CLINICAL IMPORTANCE OF RENAL RECOVER ON OUTCOMES OF NEWLY DIAGNOSED MULTIPLE MYELOMA PATIENTS WITH SEVERE AND DIALYSIS-DEPENDENT KIDNEY FAILURE

Introduction. Kidney damage at the onset of multiple myeloma (MM) is observed in 20-40 % of patients, which requires renal replacement therapy in 2-4 % of cases. Deterioration in kidney function is associated with frequent complications and a decline in the quality of life, as well as carries a high risk of early death. Aim. To analyze the treatment of patients first diagnosed with MM, complicated by severe and dialysis-dependent renal failure. Materials and methods. 62 MM patients with a glomerular filtration rate of <30 ml/min /1.73 m(2) participated in a retrospective study (11.2014-11.2017) with the following inclusion criteria: the concentration of free light chains in blood serum being >500 mg/l and the selective nature of proteinuria. Diagnosed AL-amyloidosis served as the exclusion criterion. Depending on the need for haemodialysis, patients were divided into two groups: (I) those not requiring it (n = 16) and (II) dialysis-dependent patients (n = 46). Results. The induction therapy included the following bortezomib-containing regimens: VCD-41 (66.1 %), PAD-2 (3.2 %), VD-12 (19.4 %) and VMP-7 (11.3 %). High-dose consolidation along with autologous hematopoietic stem cell transplantation was performed in 10 patients (16.1 %). The overall rate of anti-myeloma response in the groups came to 64.3 % (I) and 85.3 % (II) (p = 0.047), including complete and strong complete remissions in 14.3 % (I) and 14.7 % (II) of cases. The renal response was achieved by 57.2 % and 23.5 % (p = 0.032) of patients from the first and second groups, respectively. With a median follow-up of 32.1 months, throughout the entire cohort the median of progression-free survival (PFS) amounted to 14.5 months, with a 3-year PFS of 27.4 6.6 %; whereas the median of overall survival (OS) came to 33.6 months, with a 3-year OS of 41.5 7.7 %. There are no differences between the compared groups in terms of the survival rates. In the examined patients (n = 48), the achievement of any renal response was associated with an improvement in the 3-year PFS-61.1 +/- 11.5 % versus 17.7 7.7 % (p = 0.045)-and 3-year OS-72,2 10.6 % versus 38.1 10.4 % (p= 0.069). The time elapsed between the first haemodialysis procedure and the onset of anti-myeloma chemotherapy served as the predictor value of the renal response. In the group of patients who achieved a renal response, the average time came to 8.6 (95 % confidence interval of 3.5-13.7) days, as compared to 42.5 (12.6-72.5) days for patients without a renal response (p = 0.045). Conclusion. The use of bortezomib-based regimens provides a high frequency of antitumour responses with a probability of stopping dialysis in 23.5 % of dialysis-dependent patients. Possible reasons for the low frequency of renal response include the late diagnosis of MM as a cause of kidney damage, as well as the lack of access to new anti-myeloma drugs if the induction therapy needs to be changed.