Khouri, Jack

Patients with plasma cell leukemia (PCL) are generally excluded from pivotal T-cell redirecting bispecific antibody (BsAb) trials. We evaluated real-world outcomes in a multicenter retrospective study of 122 patients with primary or secondary PCL across 15 academic centers, categorized as 'active' (≥5% circulating plasma cells within 30 days of BsAb initiation) or 'historical'. In a heavily pretreated population, patients received teclistamab (37%), elranatamab (11%), talquetamab as a line of therapy (Tal LOT, 42%), or talquetamab as bridging therapy to CAR-T (Tal Bridge, 11%). Cytokine release syndrome (CRS) was grade 1-2 in 56% and grade 3-4 in 4%, whereas neurotoxicity was grade 1-2 in 16% and grade 3-4 in 5%. Among 110 evaluable patients, the overall response rate (ORR) was 55%, including 61% with Tal LOT, 58% with Tal Bridge, 46% with elranatamab, and 33% with teclistamab. With a median follow-up of 8.3 months, talquetamab demonstrated superior survival. Tal LOT showed a median progression-free survival (mPFS) of 5.5 months and a median overall survival (mOS) of 11.5 months, and both were unreached in the Tal Bridge cohort. In contrast, teclistamab and elranatamab showed a mPFS of 1.2 and 1.6 months and mOS of 8.1 and 3.6 months, respectively (P=0.007, P=0.023). In active PCL, Tal LOT achieved mPFS/mOS of 6.9/12.2 months versus 0.7/1.4 months with teclistamab and 1.0/3.1 months with elranatamab, respectively (P<0.001, P=0.002). Multivariable analysis associated active PCL with worse survival and Tal LOT with improved outcomes. BsAbs were safe in PCL, with talquetamab showing superior outcomes compared with BCMA-directed BsAbs.

Summary Functional high‐risk (FHR) multiple myeloma (FHRMM) is often defined as progression within 12–24 months of front‐line autologous hematopoietic stem cell transplantation (AHSCT). For patients with early progression after suboptimal front‐line therapies, it is challenging to assign the disease progression to a true FHR phenotype versus less effective front‐line therapy. In this study, we combined data from three Center for International Blood and Marrow Transplant Research studies (MM18‐02, MM19‐01 and MM20‐03). We included patients who received front‐line AHSCT between 2008 and 2018 and had progression <12 (FHR12, n = 465), <18 (FHR18, n = 672) or <24 months (FHR24, n = 853) after AHSCT. We classified induction therapy as standard lenalidomide‐containing triplets (bortezomib, lenalidomide, dexamethasone [VRD]/carfilzomib, lenalidomide, dexamethasone [KRD]) versus other (bortezomib, thalidomide, dexamethasone [VTD]/bortezomib, cyclophosphamide, dexamethasone [VCD]/bortezomib, dexamethasone [VD]/lenalidomide, dexamethasone [RD]) and studied the impact of front‐line therapy on post‐FHR overall survival (OS). In the FHR12 cohort (follow‐up 48 months), the OS after VRD/KRD ( n = 238) was 21 versus 17 months with other regimens ( n = 227, hazard ratio [HR] = 1.2, 95% confidence interval [CI]: 0.6–1.06). In a multivariable model, the HR for OS was 0.94 (95% CI: 0.7–1.3, p = 0.69) for VRD/KRD versus other regimens. There was no significant interaction between type of first‐line (1L) therapy and time from 1L AHSCT to first relapse in predicting OS. Similar results were seen for FHR18 and FHR24. FHRMM remains a negative prognostic factor irrespective of front‐line therapy and warrants consideration of T‐cell engagers' second‐line therapy.

Abstract In this systematic review, we aimed to assess the sensitivity of serum immunofixation (SIFE), urine immunofixation (UIFE), and serum free light chain (sFLC) in detecting plasma cell dyscrasia associated with light chain (AL) amyloidosis. We searched the literature using PubMed, Embase, and CENTRAL databases since inception through March 2024. We included studies reporting the diagnostic accuracy of immunofixation and/or sFLC in patients with AL amyloidosis. We used the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach to assess the certainty of the evidence and QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) to assess the risk of bias. After deduplication, 29 237 records were screened, and 44 studies (n = 18 071) were included. For the meta-analysis, 28 studies reported sensitivity for SIFE (n = 3390), 24 studies for UIFE (n = 2830), 19 studies for SIFE and UIFE (n = 2819), 21 studies for sFLC ratio (n = 3678), 6 studies for SIFE and sFLC ratio (n = 372), 3 studies for UIFE and sFLC ratio (n = 242), and 10 studies for all 3 tests (n = 1430). Pooled sensitivities were as follows: SIFE, 0.68 (95% confidence interval [CI], 0.62-0.73); UIFE, 0.77 (95% CI, 0.72-0.81); SIFE and UIFE, 0.89 (95% CI, 0.84-0.93); and sFLC ratio, 0.82 (95% CI, 0.78-0.86). When SIFE, UIFE, and sFLC ratio were combined, the sensitivity reached 0.99 (95% CI, 0.96-1.00). The high sensitivity of combining SIFE, UIFE, and sFLC ratio supports their use as a reliable initial testing strategy to raise suspicion for AL amyloidosis and guide decisions regarding future diagnostic modalities.

