265P detection performed by droplet digital PCR on plasmatic circulating tumor DNA from 60 patients showed a good correlation with bone marrow (bone marrow median mutational value 1.92E-02, plasmatic circulating tumor DNA value: 1.4E-02, peripheral blood value: 1.03E-03). This study indicates that droplet digital PCR MYD88^L265P assay is a feasible and sensitive tool for mutational screening and minimal residual disease monitoring in Waldenström Macroglobulinemia. Both unsorted bone marrow and peripheral blood samples can be reliably tested, as well as circulating tumor DNA, that represents an attractive, less invasive alternative to bone marrow for MYD88^L265P detection.

Purpose: Duration of first remission is important for the survival of patients with multiple myeloma. Experimental Design: From the CoMMpass study (NCT01454297), 926 patients with newly diagnosed multiple myeloma, characterized by next-generation sequencing, were analyzed to evaluate those who experienced early progressive disease (PD; time to progression, TTP ≤18 months). Results: After a median follow-up of 39 months, early PD was detected in 191/926 (20.6%) patients, 228/926 (24.6%) patients had late PD (TTP >18 months), while 507/926 (54.8%) did not have PD at the current follow-up. Compared with patients with late PD, patients with early PD had a lower at least very good partial response rate (47% vs. 82%, P < 0.001) and more frequently acquired double refractoriness to immunomodulatory drugs (IMiD) and proteasome inhibitors (PI; 21% vs. 8%, P < 0.001). Patients with early PD were at higher risk of death compared with patients with late PD and no PD (HR, 3.65; 95% CI, 2.7–4.93; P < 0.001), showing a dismal median overall survival (32.8 months). In a multivariate logistic regression model, independent factors increasing the early PD risk were TP53 mutation (OR, 3.78, P < 0.001), high lactate dehydrogenase levels (OR, 3.15, P = 0.006), λ-chain translocation (OR, 2.25, P = 0.033), and IGLL5 mutation (OR, 2.15, P = 0.007). Carfilzomib-based induction (OR, 0.15, P = 0.014), autologous stem-cell transplantation (OR, 0.27, P < 0.001), and continuous therapy with PIs and IMiDs (OR, 0.34, P = 0.024) mitigated the risk of early PD. Conclusions: Early PD identifies a high-risk multiple myeloma population. Further research is needed to better identify baseline features predicting early PD and the optimal treatment approaches for patients at risk.