Persistence of minimal residual disease in bone marrow predicts outcome in follicular lymphomas treated with a rituximab-intensive program.

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.

Chlorambucil plus rituximab with or without maintenance rituximab as first-line treatment for elderly chronic lymphocytic leukemia patients.

In a phase II trial, we evaluated chlorambucil and rituximab (CLB-R) as first-line induction treatment with or without R as maintenance for elderly chronic lymphocytic leukemia (CLL) patients. Treatment consisted of eight 28-day cycles of CLB (8 mg/m(2) /day, days 1-7) and R (day 1 of cycle 3, 375 mg/m(2) ; cycles 4-8, 500 mg/m(2) ). Responders were randomized to 12 8-week doses of R (375 mg/m(2) ) or observation. As per intention-to-treat analysis, 82.4% (95% CI, 74.25-90.46%) of 85 patients achieved an overall response (OR), 16.5% a complete response (CR), 2.4% a CR with incomplete bone marrow recovery. The OR was similar across Binet stages (A 86.4%, B 81.6%, and C 78.6%) and age categories (60-64 years, 92.3%; 65-69, 85.2%; 70-74, 75.0%; ≥75, 81.0%). CLB-R was well tolerated. After a median follow-up of 34.2 months, the median progression-free survival (PFS) was 34.7 months (95% CI, 33.1-39.5). TP53 abnormalities, complex karyotype, and low CD20 gene expression predicted lack of response; SF3B1 mutation and BIRC3 disruption low CR rates. IGHV mutations significantly predicted PFS. R maintenance tended towards a better PFS than observation and was safe and most beneficial for patients in partial response and for unmutated IGHV cases. CLB-R represents a promising option for elderly CLL patients.

Fludarabine, cyclophosphamide, and rituximab in patients with advanced, untreated, indolent B-cell nonfollicular lymphomas: phase 2 study of the Italian Lymphoma Foundation.

BACKGROUND: Indolent nonfollicular non-Hodgkin B-cell lymphomas (INFLs) are clonal mature B-cell proliferations for which treatment has not been defined to date. METHODS: In this phase 2 study of patients with advanced INFL, the authors evaluated the efficacy and safety of first-line rituximab, fludarabine, and cyclophosphamide (FCR) as induction immunochemotherapy (rituximab 375 mg/m(2) intravenously on day 1 of each cycle and on days 1 and 14 of cycles 4 and 5; fludarabine 25 mg/m(2) intravenously on days 2-4, cyclophosphamide 250 mg/m(2) intravenously on Days 2-4) every 28 days for 6 cycles followed by a maintenance phase with 4 infusions of rituximab (375 mg/m(2) intravenously on day 1) every 2 months for responders. RESULTS: Forty-seven patients were enrolled. Among 46 evaluable patients (28 men; median age, 59 years), 19 were diagnosed with lymphoplasmacytic lymphoma, 21 were diagnosed with small lymphocytic lymphoma, and 6 were diagnosed with nodal marginal zone lymphoma. The overall response rate after maintenance was 89.1% with a 67.4% complete remission (CR) rate (CR/unconfirmed CR) and a 21.7% partial response rate. After a median follow-up of 40.9 months, the failure-free survival and progression-free survival rates both were 90.1%, and the overall survival rate was 97.4%. The main toxicity was hematologic, and related grade 3 and 4 neutropenia was observed in 55.3% of patients. CONCLUSIONS: FCR induction therapy followed by a short maintenance phase is a highly effective regimen with acceptable toxicity.

Dexamethasone plus rituximab yields higher sustained response rates than dexamethasone monotherapy in adults with primary immune thrombocytopenia.

Previous observational studies suggest that rituximab may be useful in the treatment of primary immune thrombocytopenia (ITP). This randomized trial investigated rituximab efficacy in previously untreated adult ITP patients with a platelet count of 20 x 10(9)/L or less. One hundred three patients were randomly assigned to receive 40 mg/d dexamethasone for 4 days with or without 375 mg/m(2) rituximab weekly for 4 weeks. Patients who were refractory to dexamethasone alone received salvage therapy with dexamethasone plus rituximab. Sustained response (ie, platelet count > or = 50 x 10(9)/L at month 6 after treatment initiation), evaluable in 101 patients, was greater in patients treated with dexamethasone plus rituximab (n = 49) than in those treated with dexamethasone alone (n = 52; 63% vs 36%, P = .004, 95% confidence interval [95% CI], 0.079-0.455). Patients in the experimental arm showed increased incidences of grade 3 to 4 adverse events (10% vs 2%, P = .082, 95% CI, -0.010 to 0.175), but incidences of serious adverse events were similar in both arms (6% vs 2%, P = .284, 95% CI, -0.035 to 0.119). Dexamethasone plus rituximab was an effective salvage therapy in 56% of patients refractory to dexamethasone. The combination of dexamethasone and rituximab improved platelet counts compared with dexamethasone alone. Thus, combination therapy may represent an effective treatment option before splenectomy. This study is registered at http://clinicaltrials.gov as NCT00770562.

