IMPACT OF NUMBER OF PREVIOUS TREATMENT LINES AND PRE-TREATMENT WITH BORTEZOMIB OR LENALIDOMIDE ON EFFICACY OF BORTEZOMIB-BENDAMUSTINE-DEXAMETHASONE (BBD) IN PATIENTS WITH RELAPSED/REFRACTORY MULTIPLE MYELOMA (MM)

Introduction

The number of previous treatment lines and pre-treatment with Bortezomib (B) or lenalidomide (L) likely impacts the efficacy and tolerance of BBD in r/rMM.

Patients and methods

71 pts with r/rMM have been enrolled. Median age: 65 yrs (range 40-86), male/female: 32/39, ISS stage I/II/III: 22, 29, and 20 pts, respectively. ECOG status 0/I/II: 37, 31, and 3 pts, respectively. Previous treatment lines: 1-2: 44, 3-6: 27 pts, 43 pts had previously been exposed to B and 37 to L. Full data documentation for response evaluation (≥2 cycles) is available for 65 pts.

Treatment

Benda 70 mg/m2 day 1 + 4, B 1.3 mg/m2 and Dex 20 mg on days 1, 4, 8 and 11, q 4 wks. Planned number of treatment cycles was 8, with discontinuation after 4 cycles in case of no response. K-M survival curves were compared using the log-rank test.

Results

After a median follow up of 7.1 mos, myeloma response (ORR: CR-PR) was noted in 38 (58.5%), CR/nCR in 11 (16.9%), VGPR in 10 (15.4%), PR in 17 (26.2%), MR in 11 (16.9%), and SD in 16 (24.6%) pts. Median time to response was 77 days. Tab 1 shows response rates and PFS in pts in regards to number of previous treatment lines and pre-exposure to B, L, and to both B and L. Median OS was not reached in any of the cohorts.

G4 anemia, leucopenia and thrombopenia were reported in < 5%. Incidence of G3-4 infections and GI toxicities was low. G1-2 PNP was documented in 18% of pts at baseline and remained constant in almost all pts with only 3 developing G3 PNP and 1 G4 PNP. Univariate analysis employing age, FISH ISS, ß2M, LDH, Hb, and pre-treatment with either B or L or both revealed a significant negative correlation between combined L and B pre-treatment and ORR (p < 0.02), which in multivariate analysis also proved to be independently associated with ORR (p < 0.02). Conclusio: The BBD regimen resulted in remarkable response rate and PFS in the entire cohort of pts and in those pre-exposed to B. Pre-treatment with both B and L was associated with lower response rates and significantly shorter PFS. Median OS was not reached in the total cohort or in any of the subgroups. The regimen was well tolerated.

Disclosure

H. Ludwig: Received honoraria for speakers bureau from Mundipharma, Celgene and Janssen-Cilag. Scientific research grants from Mundipharma and Janssen-Cilag.

All other authors have declared no conflicts of interest.

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