Citations

e19532 Background: The diagnosis of amyloidosis requires histological confirmation of Congo-red (CR) deposits. The tissue source is preferably fat and/or bone marrow biopsy, but at times organ biopsy is required. Methods: We studied 612 patients with systemic light chain amyloidosis to characterize the tissues used to establish the diagnosis Results: The median number of tissue samples biopsied for CR staining was 3. Ninety-five percent of bone marrow (BM) biopsies were stained for CR, while 79% of patients had fat aspiration performed for CR staining. Overall, 76% of patients underwent both procedures. CR stain sensitivity was 69% in BM samples, 75% in fat aspiration and in 89% for both sources combined. CR stain sensitivity was 97-100% for heart, renal and liver biopsies. 42% of patients with renal involvement, 21% of patients with liver involvement and 13% of patients with heart involvement underwent organ biopsy, when a less invasive safer biopsy would have established the diagnosis. Predictors of need for organ biopsy were male sex, limited organ involvement and lack of fat aspiration (Table). Conclusions: Fat aspiration is underutilized for histologic confirmation of amyloidosis. Organ biopsies (particularly renal biopsies) were performed at a high rate, which represents a failure to recognize the disease (i.e. failure to screen with a light chain assay etc.). Early awareness of amyloidosis in the differential diagnosis of patients with organ dysfunction may lead to fewer unnecessary organ biopsies [Table: see text]

8049 Background: Complete response in AL is defined as normal FLC ratio with negative serum and urine immunofixation. It is not clear if high involved serum FLC (hIFLC) in a patient with normal ratio may contribute to ongoing amyloid formation and hence affect outcomes. Methods: Data of 1308 patients (pts) with systemic AL seen within 90 days of diagnosis, at Mayo Clinic between 2006-2015, was analyzed retrospectively. Among these, 369 pts had 2 consecutive normal FLC ratio values after 1st line treatment and form the study population. Log rank test was used to estimate survival differences. Results: Among these 369 pts, pts with hIFLC at 1streading of normal FLC ratio (hIFLC1; n=170; 46.1%) were compared to those who did not (n=199; 53.9%). At diagnosis, the median age [61.5 vs 60.8 years (y); p=0.2], proportion of males (62.4 vs 58.3%; p=0.4), percentage of pts with renal involvement (73.5 vs 64.8%; p=0.07), in mayo stage I / II / III / IV (32.9% / 23%/ 27.3% / 16.8% vs 43.6 %/ 22.9% / 18.1% / 15.4%; p=0.1), with bone marrow plasma cells >10% (24.2 vs 30%; p=0.2) and with presence of t(11; 14)(48.4 vs 60; p=0.08) was similar, while cardiac (67.5 vs 53.3%; p=0.006) and hepatic (18.2 vs 9.1%; p=0.01) involvement was higher in hIFLC1 group. The median follow-up from diagnosis was 6.1 y (95% CI; 5.6, 6.8). The median progression free survival (PFS) in pts who had hIFLC1 was lower than for those who did not; 2.6 y (95% CI; 1.9, 4.5) vs 5.2 y (95% CI; 4.6, 6.4), p<0.0001, as was the median overall survival [OS; 6.7 y (95% CI; 4.5, 8.3) vs not reached (NR), p<0.0001]. We performed a more stringent comparison for pts with 2 consecutive hIFLC values (hIFLC2; n=112; 30.4%) versus not (n=257; 69.6%). The median PFS (3.2 y; 95%CI; 2.2, 4.5 vs 5.6 y; 95% CI; 4.7, 7.1; p<0.0001) and OS (7.8 y; 95% CI; 6.4, NR vs NR; 95%CI; 9.5, NR; p<0.0001) were significantly reduced in pts with hIFLC2 versus not as well. A multivariate analysis confirmed an impact of hIFLC1 and hIFLC2 on PFS/OS independent of serum creatinine. Conclusions: In pts with systemic AL, persistent elevation of the involved FLC predicts for poor prognosis (independent of serum creatinine) even among those who achieved normal FLC ratio after 1st line treatment.

