Early Mortality and Aggressive Presentation Lead to Poor Outcomes in Patients with Newly Diagnosed Double Hit and Triple Hit Multiple Myeloma

INTRODUCTION

mSMART classifies high-risk Multiple Myeloma patients into Double Hit and Triple Hit Myeloma (DH/THM) on the basis of the number of high-risk cytogenetic abnormalities detected. The outcome of these patients with the use of proteasome inhibitors and IMiDs with upfront Auto HSCT is not known in the real-world setting. We retrospectively studied the outcome of these patients in a resource constrained setting.

METHODS

The case records of all newly diagnosed multiple myeloma patients who fulfilled the criteria for active myeloma between January 2018 and December 2020 were identified. The diagnosis of double hit and triple hit myeloma was based on mSMART classification (Presence of two or more of the following: IgH-FGFR3 translocation, IgH-MAF translocation, TP53 deletion, gain of chromosome 1q). Their case records were retrieved and information regarding baseline characteristics, therapy and outcomes was noted.

RESULTS

A total of 55 patients with newly diagnosed DH/THM were treated at our center during the study period. Median age of the cohort was 60 years with almost an equal number of male and female patients (M= 26; F= 29). Renal failure (serum creatinine >2.0mg/dl) was present in 33 patients (60%) while bone lesions, anemia (Hemoglobin <10 gm/dl) and hypercalcemia (serum calcium >12mg/dl) were present in 44 (80%), 51 (92.7%) and 24 (43.6%) patients respectively. Six patients (10.9%) fulfilled the criteria for plasma cell leukemia.

All but 2 patients had gain of 1q with at least 3 copies. The most common cytogenetic combination was IgH-FGFR3 translocation with gain of 1q, which was seen in 28 patients (50.9%). This was followed by co-occurrence of TP53 deletion with gain of chromosome 1q in 11 patients (20%). Nine patients (16.4%) had triple hit myeloma.

Bortezomib was used in the initial therapy of 43 patients (78.2%) and IMiDs (lenalidomide, thalidomide and pomalidomide) were used in the initial therapy of 32 patients (58.2%). Most patients received triplet therapy (N=32; 58.2%) with the most common regimen being RVd. Nine patients (16.4%) died within the first month of diagnosis and another 7 died in next month [15 patients in 2 months (29.1%)]. The most common cause of death within 2 months was progressive disease (N=13; 81.3%). Twenty-two patients (40%) achieved VGPR or better with anti-myeloma therapy and 7 patients (12.7%) underwent autologous HCT. Of the 39 evaluable patients, 21 patients (53.8%) relapsed during follow up with a median EFS of 8 months. Of the 7 patients who underwent transplant, 5 patients have had a follow-up of more than 1 year, of whom 3 have relapsed. One patient with post-transplant relapse died with progressive disease and CMV colitis.

Median follow up of the entire cohort was 11 months (Range- 0 to 35 months). After excluding patients who died within the first 2 months of diagnosis, the median follow up was 14 months (Range- 3 to 35 months). Thirty-three patients (60%) patients died during follow-up. The most common cause of death was active or progressive disease (25 patients, 78.1%). Median OS for the cohort was 13 months. On univariate analysis, survival was better for patients without renal injury at presentation (29 months vs 6 months; p=0.007) and patients with <5% circulating plasma cells (14 months vs 2 months; p=0.045). Patients who achieved VGPR had a better OS than patients who did not (Not reached vs 3 months; p=0.000) as did patients who underwent auto transplant (Not reached vs 10 months; p=0.023). OS did not significantly differ with TP53 deletion status, or number of copies of 1q (3 or greater than 3). In the multi-variate analysis, presence of renal failure (Hazard ratio- 2.663; p-0.017) and >5% circulating plasma cells (Hazard ratio- 3.082; p-0.020) were significantly associated with increased risk of mortality, while achievement of VGPR or better with therapy was associated with longer survival (Hazard ratio- 0.174; p-0.001).

DISCUSSION

The outcome of DH/THM remains poor in the real-world setting. The outcome was not affected by specific high-risk cytogenetic abnormalities or their combination in our study. Progressive disease within the first two months of diagnosis was the most common cause of death in more than 1/3 ^rd of the patients. Novel therapies and protocols are required to improve outcomes for this group of multiple myeloma patients.