Abstract Systemic amyloidosis is a rare, multisystem disorder that is often challenging to diagnose due to vague and nonspecific symptoms that frequently overlap with other disorders. By the time patients are diagnosed, irreversible organ impairment from amyloid deposition occurrs, contributing to substantial morbidity and mortality. Although developing the American Society of Hematology (ASH) guidelines on systemic amyloidosis, we identified a critical knowledge gap in the recognition of the clinical presentation of its most common subtypes. Therefore, we conducted a scoping review of 117 studies following PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) guidelines to identify clinical “red flags” for light chain (AL) and transthyretin (ATTR; wild-type [ATTRwt] and hereditary [ATTRv]) amyloidosis. Studies were identified from the comprehensive systematic review through the ASH amyloidosis diagnosis guideline panel, data mining, and gray literature review. Data were extracted and synthesized by systems to characterize the earliest and most frequently overlooked clinical red flags for the different types of amyloidosis. Shortness of breath and fatigue, the earliest symptoms of AL amyloidosis, contrast with the carpal tunnel syndrome occurring years before ATTRwt cardiac amyloidosis is diagnosed. Weight loss, unexplained abdominal pain, and early satiety were overlooked red flags for AL amyloidosis, compared to the preceding arrhythmias often missed in evaluation for ATTRwt amyloidosis. Sensory loss was the predominant neuropathic presentation for AL amyloidosis compared to the painful length-dependent neuropathy of ATTRv amyloidosis. Awareness of the early symptoms and distinct patterns across subtypes can enhance cross-specialty awareness and support earlier diagnosis and intervention of AL and ATTR amyloidosis.

Background Light chain (AL) amyloidosis is a rare disease caused by the misfolding of immunoglobulin light chains produced by a plasma cell dyscrasia. Patients can present with involvement of many organs, including the heart, kidneys, liver, nerves, and other sites, resulting in a high symptom burden. Timely and accurate diagnosis is important to prevent organ failure and improve patient survival. Objective These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients and clinicians in the timely and effective diagnosis of AL amyloidosis. Methods ASH formed a multidisciplinary guideline panel that included 22 individuals representing various medical specialties (academic and community hematology, nephrology, neurology, cardiology, internal medicine, and pathology) as well as 1 patient representative. The group was balanced to minimize potential bias from conflicts of interest. The University of Kansas Medical Center supported the guideline development process, including updating or performing systematic evidence reviews (up to 6 March 2023). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment. Results The panel agreed on 12 recommendations. Conclusions The use of serum immunofixation, urine immunofixation, and serum free light chains enhances the clinical suspicion of AL amyloidosis. The diagnosis of AL amyloidosis can be made effectively through surrogate biopsies, which require both a bone marrow biopsy and fat-pad sampling; however, target organ biopsies may be favored in certain clinical situations.

