Patients with Relapsed or Progressive Multiple Myeloma Treated with Lenalidomide in the Compassionate Use Program. Spanish Registry, Preliminary Analysis.

Introduction and Objectives. Lenalidomide is a new inmunomodulatory drug which has shown effectiveness, in combination with dexamethasone, in relapsed or progressive Multiple Myeloma (MM). In our country, little experience outside clinical trials exists since lenalidomide is only currently available in the compassionate use program, for patients with advanced MM. With the purpose of sharing the clinical practical experience with this drug, we considered it interesting to gather the outstanding data on the use of lenalidomide in a multicentric registry, throughout the Spanish scope. We present the preliminary results of this registry.

Patients and methods. We designed a registry, canalized through GEM-PETHEMA, in which main clinical data of MM patients relapsed or progressive treated with lenalidomide within the compassionate use program, were collected. The decision to treat these patients was prior to and independent of the decision to make this registry and was only based on clinical criteria. The selected patients had at least one response assessment.

Results. 19 valid questionnaires have been received, 14 patients (pts.) being assessable for response. The treatment was started between 03/06 and 04/07. Average age: 63 years (40–77); 9 men and 5 women. Type of MM: IgG 9 pts, IgA 3 pts, 1 non-secretory, 1 Bence Jones K. Average M-protein 3.25 g/dL(SD: 3,32); average creatinine 1,05 (SD: 0.36); average bm plasma cells infiltration: 36%. Median lines of previous treatments: 4 (2–8). 13 pts had received bortezomib, 8 pts had received thalidomide, and 7 had undergone autologous PBSCT. 7 pts showed extramedullary plasmocytomas.2 patients received the standard dose (25 mg daily, P.O. 21 days every 4 weeks). 2 patients received lower doses. All the patients, except one, received Dexamethasone simultaneously (average 56 mg per week). Prophylaxis for DVT: 7 pts with LWMH and 3 pts with salicylates. 4 patients did not receive prophylaxis. At the time of data collection 10 patients where still on the treatment. Lenalidomide was discontinued in 2 patients due to progression (median time to progression 6 months (1–8); 1 pts underwent PBSCT after reaching PR and discontinued the treatment due to stable disease after 6 months. Response: 2 CR (14%), 1 VGPR (7%), 6 PR (43%), 3 SD (21%). Among the 9 pts with a favorable response (64%): 8 had previously received bortezomib, 4 had received thalidomide, and 4 had undergone PBSCT - Toxicity: Neutropenia G3: 5 pts/G4: 2 pts; 5 patients needed G-CSF. Thrombocytopenia G3: 3 pts/G4: 3 pts. Skin rash in 1 pt. Neither TVP/TEP nor neutropenic fever were observed.

Conclusions. Although a more detailed analysis and a longer follow-up is needed the results of our registry are consistent with other published clinical trials: lenalidomide associated with dexamethasone induces durable objective responses in a high percentage of patients with relapsed or progressive MM, after several treatment lines. The tolerance of this drug is acceptable, being the mielosuppression the most relevant toxicity. The role of this drug at low dose for long term maintenance have to be investigated.