PB2017: YOUNG PATIENTS WITH NEWLY DIAGNOSED MULTIPLE MYELOMA AND RENAL IMPAIRMENT: A TUNISIAN SINGLE-CENTER EXPERIENCE

Background: Patients (pts) with newly diagnosed Multiple Myeloma (NDMM) face a high risk of developing a renal impairment (RI). It is one of the most feared complications in this population due to its severe immediate consequences and its poor outcome on the prognosis and the overall survival. We report our retrospective single-center study of NDMM in young pts with RI.

Aims: This study aims to identify the incidence of renal failure (RF) in NDMM and analyze the renal response (RR), hematological response (HR), the overall survival (OS) and the prognostic impact after induction therapy.

Methods: This retrospective single-center review over 4 years (between June 2016 and December 2020) includes young pts under the age of 65 years old with NDMM with RF eligible for autologous stem cells transplantation (ASCT). RF was defined by a serum creatinine higher than 177 μmol/L and the serum Creatinine Clearance (CC) was calculated according to the MDRD formula. All pts with RF in this study were treated with Bortezomib, Thalidomide and Dexamethasone (DT) as an induction regimen.

RR and HR were defined according to the International Myeloma Working Group (IMWG14) criteria.

In addition to antimyeloma treatment, pts with RI received symptomatic treatment such as intravenous hydration, corticosteroids, correction of hypercalcemia and in some cases dialysis.

In this study, we identify the incidence of RF in NDMM and analyze the RR, HR, OS and the prognostic impact after induction therapy.

Results: We included in our study 58 pts with NDMM. The incidence of NDMM with RF at diagnosis was 48,3% (n=28), the serum creatinine level median was 213μmol/L and the serum creatinine clearance (CC) median was 23.5 ml/min.

According to the CC staging, the renal function was severely decreased in 11 cases (39%) and in the kidney failure stage in 5 cases (17%).

The MM with RF immunoglobulin type was Light chain in 11 cases (39%), IgG in 12 cases (43%) and IgA in 5 cases (18%).

After receiving symptomatic treatments of RF, 35% (n=10) of NDMM with RF pts had their renal function recovered whereas 64%(n=18) did not and 10% (n=3) needed dialysis.

After induction therapy, the serum creatinine level median was 95μmol/L and the serum CC median was 73.5ml/min

Thus, the RR was: complete in 64% (n=18), partial in 7%(n=2), minor in 18% (n=5), no response in 2 cases (7%) and one patient died before assessment.

HR after induction regimen was 74% (n=20): complete response (CR) in 4 cases (14%), very good partial response (VGPR) in 8 cases (29%) and partial response (PR) in 8 cases (29%). Among the 18 pts with complete RR, 6 pts (33%) underwent ASCT.

Pts with RF at diagnosis had a poorer OS median (18.5 months) comparing to those with normal renal function (OS median=21.5 months). The OS was significantly influenced by the degree of RF and the recovery of normal renal function (p<0.05).

Summary/Conclusion: Our single center study showed that RI occurs in 48% of the cases in NDMM at diagnosis, which is significantly higher to what is found in the literature (5-30%). It also revealed that NDMM with RI has poorer HR and OS than pts with normal renal function when both treated by a Brotezomib induction regimen followed by ASCT. The RR after supportive care measurements and antimyeloma therapy was 74%, which is slightly lower to what is found in the literature (77%). Thus, early diagnosis and rapid initiation of a triplet Brotezomib based regimen for this high-risk group is essential and improves renal outcomes in RI pts.