Citations

AbstractResponse assessment in light chain (AL) amyloidosis is based on serum and urine monoclonal protein studies. Newly diagnosed patients (n = 373) who achieved very good partial response or complete response (CR) to first line therapy were assessed for the survival impact of each of the monoclonal protein studies. At end of therapy (EOT), negative serum/urine immunofixation (IFE) was achieved in 61% of patients, 72% achieved normal serum free light chain ratio (sFLCR), and the median involved free light chain (iFLC) and difference between involved to uninvolved light chain (dFLC) were 17 mg/L and 5 mg/L, respectively. Overall, 46% of patients achieved a CR at EOT. At EOT, iFLC ≤20 mg/L and dFLC ≤10 mg/L were additive in survival discrimination to negative serum/urine IFE and were independent predictors of overall survival. In contrast, normalization of sFLCR did not add survival discrimination to serum/urine IFE and was not independent predictor of survival. We propose a new definition for hematological CR to include serum/urine IFE negativity plus iFLC ≤20 mg/L or dFLC ≤10 mg/L, instead of the current definition of serum/urine IFE negativity and normal sFLCR. Complete response using dFLC ≤10 mg/L had the best performance in those with significant renal dysfunction and by light chain isotype, making it the preferred partner to IFE. Validation of these results in a multicenter cohort is warranted.

AbstractThe diagnosis of primary plasma cell leukemia (pPCL) has been made by quantifying circulating plasma cells (cPCs) morphologically on a peripheral blood (PB) smear. However, this technique is not sufficiently sensitive. Multiparametric flow cytometry (MFC) provides a readily available and highly sensitive method to identify and quantify cPCs that could complement PB smear assessment. However, an optimal quantitative cutoff for cPCs by MFC to identify pPCL has not been established. Thus, a total of 591 patients newly diagnosed multiple myeloma (NDMM) patients who had their PB samples evaluated morphologically by PB smear, and immunophenotypically by MFC prior to beginning therapy were evaluated. The presence of ≥200 cPCs/μL by MFC (N = 25 or 5% of the total population) was chosen to identify patients with ≥5% cPCs by PB smear with a specificity of 99% and a sensitivity of 77%. For patients with ≥200 cPCs/μL by MFC compared to the remainder of the cohort, the median Time to next therapy (TTNT) was 18 vs 30 months and the median OS was 38 vs 70 months respectively. Thus, MFC assessment of PB can be utilized in conjunction with the morphological assessment of a PB smear to aid in improving the identification of pPCL among NDMM patients.

AbstractOur prior studies identified the prognostic significance of quantifying cPCs by multiparametric flow cytometry (MFC) in newly diagnosed multiple myeloma (NDMM) patients. We evaluated if a similar quantification of cPCs could add prognostic value to the current R‐ISS classification of 556 consecutive NDMM patients seen at the Mayo Clinic, Rochester from 2009 to 2017. Those patients that had ≥5 cPCs/μL and either R‐ISS stage I or stage II disease were re‐classified as R‐ISS IIB stage for the purposes of this study. The median time to next therapy (TTNT) and overall survival (OS) for patients with ≥5 cPCs/μL at diagnosis was as follows: R‐ISS I (N = 110) ‐ 40 months and not reached; R‐ISS II (N = 69) ‐ 30 and 72 months; R‐ISS IIB (N = 96) ‐ 21 and 45 months and R‐ISS III (N = 281) ‐ 20 and 47 months respectively. Finally, ≥ 5 cPCs/μL retained its adverse prognostic significance in a multivariable model for TTNT and OS. Hence, quantifying cPCs by MFC can potentially enhance the R‐ISS classification of a subset of NDMM patients with stage I and II disease by identifying those patients with a worse than expected survival outcome.

Summary Improvement in survival in Light chain (AL) amyloidosis has been seen over recent decades, enabling more patients to achieve long‐term survival. Patients with AL amyloidosis who survived ≥10 years from time of diagnosis ( n = 186) were the subject of this study. Ten‐year survivors represented 22% of the total population. These patients were characterized by favourable patient, organ and plasma cell features. Of note, trisomies were less common among 10‐year survivors compared to those who did not survive to 10 years. All‐time best haematological response was complete response in 67%, very good partial response in 30%, partial response in 2% and no response in 1%, with 11% having received a consolidative strategy for inadequate response to first line therapy. The overall organ response rate to first‐line therapy was 76%, which increased to 86% when considering subsequent line(s) of therapy. Forty‐seven percent of the 10‐year survivors did not require a second‐line therapy. The median treatment‐free survival (TFS) among the 10‐year survivors was 10·5 years (interquartile range 7·4‐12·2). On multivariate analysis independent predictors for TFS were the achievement of complete haematological response and lack of cardiac involvement. Long‐term survivors are increasingly seen in AL amyloidosis and present distinct patient, organ and clonal disease features.