8048 Background: Organ response (OR) in AL is often delayed and difficult to predict early. Methods: We retrospectively analyzed 1308 patients (pts) with newly diagnosed AL from 2006 – 2015 to determine factors which could predict for OR. Results: Median age was 64 years (yr) and Mayo Stage was: 1 (22%); 2 (23%); 3 (25%); 4 (31%). Organ involvement was: cardiac (74%, n=932); renal (59%, n=738), liver (16%, n=205); gut (24%, n=310) and autonomic (12%, n=152). 59% (n=765) had > 1 organ involved, including 43% (n=567) with > 1 critical organ (heart, kidney, liver) involved. Treatment was: ASCT based (28%, n=330, N=1186), bortezomib based (24%, n=281), alkylator based (33%, n=392), others (5%, n=54) and none (10%). In evaluable pts, VGPR or better rates were: 53% at 6 months (m) (N=625), 72% at 12 m (N=465) and 57% overall (N=688). Table 1 lists OR at various time points. Complete OR in all involved critical organs was seen in: 51% (n=308, N=600), partial response (at least 1 OR when >1 organ involved) in 12% (n=73) and none in 37% (n=219). Complete OR was associated with better overall survival (OS) than partial or no OR (median OS: not reached vs 42 m vs 29 m; P <0.0001). In multivariate model the following variables at baseline or 1 yr mark were predictive of complete OR: lower Mayo Stage (p=0.01), fewer critical organs involved (p=0.007), higher baseline GFR (p=0.03), female sex (Complete OR 60% vs 47%; p=0.04) and VGPR at 1 yr (Complete OR 70% vs. 36%; p <0.0001). Other factors included in the model were age (p=0.9), bilirubin (p=0.1) and transplant (p=0.2). All aforementioned factors were significant in univariate analysis. Conclusions: Achievement of response in all involved critical organs is associated with better survival in AL pts than partial or no OR. Various baseline factors and VGPR at 1 yr can predict for achieving complete OR, with 70% pts who achieve VGPR at 1 yr having a complete OR. [Table: see text]

8047 Background: Presence of CPCs by six color MFC is associated with worse outcomes in multiple myeloma (MM). Using a slide based immunofluorescence assay, CPCs are associated with worse prognosis in AL, but outcomes with MFC are not known. Methods: We retrospectively analyzed 154 patients (pts) from Jan 2008 – Dec 2015 with AL who had CPCs analyzed by MFC at diagnosis. Results: CPCs were present in 42% pts (n = 64, median = 88 per 150,000 events, range 6-17844). Table 1 lists baseline characteristics, treatment and response. In univariate analysis, bone marrow (BM) plasma cells > 15% (p<0.0001), dFLC > 60 mg/dL (p=0.02) and presence of active MM (p=0.0004) were associated with detectable CPCs. In multivariate (MV) model, only BM plasma cells > 15% predicted for presence of CPCs (p=0.02). There was no difference in hematologic or organ response in the 2 groups. Median follow up was 43 months (m). Pts with detectable CPCs had worse survival than those without detectable CPCs (90 m vs. 98 m, p=0.0004). In MV analysis model with Mayo Stage and detectable CPCs, presence of CPCs at diagnosis was independently associated with poor survival (CPCs p= 0.02, Mayo Stage p < 0.0001). Conclusions: Presence of detectable CPCs is an independent adverse prognostic factor for survival in AL. Comparatively fewer pts with detectable CPCs underwent early ASCT, which may reflect a more aggressive disease presentation. [Table: see text]

8038 Background: Daratumumab-based Combination Therapies (DCT) with bortezomib (V)/ lenalidomide (R)/ pomalidomide (P) and dexamethasone (d) showed exceptional activity in RRMM in trials. Experience outside of trials since the approval of Daratumumab (D) in 2015 is limited. Methods: RRMM pts seen at Mayo Clinic, MN from 12/2015 -12/2016 were reviewed. Pts who received ≥ 1cycle of DCT were included. Time-to-event analyses were done from date of starting DCT. Common terminology criteria for adverse events v4.0 were used to grade toxicities. Results: Of 130 pts, 59% were males and median age at DCT initiation was 67 (43-93) years, ECOG performance score was ≥2 in 29%. Pts were classified as mSMART high (22%), intermediate (22%) or standard (56%) risk. Median time from diagnosis to initiation of DCT was 51.3 (5-156) months (m), and median number of prior therapies was 4 (1-14). 14% of pts were refractory to prior D monotherapy. Fifty-three (41%), 34 (26%) and 25 (19%) received DPd, DRd and DVd respectively. Eighteen (14%) pts received ‘other’ DCT. Median time to first response (≥ PR) was 3.1 m (95% CI 2.1-4.6). Overall response rate was 46%, [CR-2%, VGPR-18%, PR-26%]. Minimal response was seen in 17%, with clinical benefit rate of 62%. Median estimated follow up from initiation of DCT was 5.5 m (CI 4.2-6.1). The median duration of response was 6.1 m [CI 5.1- not reached (NR)]. Median progression free survival (PFS) was 5.5 m (CI 4.1-7.8) and median time to next therapy (TTNT) was 5.9 m (CI 4.6-9.4). Median PFS for DPd, DRd, DVd and other DCTs were 4.6 (CI 2.7-NR), 7.8 (CI 5-NR), 3.9 (CI 2.1-NR) and 3.9 (CI 2.8-8.2) m, respectively (p = 0.3). Median PFS for quadruple refractory (n = 28) MM was 2.8 m (CI 2.2-5.3) vs 5.9 m (CI 4.9-NR) for the rest (p < 0.01). Median overall survival (OS) from DCT was NR (CI 11.4-NR). Grade 3 or higher hematological toxicities were seen in 42% of pts. Other toxicities included infections (37%), fatigue (31%), infusion reactions (16%) and diarrhea (10%). Conclusions: DCT are effective in RRMM, but the PFS remains short particularly in quadruple refractory pts, reflecting the challenges encountered in managing heavily-pretreated, and often less fit patients, in routine practice.

