OUTCOMES IN NEWLY DIAGNOSED MULTIPLE MYELOMA WITH RENAL INVOLVEMENT: RETROSPECTIVE STUDY FROM TERTIARY CARE CENTRE IN NORTHERN INDIA

Introduction:

Of all newly diagnosed multiple myeloma patients, 20-40% have renal impairment as defined by IMWG 2016 criteria. Newly diagnosed multiple myeloma (NDMM) patients with renal involvement(RI) have been reported to have significantly inferior survival compared to those without renal involvement. In the post- bortezomib era, although outcome of such patients has improved in Western countries, data from resource poor LMIC countries is sparse. Younger age at diagnosis, advanced disease at presentation, higher risk of infections, limited finances and supportive care could potentially attribute to inferior outcomes in MM with renal impairment. Therefore, we aimed to investigate the factors that predict renal response and overall survival when using bortezomib-based regimens in NDMM patients with renal involvement.

Methods:

It was a single-centre retrospective study in a tertiary care institute in patients of NDMM-RI from January 2020 to January 2024. Patient details were obtained from electronic records. The diagnosis of multiple myeloma was made based on IMWG 2014 criteria. Renal involvement (RI) was defined as estimated glomerular filtration rate [eGFR] <60 mL/min per 1·73 m2 as per CKD EPI 2021 equation as per IMWG 2014 criteria. The etiology was defined as definite cast nephropathy if proven by kidney biopsy, and presumed cast nephropathy if involved light chain was more than 500mg/L and presence of predominant light chain proteinuria in cases where biopsy was not performed. Primary outcomes of interest were overall survival and renal response. Hematological and renal outcomes were assessed as per IMWG 2016 criteria.

Results:

Among 325 of patients of NDMM,143 (44%) patients were found to have RI. Baseline, laboratory and myeloma characteristics are as shown in Table 1 and Table 2. The median age of patients was 57 years (range 27-86 years). Median eGFR was 17ml/min/1.73m2(range 3-60ml/min/1.73m2) and majority of the patients were in advanced ISS stage. (ISS III = 110 (76.9%)). Out of 143 patients, kidney biopsy was performed in 36 patients (25.2%) – 15(41.7%) cast nephropathy, 8(22.2%) MIDD, 4(11.1%), AL amyloidosis, 3(8.3%) were PGNMID, 2(5.6%) showed acute tubular injury, 2(5.6%) showed chronic tubulointerstitial nephritis and one each of FSGS and light chain proximal tubulopathy. Hence, overall cast nephropathy (presumed + biopsy proven) was seen in 94(65.7%). Cytogenetics were available for 107 (74.8%) (Table 3). Forty-three (30.1%) patients received at least one session of hemodialysis at presentation. Renal response was seen in 103(72%) patients with median time to renal response of 2 months (range 1 week -26 months), and 28(out of 43; 65%) became dialysis independent over a median time of 14 days (Range 7-24 days). At median follow-up period 13 months (range 1-55 months), 18(12.6%) patients had died. Higher beta2microglobulin (OR = 1.04; 95% CI [1.00-1.08], p=0.012) and hematologic response worse than VGPR (OR = 7.83; 95% CI [2.85-21.51], p=<0.00) were identified as predictors of poor renal recovery on multivariate analysis. Patients who had renal recovery had improved survival as compared to patients with no renal response. (Median OS-not achieved vs. 13 months, p=<0.001). On multivariate analysis, patients who attained hematologic response of VGPR or better and presence of light chain myeloma had significantly improved survival.

Conclusions:

Renal response was seen in almost 3/4th of the patients with NDMM-RI which was associated with improved overall survival along with hematologic response.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.