Abstract Introduction: Cilta-cel is a BCMA-directed CAR T-cell therapy that has shown remarkable efficacy in patients with RRMM. As real-world (RW) experience with cilta-cel continues to expand, and with the recent FDA guidance reducing the recommended proximity to the CAR T center from four to two weeks post-infusion, there is growing interest in identifying patients at low risk for severe early complications who may be safely managed in the outpatient setting and potentially ‘discharged’ home earlier. Methods Data were collected from 769 patients with RRMM treated with cilta-cel at 15 institutions in the U.S. via the Multiple Myeloma Immunotherapy Consortium.Logistic regression was used to identify predictors of patients who could be managed in the outpatient setting (low-risk group). Based on expert consensus within the Consortium, low-risk patients were defined as: grade ≤1 CRS, no ICANS, and no IEC-HS. The remaining patients were categorized as high-risk. We evaluated baseline characteristics with missingness &lt; 20% as predictors, including age, sex, race, and ethnicity, ECOG performance status (PS) at time of lymphodepletion (LD), extramedullary disease, bone marrow plasma cell (BMPC) percentage, high-risk cytogenetics, bridging therapy including response, penta-refractory status, number of prior lines of therapy, prior anti-BCMA therapy, baseline C-reactive protein (CRP), and baseline ferritin. The cohort was restricted to patients with complete data on all predictors (n=455) and split into a training and testing cohort (80/20 split, n=364/91). Bidirectional stepwise regression was used to build the predictive model using variables with significance of p&lt;0.15 selected for entry. The best model was selected based on the AIC (Akaike Information Criterion) and a significance level of p&lt;0.05. Results Among the 455 patients with complete data included in the final model, 290 (64%) were categorized as low-risk and 165 (36%) as high-risk. Compared to the low-risk group, high-risk patients were more likely to have an ECOG PS ≥2 at time of LD (20% vs 9%, p&lt;0.001), high-risk cytogenetics (47% vs 35%, p=0.009), and penta-refractory disease status (34% vs 24%, p=0.031). High-risk patients also had a higher median BMPC percentage (15% vs 5%, p&lt;0.001), and higher baseline pre-LD CRP and ferritin. Overall response rates were high, at 95% vs 90% (p=0.047) for the low vs high risk groups, with complete response or better achieved in 73% vs 66% of patients, respectively (p=0.14). With a median follow-up of approximately 11 months, median progression-free survival was not reached (95% CI: 27-NA) in the low-risk group and 18.2 months (95% CI: 13.1-NA) in the high-risk group. In terms of safety, non-ICANS neurotoxicity (NINT) occurred less frequently in the low-risk group (6.6% vs 13%, p=0.015). Specifically, Parkinsonism was observed in 1.7% vs 6.1% (p=0.013), and cranial nerve palsy in 4.5% vs 5.5% (p=0.7), respectively. Non-relapse mortality (NRM) was lower in the low-risk group (4.2%) compared to the high-risk group (14%; p &lt; 0.001). The most common causes of NRM in the low- and high-risk groups were acute toxicities (0% vs 36%, including CRS, IEC-HS, and ICANS), delayed toxicities (0% vs 8%, including colitis, NINT, and Parkinsonism), infections (50% vs 48%), and other unrelated causes (50% vs 8%). The best model to predict low-risk patients that could be managed in the outpatient settingincluded BMPC percentage and ECOG PS at LD. In the training cohort, patients with a higher pre-LD BMPC percentage and an ECOG PS ³2 were less likely to be in the low-risk group(OR per 1-unit change in BMPC percentage = 0.99, 95% CI=0.98-0.99, p&lt;0.001 and OR for ECOG PS 2-4 = 0.38, 95% CI=0.20-0.72, p=0.003). The AUC for this model was 0.663 in the training cohort and 0.659 in the testing cohort. Conclusion In this large, multi-institutional cohort of patients with RRMM treated with cilta-cel, we identified clinical factors associated with lower risk for early severe toxicities, supporting outpatient administration and the potential for earlier discharge in selected patients, particularly those who are fit and have low disease burden. Our findings provide a practical framework to guide risk stratification and outpatient CAR T management strategies, particularly in light of evolving regulatory guidance and growing RW experience with cilta-cel.