8032 Background: Human adipocytes can contribute directly to the in vitro growth and progression of multiple myeloma (MM) cell lines. Clinically, an elevated body mass index (BMI) has been associated with an increased risk of MGUS and a shorter time to progression (TTP) of MGUS to MM. However, the impact of BMI on the risk of early progression to MM from a more advanced plasma cell disorder such as smoldering MM (SMM) remains unknown. Methods: This study included patients (pts) with a known or new diagnosis of SMM evaluated at the Mayo Clinic, Rochester from January 2000-December 2010. Pts were classified based on their BMI as: normal (< 25) and elevated (>/= 25) BMI. Progression to symptomatic MM was defined by the development of hypercalcemia, renal insufficiency, anemia or lytic bone lesions. Results: There were 306 pts with a diagnosis of SMM who were included in this analysis. The median follow up was 106 months. There were 203 (66%) pts who progressed to symptomatic MM at last follow up. The median BMI of the group was 27.5 (Range: 17.2 – 56.4). There were 228 (75%) pts with an elevated BMI. There were 76 (28%) pts who had myeloma defining events (MDEs) such as a serum free light chain ratio > 100 or > 60% clonal bone marrow plasma cells at initial evaluation. MDEs were present in 17% and 33% of pts with a normal and elevated BMI respectively (P = 0.011). The median TTP of SMM to MM in pts with a normal and elevated BMI was 64 and 36 months respectively (P = 0.0006). The 2-year progression rate of SMM to symptomatic MM in pts with a normal and elevated BMI was 16% and 42% respectively (P < 0.0001). Upon limiting the analysis to only SMM pts without MDEs at initial evaluation (N =187), the 2-year progression rate to symptomatic MM with a normal and elevated BMI was 15% and 33% respectively (P = 0.013). In a multivariable model, only elevated BMI (P = 0.004) and increasing clonal bone marrow plasma cells (P = 0.001) was statistically significant in predicting for a 2-year progression to MM. Conclusions: SMM pts with an elevated BMI appear to have a higher risk of early progression to MM than those with a normal BMI. This study provides evidence of a potentially modifiable risk factor for the progression of SMM to MM and warrants confirmation in larger studies.

8020 Background: Circulating plasma cells (CPCs) at diagnosis, prior to transplant and at relapse have a negative prognostic impact on survival in multiple myeloma (MM). However, the impact of changes in CPCs along the course of illness has not been defined. Methods: We evaluated 247 patients with newly diagnosed MM (NDMM) undergoing early autologous stem cell transplantation (ASCT) in the era of novel agents (2007 to 2015), who had serial evaluation of CPCs at diagnosis and pre-ASCT by 6-color flow cytometry. Results: The median age at transplant was 62 years.A total of 117 (47%) patients had no detectable CPCs at both time points (CPC-/-), 82 (33%) had CPCs at diagnosis followed by complete eradication after induction therapy (CPC+/-) and 48 (19%) had detectable clonal CPCs at transplant, with persistence of cells (CPC+/+; n=45) or emergence of new CPCs (CPC-/+; n=3) after induction. The incidence of t(11;14) by iFISH was lower in the CPC-/- group (19%) compared to CPC+/- (29%) and CPC +/+ or -/+ (39%) groups ( p=0.033). Conversely, the incidence of hyperdiploidy was significantly higher in patients with CPC-/-, compared to those with CPC+/- and CPC+/+ or -/+ (64%, 44% and 39% respectively; p=0.005). The rate of post-ASCT stringent complete response was 32% in the CPC-/- group, 30% in CPC+/- group and 12% in CPC+/+ or -/+ group ( p=0.018). At a median follow-up of 58 months from ASCT, the median progression-free survival (PFS) from transplant in the 3 respective groups was 30, 24 and 14 months and the 5-year overall survival (OS) rates were 83%, 70% and 43% ( p<0.001 for both comparisons). On a multivariate analysis, using CPC-/- group as the comparator, PFS and OS was significantly inferior in CPC+/- (RR 1.6; p=0.020 and RR 2.7; p=0.008 for PFS and OS respectively) and CPC +/+ or -/+ groups (RR 2.9; p<0.001 and RR 5.8; p<0.001 for PFS and OS respectively). Conclusions: Clonal CPCs are detectable in more than 50% of newly diagnosed MM patients undergoing upfront ASCT. Monitoring for CPCs before initiation of induction therapy and before ASCT by 6-color flow cytometry is highly predictive of outcome in NDMM and should be incorporated into prospective clinical trials.