Hassan, Hamza

Introduction: High dose chemotherapy and autologous stem cell transplantation (ASCT) is one of the most effective therapies in light chain (AL) amyloidosis. It is associated with a high hematologic response rate and leads to durable remissions. High dose melphalan is the most frequently used conditioning chemotherapy, as has been used in multiple myeloma (MM). Melphalan dose is based on renal function, age, degree of cardiac involvement and patients' frailty and is predictive of outcomes. While studies that assessed the conditioning schedule have been conducted in MM, with variable results, no such studies were done in AL amyloidosis. Methods: In this retrospective study, we explored the impact of the conditioning schedule on post-transplant outcomes in a large multicenter study. Patients with AL amyloidosis who underwent ASCT for the primary diagnosis of AL amyloidosis between January 1, 2003, and December 31, 2020, were included in this study. Results: One thousand seven hundred and eighteen (n=1718) patients from 9 centers are included. The median age was 58 years, and 61% were male. Most patients had one (43%) or two (33%) involved organs, with the most involved organs were the kidneys (69%) followed by the heart (52%). Induction therapy was given to 52% of patients. The conditioning regimen was almost exclusively melphalan (99.2%), with 65% receiving full dose melphalan (≥170 mg/m 2). Melphalan was given over two days in most patients (80%). A rest day between conditioning and stem cell infusion was provided in 53% of patients, mostly in those who received melphalan on a single day rather than over 2 days (87% vs 44%, P<0.001). Post-transplant hematologic response was available for 1569 patients (91% of patients) and were assessed from baseline. Complete response (CR) and very good partial responses (VGPR) were achieved post-ASCT in 33.7% of patients each. Low dFLC-partial response (PR) was achieved in 2.7% and PR in 18% of patients. Altogether, satisfactory post-ASCT response (CR, VGPR, or low-dFLC PR combined) was achieved in 70% of patients. Compared to no induction, less than a PR to induction was associated with a lower probability of achieving satisfactory post-ASCT response, while PR or better to induction had higher chances of satisfactory post-ASCT response (65% vs 46% vs 84%, P<0.001). A single day of melphalan conditioning was associated with a higher probability of satisfactory post-ASCT response compared to two days of conditioning (82% vs 67%, P<0.001). Omitting a day of rest between conditioning and stem cell infusion was also associated with higher satisfactory post-ASCT response compared to having a rest day (76% vs 65%, P<0.001). The Table lists other predictors for a post-ASCT satisfactory hematologic response. In a nominal multivariate logistic regression analysis, independent predictors for higher post-ASCT satisfactory hematological response rate included: PR or better to induction therapy, female gender, kappa light chain isotype, lower dFLC at baseline, and kidney and liver involvement. In addition, full dose melphalan, conditioning given over a single day and having no rest day between conditioning and stem cell infusion were also associated with a higher likelihood of satisfactory post-ASCT response. Post-ASCT hematologic CR rate was higher in those receiving full dose conditioning (36% vs 28%, P<0.001), in those having no rest day (40% vs 28%, P<0.001) but not in those who received one day of conditioning versus two days (35% vs 33%, P=0.5). The rate of ICU admission was higher in those receiving no day rest (17.7% vs 12.6%), P=0.003) and among those who received reduced dose melphalan (18.1% vs 13.3%, P=0.008) but not based on number of conditioning days (P=0.56). Day 100 mortality was significantly higher in the no rest day group (5.6% vs 3.2%, P=0.01) and among those receiving reduced dose melphalan (6.8% vs 3.1%, P=0.004) compared to their counterparts, but not based on the number of days of conditioning (P=0.89). The median follow-up in the entire cohort was 104 months (95% CI 98-110). In a multivariate analysis for overall survival (OS), the conditioning dose but not the conditioning schedule was independently associated with OS. Conclusions: This study is the first to demonstrate the effect of melphalan conditioning schedule on post-transplant response. This study supports a single day melphalan conditioning in AL amyloidosis to improve post-ASCT response.

