The Role of Novel Agents on Reversibility of Renal Impairment in Newly Diagnosed Patients with Multiple Myeloma; a Single Center Experience on 112 Patients,

Abstract 3961

Renal impairment (RI) is a frequent complication of multiple myeloma (MM). Proteasome inhibitors and immunomodulatory drugs (IMiDs) are used as frontline therapy for MM but their effect on renal function recovery has not been clearly defined. To address this issue we studied 112 patients with newly diagnosed MM and RI who were treated in the Department of Clinical Therapeutics of the University of Athens, over the last decade. RI was defined as an estimated glomelural filtration rate (eGFR) ≤60 ml/min, using the simplified MDRD formula. Patients were divided into three groups; group T included 53 patients who received thalidomide-based regimens (with dexamethasone alone, with dexamethasone and melphalan or cyclophosphamide, or with VAD); group B included 30 patients who received bortezomib-based regimens (with dexamethasone alone, with dexamethasone and thalidomide or with cyclophosphamide) and group L included 29 patients who received lenalidomide-based regimens (with dexamethasone or with melphalan and prednisone). Lenalidomide dose was adjusted for the degree of RI according to current recommendations. Renal complete response (CRrenal) was defined as a sustained increase of baseline eGFR to >60 ml/min, renal partial response (PRrenal) as an increase of eGFR from <15 to 30–50 ml/min and renal minor response (MRrenal) as sustained improvement of baseline eGFR of <15 ml/min to 15–29 ml/min, or, if baseline eGFR was 15–29 ml/min, improvement to 30–59 ml/min. Patients in groups T and L were older than those of group B (p=0.0001). Anemia (Hb <10 g/dl) was more frequent in patients of group L (p=0.007). There were no significant differences in the severity of RI, or other clinical and laboratory parameters among the three groups. An improvement of renal function, recorded as MRrenal or better, was achieved more frequently in patients treated with bortezomib-(83%) or thalidomide-based regimens (77%) than in patients treated with lenalidomide-based regimens (55%, p=0.033). We subsequently focused our analysis in major renal responses (at least PRrenal) since this endpoint is clinically more relevant. CRrenal was achieved in 53% of patients in group T, in 70% in group B and in 34% in group L (p=0.014), while CRrenal+PRrenal rates were 55%, 80% and 38% for groups T, B and L, respectively (p=0.004). eGFR <30 ml/min was associated with a significantly lower probability of at least PRrenal (p=0.016). In multivariate analysis bortezomib-based regimens (OR: 8.8, 95% CI: 2–37, p=0.003) and thalidomide-based regimens (OR: 2.85, 95% CI: 1.01–8, p=0.046) were associated with higher probability at least PRrenal than lenalidomide-based regimens. Other factors that were independently associated with higher probability of at least PRrenal, were baseline eGFR >30 ml/min (OR: 4.85, 95% CI: 1.9–12.5, p=0.001) and age ≤65 years (OR: 3.8, 95% CI: 1.07–13.5, p=0.038). The median time to first renal response was longer for patients of group L compared to those of group T (5.5 months vs. 1.5 months, p=0.038) and it was significantly shorter for patients of group B (0.85 months, p=0.001). The median time to major renal response was 1.1 months for bortezomib-based and 2.7 months for thalidomide-based regimens, and exceeds 6 months for lenalidomide-based regimens (p=0.002). In multivariate analysis bortezomib-based regimens (OR: 3.12, 95% CI: 1.35–7.2, p=0.008) and baseline eGFR >30 ml/min (OR: 1.93, 95% CI: 1.13–3.3, p=0.015) were independently associated with a shorter time to ≥PRrenal. Myeloma response to treatment was 61%, 83% and 83% for the three treatment groups, respectively and was associated with any renal response (≥MRrenal; p=0.008) and with a major renal response (CRrenal+PRrenal; p=0.001). Among 8 patients who required dialysis (group T 4 patients, group B 4 patients), 4 patients (2 in each group) became independent of this procedure. This is the first analysis which compared the role of the three novel agents in MM patients presenting with RI. Our data indicate that novel agent-based regimens can improve renal function in the majority of patients with RI. However, bortezomib- and thalidomide-based regimens are more efficacious than lenalidomide-based regimens in this setting. Furthermore, bortezomib-based regimens act more rapidly than IMiD-based regimens even in patients with severe RI. We conclude that bortezomib-based regimens are the preferred therapy for newly diagnosed myeloma patients with RI.