Lessons for the clinic from rituximab pharmacokinetics and pharmacodynamics.

The anti-CD20 antibody rituximab (RTX; Rituxan®, MabThera®) was the first anti-cancer antibody approved by the US Food and Drug Administration in 1997 and it is now the most-studied unconjugated therapeutic antibody. The knowledge gained over the past 15 y on the pharmacodynamics (PD) of this antibody has led to the development of a new generation of anti-CD20 antibodies with enhanced efficacy in vitro. Studies on the pharmacokinetics (PK) properties and the effect of factors such as tumor load and localization, antibody concentration in the circulation and gender on both PK and clinical response has allowed the design of optimized schedules and novel routes of RTX administration. Although clinical results using newer anti-CD20 antibodies, such as ofatumumab and obinutuzumab, and novel administration schedules for RTX are still being evaluated, the knowledge gained so far on RTX PK and PD should also be relevant for other unconjugated monoclonal antibody therapeutics, and will be critically reviewed here.

Rituximab maintenance compared with observation after brief first-line R-FND chemoimmunotherapy with rituximab consolidation in patients age older than 60 years with advanced follicular lymphoma: a phase III randomized study by the Fondazione Italiana Linfomi.

PURPOSE: To evaluate the efficacy of rituximab maintenance in 60- to 75-year-old patients with advanced follicular lymphoma responding to brief first-line chemoimmunotherapy followed by rituximab consolidation. PATIENTS AND METHODS: A total of 234 treatment-naive 60- to 75-year-old patients began chemoimmunotherapy with four monthly courses of rituximab, fludarabine, mitoxantrone, and dexamethasone (R-FND) followed by four weekly cycles of rituximab consolidation. Of these, 210 patients completed the planned treatment, and 202 responders were randomly assigned to rituximab maintenance (arm A) for 8 months, once every 2 months for a total of four doses, or to observation (arm B). RESULTS: Median ages in arms A and B were 66 and 65 years, respectively. After induction and consolidation therapy, the overall response rate was 86%, with 69% complete remissions (CR). After a 42-month median follow-up from diagnosis, 3-year progression-free survival (PFS; the primary end point) and overall survival (OS) were 66% (95% CI, 59% to 72%) and 89% (95% CI, 85% to 93%), respectively. After randomization, 2-year PFS was 81% for rituximab maintenance versus 69% for observation, with a hazard ratio of 0.74 (95% CI, 0.45 to 1.21; P = .226), although this was not statistically significant. No differences between the two arms were detected for OS. Overall, the regimen was well-tolerated. The most frequent grade 3 to 4 toxicity was neutropenia (25% of treatment courses), with 13 infections. Two toxic deaths (0.8%) occurred during induction treatment. CONCLUSION: A brief R-FND induction plus rituximab consolidation achieved excellent results with high CR and PFS rates, supporting the feasibility of this regimen in patients older than 60 years. A short rituximab maintenance did not achieve a statistically significant PFS improvement over observation.

Monitoring of minimal residual disease after CHOP and rituximab in previously untreated patients with follicular lymphoma.

Minimal residual disease (MRD) following sequential administration of CHOP and rituximab was studied in previously untreated patients with follicular lymphoma. At diagnosis, the presence of Bcl-2/IgH-positive cells in the peripheral blood (PB) and/or bone marrow (BM) was demonstrated in all patients (n = 128) by polymerase chain reaction (PCR) analysis. Patients who achieved a clinical response following CHOP but remained PCR-positive were eligible for rituximab (375 mg/m(2) intravenously, weekly for 4 weeks). After CHOP, 57% achieved a complete response (CR), 37% a partial response (PR), and 6% were nonresponders (NR). At this stage, patients proving PCR-negative (n = 41) or failing to achieve a clinical response (n = 8) were excluded from rituximab treatment. Seventy-seven patients received rituximab and entered a scheduled MRD follow-up program. At the first molecular follow-up (+12 weeks), 59% had converted to PCR negativity in the BM and PB, with a further increase documented at the second control (+28 weeks) with 74% PCR negative. At the last molecular follow-up (+44 weeks), 63% of the patients remained PCR negative. At 3 years, the estimated overall survival of all patients is 95% (95% confidence interval [CI], 86-98). For patients achieving PCR-negative status following CHOP and therefore excluded from rituximab treatment, freedom from recurrence (FFR) was 52% (95% CI, 28-71). For patients treated with rituximab, a durable PCR-negative status was associated with a better clinical outcome since FFR was 57% (95% CI, 23-81) compared with 20% (95% CI, 4-46) in patients who never achieved or lost the molecular negativity (P <.001).