Abstract The high-risk abnormality del(17p) can be detected by fluorescence in situ hybridization on malignant plasma cells (PCs) and has an adverse prognostic impact in patients with multiple myeloma (MM). Patients with del(17p) have reduced overall survival (OS). Patients who acquire del(17p) later during the disease course are not well described. The disease characteristics at diagnosis predicting for acquired del(17p) and its overall impact on patient survival is not known. We compared 76 patients with MM who were negative for del(17p) at diagnosis and acquired it later with 152 control MM patients who did not acquire del(17p) at a comparable time point. Patients acquired del(17p) at a median of 35.6 months (range, 4.6-116.1 months) from diagnosis of MM after a median of 2 lines of therapy (range, 1-10 lines of therapy). When compared with controls, patients with acquired del(17p) had shorter median progression-free survival (PFS) (30.1 vs 23.0 months; P = .032) and OS (106.1 vs 68.2 months; P < .001) from diagnosis. After the detection of del(17p), the median PFS was 5.4 months and the median OS was 18.1 months. High lactate dehydrogenase level (odds ratio [OR], 3.69; 95% confidence interval [CI], 1.11-12.24) and presence of t(4;14) (OR, 2.66; 95% CI, 1.09-6.48) or any high-risk translocation (OR, 2.23; 95% CI, 1.00-4.95) at diagnosis predicted acquisition of del(17p). High PC proliferative rate predicted shorter OS from detection of del(17p) (hazard ratio, 2.28; 95% CI, 1.31-3.96; P = .004). Our study shows that acquisition of del(17p) is an important molecular event associated with reduction in OS in MM. Certain baseline factors may predict acquisition of del(17p). This needs validation in prospective data sets.

AbstractPositron emission tomography‐computed tomography (PET‐CT) can identify bony lesions, assess disease burden, and detect extramedullary disease (EMD) in patients with multiple myeloma. We retrospectively reviewed records of patients who underwent PET‐CT within 60 days of a new diagnosis (before therapy commenced) to identify the nature and prognostic impact of PET‐CT abnormalities. Patients (N = 313) were seen from April 2005 through June 2017. Of the 234 patients (75%) with focal lesions (FLs), 182 (58%) had at least 3 FLs, 38 (12%) had EMD, and 204 (65%) had documented myelomatous lytic lesions. The median maximum standardized uptake value (SUVmax) for the entire cohort was 5.9 (range 1.5‐48.3). Presence of at least 3 FLs and EMD predicted inferior overall survival (OS); median OS was 57.8 months for patients with 3 or more FLs and 103.6 months for patients with fewer than 3 FLs (P = .003). The median OS was 45.5 and 71.8 months for patients with and without EMD, respectively (P = .004). No clear SUVmax cutoff was predictive of progression‐free survival or OS. PET‐CT is a valuable tool for assessing disease burden and could provide prognostic information about a contemporary cohort of patients with newly diagnosed myeloma who received treatment with novel agents.

AbstractDetection of myeloma progression (PD) relies on serial 24‐h urinary M protein measurements in patients without measurable serum M spike. We examined whether serial difference free light chain (dFLC) levels could be used as a surrogate for serial 24‐h urine M protein measurements in monitoring for PD in patients with baseline measurable urine M protein. We studied 122 patients who had serial measurement of urine M protein and serum FLC and had demonstrated PD. The median increase in dFLC with progression as defined by urine M spike was 110% (IQR: 55‐312) and median absolute increase was 74 mg/dL; while 89% of patients had dFLC increase ≥ 25%, 94% had absolute increase in dFLC > 10 mg/dL, and 98% met at least 1 of these 2 criteria at PD. In patients with baseline measurable serum FLC (n = 118), 89% had increase in dFLC ≥ 25%, 97% had dFLC increase of > 10 mg/dL, and 98% had 1 of the 2. We conclude that serial dFLC assessments can be used in place of serial 24‐h urine protein assessments during myeloma surveillance to monitor for PD. Once patients have an absolute increase in dFLC of >10 mg/dL from the nadir, a 24‐h urine collection can then be assessed to document PD as per the International Myeloma Working Group criteria.

AbstractExperience with intensive chemotherapy for relapsed/refractory multiple myeloma (RRMM) using VDT PACE regimen and its modifications (VDT PACE‐like regimens: VPLRs) outside TOTAL THERAPY trials is limited. We analyzed the outcomes of 141 patients with RRMM who received VPLRs at our center between 2006 and 2017 in an intent‐to‐treat analysis. Median age was 59.7 years and 66.7% of patients were male. A median of 2.2 years (range 0.02‐11.4) separated diagnosis of myeloma and inititation of VPLR. High‐risk cytogenetics were present in 52.4% patients. Patients received a median of 4 (range 1‐14) prior therapies, including stem cell transplant (SCT) in 66.7% patients. Ninety‐five (67.4%) patients received VDT PACE, 20 (14.2%) patients received VD PACE and 26 (18.4%) patients received other VPLRs. Patients received a median of 1 cycle (range 1‐9) of VPLR. We observed ≥ minimal response in 68.4%, ≥ partial response (PR) in 54.4% and ≥ very good PR in 10.3% patients. Median progression‐free survival was 3.1 months (95% CI, 1.9‐3.9) and median overall survival (OS) was 8.1 months (CI, 6.2‐9.9). One‐hundred and sixteen (82.3%) patients received some therapy after VPLR; 71 (61.2%) received systemic chemotherapy, while 45 (38.8%) underwent SCT. Median OS for those who received SCT after VPLR was 15.1 months (CI, 10.3‐20.8). Age ≥ 60 years (hazard ratio [HR] 2.3 [CI, 1.4‐3.7]; P = 0.0008) and R‐ISS III stage (HR‐ 2.4 [CI, 1.3‐4.0]; P = 0.003) predicted shorter OS in patients receiving VPLR. VPLRs are effective in heavily pre‐treated RRMM. In fit patients, SCT can be used to consolidate the response to VPLR.