Lenalidomide in Pretreated Mantle Cell Lymphoma Patients: An Italian Observational Multicenter Retrospective Study in Daily Clinical Practice, the Lenamant Study

Mantle cell lymphoma (MCL) is an uncommon type of non- Hodgkin lymphoma (NHL) comprising <10% of all newly diagnosed patients. Classified as an aggressive NHL subtype, MCL has the worst prognosis of B-cell subtypes owing to its aggressive clinical disease course and incurability with standard chemo-immunotherapy. Conventional first-line therapy for bulky or advanced disease primarily consists of chemotherapy combined with rituximab, with possible consolidation with autologous stem cell transplantation for younger patients in remission to improve overall patient outcomes. However, options for relapsed MCL are limited although several single agents have been studied. Lenalidomide is available in Italy for patients with MCL (without any other therapeutic options) since May 2011, based on a local disposition of the Italian Drug Agency (AIFA) issued according to a national law (Law 648/96: "medicinal products that are provided free of charge on the national health service"). An observational retrospective study was conducted in 24 Italian hematology centers with the aim to improve information on efficacy and safety of lenalidomide use in real practice. Seventy patients received lenalidomide for 21/28 days with a median of 8 cycles. Doses (range 5-25 mg/day) were according to hematologic parameters. At the end of therapy there were 22 complete responses (31.4%), 9 partial responses, 6 stable diseases and 33 progressions with an overall response rate of 44.3%. Sixteen patients (22.9%) received lenalidomide in combination either with dexamethasone (N=12) or with rituximab (N=4). At 62 months overall survival (OS) was 26.2% (median reached at 33 months) and disease free survival (DFS) 37% at 42 months: 14/22 patients are in continuous complete response with a median of 26 months. We compared patients who received lenalidomide alone with patients who received lenalidomide in combination with other drugs: OS and DFS did not differ. Progression free survivals are significantly different: at 56 months 36% in combination group vs 13% in patients who received lenalidomide alone (p=0.04, hazard ratio 0.52). Toxicities were manageable, even if 17 of them led to an early drug discontinuation. Two secondary malignancies occurred: a myelodysplastic syndrome and a lung cancer after 10 and 15 months of therapy, respectively. There is a boundary zone in the passage from phase III to phase IV trials, i.e. from experimental to marketing and free use phases: in this zone we can find named patient program, compassionate and off-label use and, in Italy, request based on a local disposition. Despite the known potential bias of all the observational studies, reports on the real life experience make an important contribution to medical knowledge prior to market authorization: lenalidomide therapy is effective and tolerable also in compassionate use patients with good survival. Our results, in fact, are superimposable to those obtained in clinical trials.