Outcomes of Newly Diagnosed Myeloma Patients Requiring Dialysis: Dialysis Independence Is Associated with Rapid Myeloma Response and Predicts for Longer Survival

Renal failure (RF) is a common severe complication of symptomatic myeloma and may be severe enough to require extrarenal dialysis in approximately 1-5% of newly diagnosed patients. Severe RF is associated with high risk of early death and increased morbidity. Immediate effective anti-myeloma therapy and vigorous supportive care are the cornerstones of management. The use of high cutoff hemodialysis to rapidly reduce the load of nephrotoxic light chains seems to offer limited additional benefit in patients requiring dialysis when treated with bortezomib-based therapies (Cook M et al EHA 2016, Abs P270). However, outside clinical trials, there are limited data focusing on the management and outcomes of NDMM patients requiring dialysis. Thus, we analyzed the outcomes of consecutive newly diagnosed patients with RF requiring dialysis, who were managed and treated in a single center.

Between 1995 and 2016, 50 patients (6.2% of 796 consecutive NDMM) who were treated in the Department of Clinical Therapeutics (Athens, Greece) presented with severe RF requiring dialysis. The analysis included all patients who received at least one dose of any therapy. All patients received similar supportive care and dialysis with regular filters. The median age of patients requiring dialysis was 69 years (37-88), 68% were >65 years of age. At presentation 92% had Hb <10 g/dl, 5 (10%) had platelet count <100x10⁹/l, 12 (24%) had hypeprcalcemia (Ca ≥11.5 mg/dl) and 24 (48%) had elevated LDH (≥250 IU/l). All patients had elevated β2-microglobulin (median 21.7 mg/L, range 6-60 mg/l) and all were ISS stage 3. High risk cytogenetics (N=40) were present in 38% and per R-ISS, 75% were R-ISS-3 and 25% R-ISS-2. Myeloma was light chain only in 42%, IgA in 26%, IgG in 30% and IgD in 1 patient (2%); light chain was κ in 38 (64%) and λ in 18 (36%). Among patients who retained urine flow at presentation, median 24h Bence Jones proteinuria was 2.2 gr (range 0.1-8.8 gr). Among patients with available FLCs, median level of involved free light chain (iFLC) was 9080 mg/l (range 119-201000 mg/l).

Treatment was bortezomib-based in 41 (82%) patients: 11 (22%) had bortezomib + dexamethasone (VD), 21 (42%) VD + cyclophosphamide (VCD), 8 (16%) VD + thalidomide (VTD), 1 (2%) VD + doxorubicin (PAD). Nine (18%) patients received non-bortezomib containing regimens: 5 (10%) thalidomide plus high dose dexamethasone and 4 (8%) VAD with high dose dexamethasone. Twenty-five (50%) patients became dialysis independent at a median time of 158 days from start of therapy (range 4-336 days). Age ≤65 years was associated with higher probability (75% vs 38%) and shorter time to dialysis independence (51 vs 336 days; p=0.027); no other baseline factors were associated with dialysis independence in univariate analysis. Among patients treated with bortezomib, three-drug combinations (n=30) vs VD alone (N=11) were associated with higher probability of dialysis independence (57% vs 27%; p=0.06). Among patients who became dialysis independent 12 received VCD, 4 VTD, one PAD, 3 VD, 2 MDT, 2 VAD and one T-VAD.

Median follow up for all patients was 33 months and median survival was 29 months. Early mortality (within 2 months from start of therapy) was 16%, mostly due to infectious complications. On intent to treat, 64% achieved ≥PR (CR: 6%, VGPR: 32%, PR: 26%); among patients who survived >2 months, ≥PR was achieved by 76%. At 2-month landmark, patients who achieved ≥PR within the first 2 months had higher dialysis independence rates (68% vs 27%, p=0.004). Becoming dialysis independent was associated with a significant improvement in survival (median OS of 63 vs 22 months of patients who remained on dialysis; p=0.002), even after exclusion of early deaths. Notably, the survival of patients who discontinued dialysis was similar to that of the rest of patients (57 months). High dose melphalan (HDM) followed by autologous stem cell transplantation was performed in five patients while on dialysis. Four of them (80%) become dialysis independent approximately one month after HDM.

In conclusion, about 6% of NDMM present with renal failure requiring dialysis but half of them can become dialysis independent after bortezomib-based therapy, without the use of special filters, especially if they achieve a rapid myeloma response. VD-based triplets increase the probability of renal response over VD alone and independence from dialysis is associated with a significant improvement in prognosis.