EFFICACY OF LENALIDOMIDE-BASED AND BORTEZOMIB-BASED REGIMENS IN THE FIRST RELAPSE OF 144 MULTIPLE MYELOMA PATIENTS: A SINGLE CENTRE EXPERIENCE

ABSSUB-3256

Background: The introduction of novel agents, such as proteasome inhibitors and immunomodulatory drugs, has substantially changed the treatment paradigm of multiple myeloma (MM). It is not yet clear whether some of the novel agents are significantly better than others for the first relapse of MM.

Aims: In this retrospective study, we have analyzed the outcomes of patients (pts) with the first relapse of MM treated with lenalidomide-based (L) regimens (n=72) or bortezomib-based (B) regimens (n=72) with aims to compare the efficacy of these therapies. Both treatment groups are comparable in baseline clinical parameters including age, clinical stages according to ISS and DS staging systems, the type of M-protein, presence of renal impairment and in the first-line therapy of MM.

Methods: Clinical stages according to ISS were the following: stage 1 in 32% of pts (46/144), stage 2 in 43% of pts (62/144) and stage 3 in 25% of pts (36/144). Renal insufficiency was presented in 19% of pts (27/144). Median age was 69 years (range: 49-83). Median follow-up from start of treatment was 32 months.

Lenalidomide-based (L) regimens were used in 72 pts; lenalidomide+alkylating agent+ dexamethasone: 54 cases (75%), lenalidomide + dexamethasone: 15 cases (21%), alone lenalidomide: 3 cases (4%). Patients were treated with lenalidomide 25 mg daily (day 1-21, repeating of cycle on day +28); in cases with renal impairment the dose was 10 mg daily. Bortezomib-based (B) regimens were used in 72 pts; bortezomib+alkylating agent+ dexamethasone: 58 cases (81%), bortezomib+dexamethasone: 11 cases (15%), alone bortezomib: 3 cases (4%). Bortezomib was used in standard dose 1.3 mg/m² subcutaneously on days 1, 4, 8, 15. The cycle repeated on day 21-28 for up to 9 cycles or until progression. Median of L and B treament cycles was 5, range 1-9.

Results: In the lenalidomide-based group, overall response rate (ORR) was 56%, 10% of pts achieved the complete response (CR), 21% of pts were in very good partial response (VGPR), 25% of pts in partial response (PR), 8% of pts had minimal response (MR) or stable disease (SD) and 35% of pts had progression of disease. Median time to progression (TTP) from the start of relapse treatment was 18.4 months, median overall survival (OS) was 38.3 months.

In the bortezomib-based group, overall response rate (ORR) was 51% , 13% of pts were in CR, VGPR was achieved in 16% of pts, PR in 22% of pts, MR or SD in 16% of pts, progression was observed in 33% of pts. Median TTP and OS from start of bortezomib treatment were 18.2 and 40.8 months, respectively.

Summary/Conclusion: The lenalidomide-based and bortezomib-based regimens are effective in treatment of the first relapse MM with ORR 51-56%. Medians of TTP and OS are similar for both treatment groups. According to our findings, there are no significant differences between treatment regimens containing either lenalidomide or bortezomib for the first relapse of MM.

 Keywords: Bortezomib, Myeloma, Relapse

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