BACKGROUND: Patients with multiple myeloma (MM) who underwent autologous stem cell transplantation (ASCT), are known to benefit from maintenance therapy post-transplant. With signs of early relapse, physicians can either change maintenance therapy or use a new therapeutic regimen.
OBJECTIVES: The purpose of this study is to analyze the clinical outcomes beyond biochemical relapse of patients with MM on maintenance therapy. Time to next treatment (TNT), progression free survival (PFS) and overall survival (OS) are assessed. Different approaches for relapse such as increase in lenalidomide (R) dose, addition of dexamethasone (D) or Bortezomib (V) or shift to different lines of treatment are possible.
SETTING: A retrospective single center study approved by the institutional review board of the American University of Beirut Medical Center, Lebanon.
METHODS: Between January 2011 and May 2017, 51 patients with MM who underwent ASCT, received Bortezomib/Lenalidomide/Dexamethasone (VRD) consolidation and maintenance therapy, mainly lenalidomide(R) 10mg/day for 21 days every 28 days, were included. 
RESULTS:  The median age at transplant was 55 years (46-75). 46 (90%) patients received R maintenance, 3 patients received VRD maintenance for higher risk features. Median duration of R maintenance was 22 months (3-62). R dose was changed for toxicity in 17 (33%) patients (grade I-II). 29 (57%) patients relapsed. 13 (25%) patients changed treatment to different protocols.  6 patients (11%) were observed. 10 (20%) patients had increased lenalidomide dose with dexamethasone. 5 patients (31%) of these 2 groups required change of treatment later. The median follow up was 38 months (1-85). Median TNT was 32 months (7-62). At 2 years, the estimated PFS and OS were 39% and 97.5% respectively. The median OS and PFS2 (from therapy change) were 54 and 29 months for patients in the observation group versus 52 and 27 months in the R/D group as well as 45 months and 33 months with treatment change, respectively. No statistically significant difference was noted. 
CONCLUSION: Our small monocentric study is limited by its retrospective design and small sample size. However, it suggests that increasing lenalidomide dose/adding dexamethasone in selected patients can postpone change to different lines of treatment without affecting survival.

39 / Management of biochemical relapse during lenalidomide maintenance therapy post ASCT in multiple myeloma: a descriptive observational study of a single institution