Introduction: BCMA-directed CAR-T and Bispecific T-cell engager (BiTE) therapies have shown remarkable overall response rates in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM). This has led to the approval of idecabtagene vicleucel, ciltacabtagene autoleucel and teclistamab by the FDA, EMA and other regulatory agencies. We performed a global survey on accessibility, practice patterns, and toxicity management of commercially available CAR-T and BiTE therapies. Methods: An online survey was completed by clinicians attending the International Myeloma Society's Immune Effector Cell Therapies in Multiple Myeloma Workshop, in-person or virtually, made available for 30 days after the meeting held in March 2023, Boston, MA. Results: 87 clinicians from 16 countries completed the survey, most practicing in an academic practice (86%) and in an urban environment (89%). Sixty-four percent of the respondents practice in North America followed by Europe (25.3%) including Germany, United Kingdom, Ireland, Italy, Netherlands, Spain, France, Greece, and Cyprus, and 6.9% from Asia and 3.4% from Australia. Seventy-seven percent reported CAR-T cell therapy was approved in their country with 44.8% treating 1-5 patients and 14.9% treating >5 patients per month; 67% reported BiTE therapy was approved in their country with 14.9% treating >5 patients per month. Of evaluable responses (n = 40), 62% administered CAR-T therapy inpatient and 15% administered CAR-T therapy outpatient ≥ 50% of the time. Length of time between decision to treat with CAR-T therapy to infusion was 6-12 weeks for 42% of responders and <6 weeks for only 20%. Most (75%) reported inpatient administration of BiTE therapy step-up dosing; 17.5% reported outpatient step-up dosing administered ≥ 50% of the time. Use of institutional or practice SOPs for CAR-T and BiTE therapy patient selection was reported by 85% and 58%, respectively, with the factors influencing SOP outlined in Table 1. Of available CAR-T therapies, 53% prefer cilta-cel and 23% reported CAR-T therapy preference depended most on patients' co-morbidities/frailty (89%), timing of next available apheresis (67%), age (56%), CNS disease (44%) and other factors. Maintenance therapy after CAR-T therapy was reportedly used by 25% and 5% of respondents in 1-10% and 11-50% of their patients, respectively, to “maintain level of response achieved” (50%) or “achieve a deeper level of response” (25%). About half (43%) of the respondents reported using an SOP or particular criteria for secondary Hemophagocytic Lympho-Histiocytosis/Macrophage Activation Syndrome/CAR-related-HLH (sHLH/MAS/CarHLH) management that varied between the use of ASTCT Working Group IEC associated HLH-like syndrome Criteria (47%) (Hines 2023), CARTOX HLH Criteria (24%) (Neelapu 2017) and HLH-2004 criteria (6%). Tocilizumab was used as cytokine release syndrome (CRS) prophylaxis only by one responder. Keppra neurologic prophylaxis was used by 47.5% and 15% of responders for CAR-T and BiTE therapy, respectively. Delayed neurotoxicity with CAR-T was reported in 1-5% of patients by 57.5% of responders and 6-10% of patients by 15% of responders; most common manifestations were other movement/neuromuscular disorder (62%), nerve palsy (55%), and Parkinsonism (45%). Infectious prophylaxis was used to protect against HSV (92.5%), PJP (90%), bacterial pathogens (55%), fungal pathogens (60%), and IVIG (77.5%). However, criteria for infectious prophylaxis use varies widely incorporating IgG levels, infectious history, CD4+ count, B-cell aplasia and cytopenias (48.1 - 88.9%). Most respondents (46.3 - 86.5%) reported completing an infectious work-up including CMV, EBV, Hep B/C, and HIV ( Table 2). Conclusions: Trends of CAR-T and BiTE therapy use and patterns of concurrent prophylactic and supportive care in MM vary widely among academic centers across the globe, demonstrating a need for further understanding of toxicity pathogenesis, toxicity management and consistent guidelines. This survey also demonstrates the great unmet need for access beyond urban centers among the international myeloma community. Prospective studies and claims data analysis should be utilized to evaluate the longitudinal cost of care, quality of life, duration of response and management of infectious disease, neurological or related complications of CAR-T and bispecific TCE therapies.

