The clinical relevance of imatinib plasma trough concentrations in chronic myeloid leukemia. A Belgian study.

This retrospective multicenter study in patients with chronic myeloid leukemia in chronic phase was undertaken to confirm the clinical relevance of imatinib plasma concentrations monitoring in daily practice. Forty-one patients, with 47 imatinib plasma measurements, were analyzed during treatment with imatinib given at a fixed 400mg daily dose. A significant inverse relationship of imatinib concentration with the patients' weight was observed (Pearson's test: p=0.02, R2=0.1). More interestingly, patients with poor response (switched to another tyrosine kinase inhibitor because of imatinib failure, or because of disease progression after an initial response) displayed a significantly lower mean imatinib concentration as compared to patients maintained on imatinib (822ng/mL vs 1099ng/mL; Student's t-test, p=0.04). Failure or disease progression occurred more often in patients in the lowest quartile of imatinib concentrations compared to patients in the highest quartile (p=0.02, logrank test). No correlation could be established with other biological or clinical parameter, including complete cytogenic response and major molecular response. IN CONCLUSION: in patients treated with imatinib at a fixed daily dose of 400mg, imatinib plasma concentrations decreased with increasing body weight and were lower in patients switched to another tyrosine kinase inhibitor due to imatinib failure. Systematic determination of imatinib plasma trough levels should be encouraged in such patients.

Early stage follicular lymphoma: what is the clinical impact of the first-line treatment strategy?

BACKGROUND: Less than 20% of patients with follicular lymphoma (FL) present with Ann Arbor Stage I or II disease at diagnosis. Numerous therapeutic options exist, however radiation therapy is considered the standard of care for early-stage disease based on single-institution or retrospective series. Our aim was to revisit the outcome of patients with localized FL in the rituximab era. PATIENTS AND METHODS: We analyzed the characteristics and outcomes of 145 early-stage FL patients, who were retrospectively divided into six groups according to their initial treatment: watchful waiting (WW), chemotherapy alone (CT), radiotherapy alone (RT), combined radiotherapy and chemotherapy (RT-CT), rituximab alone (Ri), and immunochemotherapy (Ri-CT). RESULTS: Of the 145 patients, 84 (57.9%) had stage I disease and 61 (42.1%) stage II. The complete response (CR) rate varied from 57% for the Ri group to 95% for the RT-CT group. Overall survival (OS) at 7.5 y of patients treated after 2000 was better than that of those treated prior to 2000. OS did not significantly differ from one treatment to another. In contrast, a significant difference was found for progression-free survival (PFS) at 7.5 y, which favored Ri-CT (60%) therapy versus the others (p=0.00135). CONCLUSION: Delayed therapy initiation was associated with a similar OS than that observed in patients receiving immediate intervention. The "watchful waiting" strategy may thus be proposed as first-line therapy, similar to stage III and IV FL patients with a low tumor burden. However, when treatment is required, immunochemotherapy appears to be the best option.

Activity and safety of combined rituximab with chlorambucil in patients with mantle cell lymphoma.

We evaluated the combination of rituximab with chlorambucil in patients with mantle cell lymphoma (MCL) not eligible for aggressive therapy. Fourteen patients (male/female: 9/5) were included (two newly diagnosed, 12 relapsed/refractory). The toxicities were neutropenia, thrombopenia and infection. Nine (64%) patients responded; five (36%) achieved complete remission and four (29%) achieved partial remission. The median progression-free survival for responders was 26 months (95% CI, 4-48). Marrow polymerase chain reaction negativity was attained in seven responders. These results suggest that this schedule may have notable antitumour activity in patients with MCL, including patients in relapse after autologous stem cell transplantation.

Recurrent seizure and sustained encephalopathy associated with dimethylsulfoxide-preserved stem cell infusion.

We report the case of a patient who received two infusions of dimethylsulfoxide (DMSO) cryopreserved autologous peripheral blood progenitor cells (PBPCs) after myeloablative chemotherapy for a relapsing lymphoma. A 49-year-old man presented an episode of tonic-clonic seizure over a few minutes after the start of each infusion and developed a profound and sustained but reversible encephalopathy with coma after the second infusion. The patient's neurological condition correlated well with the electrophysiological findings (electroencephalogram and multimodality evoked potentials) and, to a lesser extent, with the radiological abnormalities (magnetic resonance imaging). Severe but reversible neurological complications may occur with the infusion of PBPCs cryopreserved with DMSO.