Risk factors for the development of secondary malignancy after high-dose chemotherapy and autograft, with or without rituximab: a 20-year retrospective follow-up study in patients with lymphoma.

PURPOSE: High-dose chemotherapy with peripheral blood progenitor cell (PBPC) autograft is effective in high-risk lymphoma, particularly with the addition of rituximab; however, it is associated with risk of secondary malignancy. These issues have been addressed in a series of 1,347 patients with lymphoma treated with a high-dose sequential (HDS) program. PATIENTS AND METHODS: A total of 1,024 patients with B-cell lymphoma, 234 patients with Hodgkin's lymphoma, and 89 patients with T-cell lymphoma were treated with HDS between 1985 and 2005 at 11 Gruppo Italiano Terapie Innovative Linfomi centers. HDS was given as salvage treatment to 707 patients (52%); 655 patients (49%) received a modified HDS, with high-dose cytarabine and two consecutive PBPC harvests. Rituximab-supplemented HDS was given to 523 patients (39%). RESULTS: At a median follow-up of 7 years, the median overall survival (OS) was 16.2 years; in B-cell lymphoma the OS was significantly superior with rituximab HDS compared to HDS alone. The cumulative incidence at 5 and 10 years of secondary myelodysplasia/acute leukemia (sMDS/AL) were 3.09% and 4.52%, respectively, that of solid tumors were 2.54% and 6.79%, respectively. Factors associated with sMDS/AL were male sex and use of the second harvest PBPC for the graft; factors found to be associated with solid tumor were advanced age, post-HDS radiotherapy, and rituximab addition to HDS. Despite the increased risk of solid tumors, rituximab addition to HDS was still associated with survival advantages. CONCLUSION: This analysis has relevant implications for the design and use of intensive chemoimmunotherapy with autograft. In addition, it offers useful insights toward the understanding and prevention of tumor development.

HHV8-positive, HIV-negative multicentric Castleman's disease: early and sustained complete remission with rituximab therapy without reactivation of Kaposi sarcoma.

Multicentric Castleman's disease (MCD) is a rare lymphoproliferative disorder with systemic symptoms and poor prognosis and is characterized by an abnormal proliferation of polyclonal plasmablasts in the mantle zone of B-cell follicles. The disease is found primarily in chronic HIV carriers and is usually strictly associated with human herpes virus type 8 (HHV-8) coinfection, which is believed to play a key role in the pathogenesis of MCD. The disease is also diagnosed in HIV-negative patients, who are usually elderly or immunosuppressed; however, in about half of these cases, no evidence of HHV8 infection is found. The anti-CD20 monoclonal antibody rituximab is now the preferred treatment for HIV-positive MCD. However, it is not clear whether rituximab is effective in HIV-negative patients with MCD, particularly in the HHV8-positive subset. We report here the clinical and biologic courses of two HIV-negative, HHV8-positive patients with MCD who were treated with rituximab. In both cases, a significant clinical improvement was observed after the first two infusions, which was shortly followed by a drop in HHV8 viremia to undetectable levels. Both patients underwent complete clinical remission, which persisted without relapse at 30 and 9 months of follow-up, respectively. No reactivation of the Kaposi sarcoma found in a lymph node of one of the patients was observed. Our report, along with additional data present in the literature, suggests that rituximab may be an appropriate and safe first-line therapy for HIV-negative, HHV8-positive MCD.

New therapeutic approaches and prognostic factors in chronic myeloid leukemia.

Imatinib mesylate is now the first-choice treatment for all newly diagnosed CML patients, but despite the impressive percentage of responding patients, some CML cases show primary resistance or relapse after an initial response. Although some clinical and biological findings have been found to be associated with a lower probability of response to imatinib, at present no precise markers allowing to predict outcome for individual patients exist. The most common mechanisms of resistance to imatinib include BCR-ABL kinase domain mutations, BCR-ABL amplification and overexpression, and clonal evolution with activation of additional transformation pathways. These mechanisms are caused by the genomic instability, which characterises the Ph-positive clone. Several approaches to overcome resistance have been proposed, including novel tyrosine kinase inhibitors (TKIs) that have now reached the clinical or pre-clinical phase of evaluation. Clinical trials with these novel TKIs have shown good rates of hematologic and cytogenetic responses that appear also durable in time, but still cases of resistance are also observed, supporting the notion that genomic instability represents the major determinant affecting the final outcome of the CML patients when treated with TKIs. Understanding exactly the mechanisms leading to genomic instability of the Ph-positive cells represents therefore the real challenge for the near future.

New drugs in the treatment of chronic myeloid leukaemia / Novas drogas no tratamento da leucemia mielóide crônica

The introduction of the BCR-ABL kinase inhibitor, imatinib mesylate (Gleevec®, Novartis) led to significant changes in the treatment of chronic myeloid leukaemia (CML) patients. However, despite the impressive percentage of responding patients, some CML cases, particularly those in advanced phases of the disease, show primary resistance or relapse after the initial response. The second-generation BCR-ABL inhibitors nilotinib (Tasigna®, Novartis) and dasatinib (Sprycel®, Bristol-Myers Squibb) have shown significant activity in clinical trials in patients who failed imatinib therapy, but these agents are still incapable of inhibiting the T315I mutant of Bcr-Abl and present partial activity in advanced phases of CML. The acquired biological notions of the mechanisms of tyrosine kinase inhibitor (TKI) resistance has led to the development of new compounds, some of which have shown encouraging preliminary results in clinical trials, even against T315I mutants. In this paper we discuss the new emerging therapies which may overcome TKI resistance in CML patients.

A introdução do inibidor de tirosino quinase BCR-ABL mesilato de imatinibe (Glivec®, Novartis) levou a significantes mudanças no tratamento da LMC. Entretanto, a despeito de impressionante porcentagem de pacientes que respondem, alguns casos de LMC, particularmente em fases avançadas da doença mostram resistência primaria ou recidivas após terapêutica inicial. Inibidores de tirosino quinases de segunda geração como o nilotinibe (Tasigna®, Novartis) e o dasatinibe (Sprycel®, Bristol Myers Squibb) têm mostrado significante atividade nos estudos clínicos em paciente onde o imatinibe falhou. Porém, estes agentes não são capazes de inibir a mutação T315I do Bcr-Abl e apresentam atividade parcial em fases avançadas da LMC. As noções biológicas adquiridas sobre os mecanismos de resistência aos inibidores de TK levaram ao desenvolvimento de novos compostos alguns dos quais têm resultados preliminares encorajadores incluindo a mutação T315I. Neste trabalho nós discutimos os novos agentes emergentes e qual o potencial poderão atingir para ultrapassar a resistência aos inibidores de TK em pacientes com LMC.