Introduction Amyloidosis is a rare disease and there are currently no FDA approved therapies for AL amyloidosis. Most of the therapeutic and disease data come from expert guidelines, consensus and retrospective review papers. There is a paucity of data specifically for relapsed/refractory AL amyloidosis (RRAL). We conducted this systematic review of clinical trials, retrospective and prospective cohort studies to evaluate patterns of relapse and therapeutic options for RRAL. Methods PubMed and Clinicaltrials.gov were searched for clinical trials, retrospective and prospective cohort studies on RRAL. Studies were selected according to PRISMA guidelines. Cross-trial comparison of included studies and meta-analysis could not be performed for a number of reasons but mainly due to a limited number of studies on one particular treatment regimen. Results From a total of 511 studies, 11 studies (n= 698 patients) met our inclusion criteria. Five were phase I/II clinical trials, five retrospective cohort studies, and one prospective cohort study. Most studies had less than 50 patients. The largest study, a retrospective cohort by Tandon et al. included 366 patients. Mean age was 61.2. Three studies reported 2 median prior lines of therapy (n= 22, 28, and 84 patients); two reported 3 median prior lines of therapy (n= 25 and 24) and 6 studies didn't specify this data. Prior treatment options included proteasome inhibitors (PI), most commonly bortezomib (n= 259), followed by melphalan (n=211), high dose melphalan and stem cell transplant (HDM/SCT [n= 207]) and IMiDs most commonly lenalidomide (n=154). Time to progression (TTP) from first-line treatment was reported in only 4 studies as 1 month, 5 months, 5 months and 34 months respectively. The study reporting a TTP of 34-months had 11 patients who received HDM/SCT as first line treatment. Three studies reported information about their criteria for initiation of subsequent treatment. Subsequent treatment was mostly a combination regimen with dexamethasone or an alkylating agent. The only agent evaluated as single agent was bortezomib in a phase I/II clinical trial by Reece et al. Therapeutic options for RRAL are PI (non-specific) based therapy (n= 145), lenalidomide (n= 105), bortezomib (n= 99), IMiD (non-specific) based therapy (n=83), melphalan based therapy (n= 33), carfilzomib (n=28), pomalidomide (n=27), ASCT (n= 25), daratumumab (n=25) and bendamustine (n=22). Efficacy: Hematologic responses were reported to be following: bortezomib + dexamethasone/melphalan (85%, n=17/20), daratumumab + dexamethasone (76%, n= 19/25), HDM/ASCT (73%, n= 8/11), single agent bortezomib (67%, n=23/34), carfilzomib ± dexamethasone (63%, n= 15/24), lenalidomide + dexamethasone (61%, n=51/84), bendamustine + dexamethasone (55%, 11/22) and pomalidomide + dexamethasone (50%, 12/24). Five of eleven studies reported organ responses which ranged from 18% to 23%. The studies which reported organ responses had evaluated the following agents: single agent bortezomib, carfilzomib ± dexamethasone, lenalidomide + dexamethasone, and bendamustine + dexamethasone. Best survival outcomes were seen with bortezomib with median overall survival (OS) 62 months. With bendamustine and dexamethasone (retrospective cohort study n=22) median OS was 31 months. With lenalidomide + dexamethasone (prospective cohort study n=24 ) median OS was 14 months. For the remaining studies, the median OS was either not reported or not reached at the time of presentation of data. Conclusion AL amyloidosis patients progressing after front line therapy show good responses with bortezomib (median overall survival of 62 months). Novel combinations using lenalidomide, pomalidomide, carfilzomib, daratumumab, and bendamustine show promising efficacy. Ongoing trials of daratumumab (AMYDARA trial) and ixazomib (TOURAMALINE-AL1) will bring further insight into therapeutic armamentarium for RRAL patients. After relapse, a salvage HDM/ASCT can be considered. Comparisons of regimen efficacy between studies are not practical because of multiple factors which include but are not limited to heterogenous nature of AL patients, small sample sizes, variable prior treatments, exposure to novel agents, observational study versus clinical trial and variable endpoints. Table Disclosures Anwer: Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; In-Cyte: Speakers Bureau.