A Spoiler of Two RCTs on Extracorporeal FLCs Removal (Eulite and MYRE)

At the time of Multiple myeloma (MM) diagnosis, severe AKI secondary to Myeloma Cast Nephrpathy is a common complication. Recovery of renal function is a key prognostic factor. Two RCTs have recently investigated the use of extracorporeal dialysis strategies to rapidly remove circulating monoclonal free light chains (FLC).

Waiting for final results publication, this is a spoiler of available data:

-          Eulite Study.  90 patients with severe de novo dialysis-dependent AKI secondary to biopsy–proven Myeloma cast nephropathy were randomised to receive either standard high-flux dialysis (n=47) or free light chain (FLC) removal haemodialysis using a HCO dialyzer (n=43).  Dialysis sessions in HCO group were longer (6 hours on day 0, then 8 hours on days 2, 3, 5–7, 9+10. After day 12, participants received 8 hours of haemodialysis on alternate days. After day 21, if patients still required renal support the dialysis schedule was reduced to 6 hours three times per week) and more frequent than the conventional dialysis received by the control arm (4h x3/wk). All patients received standardised chemotherapy (bortezomib based regime). The primary endpoint of the study I, i.e. independence of dialysis at 3 months from enrolment, was achieved in 55.8% of patients in HCO group and 51.6% in standard HF-HD group (p=0.65). An increase in mortality was reported in the treatment group mainly due to delay in chemotherapy and infection.

-          MYRE Study. Patients with severe de novo dialysis-dependent AKI secondary to biopsy–proven Myeloma cast nephropathy received 21-day courses of Bortezomib and dexamethasone (BD), reinforced by cyclophosphamide after 3 cycles in the absence of haematological response (HR). Patients were randomized to receive  conventional high-flux dialysis or  intensive HD (8 sessionsof 5 hours over the first 10 days, then thrice weekly) using a HCO dialyzer. Baseline characteristics in the control arm (n=48) and HCO arm (n=46) were close, including similarly high serum FLC levels (median 6,015mg/L).  HD independence was achieved in 33% and 43% (p= 0.31) at 3 and in 37.5% and 60 % (p=0.03) at 6 months, in the control and HCO arms, respectively. HR rate at 3 months based on FLC was 48% in control and 59% in HCO groups (p=0.29). At 12 months, 17 pts have died (10 vs 7).  

Differences in clinical outcomes could be theoretically justified by the more intensive treatment regimen adopted in Eulite Study.