Abstract Introduction: Ciltacabtagene autoleucel (cilta-cel) is a highly effective BCMA-redirected CAR T-cell therapy for RRMM. While the pivotal CARTITUDE-1 trial established a target dose of 0.75 x 10^6 CAR+ viable T-cells/kg, the approved cell dose is 0.5-1.0 x 10^6 and the optimal dosing strategy to balance efficacy and toxicity remains unclear. This question is of interest given that a dose-response association has been demonstrated for idecabtagene vicleucel (a related BCMA-directed CAR T product). It has also been hypothesized that lower doses of cilta-cel may be associated with reduced toxicity. This study aims to evaluate the association between cilta-cel dose and key efficacy and toxicity outcomes using a large, real-world dataset from the US Multiple Myeloma Immunotherapy Consortium. Methods: We conducted a multicenter, retrospective analysis of 751 RRMM patients treated with commercial cilta-cel across 15 US academic centers. The administered cilta-cel dose (million cells/kg) was categorized into four groups: low (&lt;0.5), standard-low (0.5 to &lt;0.6), standard (0.6 to &lt;0.8), and standard-high (0.8 to 1.0). We compared incidence rates of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), delayed neurotoxicity (DNT), and immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) across these dose categories using logistic regression. Best response rates and progression-free survival (PFS), estimated using the Kaplan-Meier method, were also compared, with differences assessed using the log-rank test for the latter. Results presented are derived from multivariable models adjusting for extramedullary disease, ECOG status, penta-refractory disease and receipt of bridging therapy. Results: Among 751 infused patients, the dose distribution was: &lt;0.5 (n=33), 0.5 to &lt;0.6 (n=131), 0.6 to &lt;0.8 (n=550), and 0.8 to 1.0 (n=37). The four dose groups were well-balanced in terms of baseline patient and disease characteristics, including age, high-risk cytogenetics, and extramedullary disease, with the exception of t(14;16), which was more common in the standard-low and standard dose groups (p=0.006). There were no statistically significant differences in the rates of any grade CRS (p=0.11), any grade ICANS (p=0.84), grade ≥3 ICANS (p=0.36), duration of CRS (p=0.18) or ICANS (p=0.64), or IEC-HS (p=0.16) across the four dose categories. Time to onset of CRS was shorter for the standard-high dose compared to the low dose (6 days vs. 8 days; p=0.08). Importantly, there was no significant difference in the rate of DNT (3.0%, 9.2%, 8.8%, 5.4%; p=0.24). Similarly, there was no significant difference in overall response rates (97%, 96%, 96%, 88%; p=0.50) or complete response rates (75%, 65%, 75%, 66%; p=0.10) by dose. The median follow-up was 12.3 months (IQR: 6.9, 20.5). For patients who received a standard-low dose (0.5, 0.6), the median PFS was 17.5 (IQR: 13.5, NR) months. For the standard dose range of (0.6, 0.8), the median PFS was 28.7 (95% CI: 19.8, NR) months, while the median PFS for the standard-high dose (0.8, 1.0) was not reached. For the low dose range of &lt;0.5, the median follow up was only 8.7 months, which did not allow reliable estimation of the median PFS. While the overall difference in PFS among the groups did not reach statistical significance by the log rank test, there was a clear trend toward improved PFS with higher cell doses in the multivariable model, with outcomes clearly ordered in the same direction as the cell dose categories. A similar trend was also evident in the rates of 12-month PFS which showed an improvement with increasing dose (62% ,67%, 73%, 80%). Conclusions: In this large, real-world cohort of RRMM patients treated with cilta-cel, a lower cell dose was not associated with reduced incidence or severity of CRS, ICANS, DNT, or IEC-HS. Conversely, a dose-response correlation with PFS was observed, with higher doses trending toward longer median and 12-month PFS. It remains unknown if a lower cell dose in the commercial setting reflects poor T cell quality, yet these findings suggest that dose reduction of cilta-cel may not be an effective strategy to mitigate toxicities and might be associated with a trend toward lower efficacy. Therefore, the standard target dose should be utilized to maximize patient outcomes and further prospective dose exploration is warranted.

Abstract Introduction: The GPRC5D-directed bispecific antibody (BsAb) Talquetamab (Talq) has shown promising results for patients (pts) with relapsed/refractory multiple myeloma (RRMM) in the MonumenTAL-1 clinical trial (Chari et al. NEJM 2022). However, there are limited data on the use of Talq in the real-world setting. Methods: All pts with RRMM who started Talq between 8/2023-3/2025 across 15 US academic centers were included. High-risk cytogenetic abnormalities (HRCA) were defined as del(17p), t(4;14), t(14;16) and/or gain/amplification 1q21. Time-to-event analyses were estimated using the Kaplan-Meier method. Toxicities including CRS and ICANS were graded using CTCAE v5.0 or ASTCT criteria. Results: A total of 484 pts were included, with a median age of 65 years (range 35-89), and 83 pts (17%) were aged ≥75 years. 20% of pts were black. 21% had baseline CrCl&lt;40, 65% had HRCA and 29% had &gt;1 HRCA (i.e Ultra high-risk MM). The median number of prior lines of therapy was 6 (IQR 4, 8). 50% were penta-refractory, 69% received at least one prior BCMA-directed therapy (46% CART; 32% BsAb). Prior to initiation of Talq, 11 pts (2%) had CNS MM, 29 (6%) had PCL and 126 (26%) had true extramedullary disease (EMD). 70% would have been ineligible for the MonumenTAL-1 trial. For most pts (n=405; 84%) the dosing strategy from Cycle 2 was 0.8 mg/kg every 2 weeks. and the 0.4 mg/Kg weekly dosing was used in 28 patients (6%). In 6% of pts, an additional drug was added to Talq, mostly pomalidomide (n=20) or daratumumab (n=10). 101 pts (21%) received Talq as bridging for CART. Median duration of Talq treatment was 102 days. 62% developed CRS (Grade ≥3, 2%; including one Grade 5 event). 15% developed ICANS (Grades 3-4, 4%). Steroids were used in 213 patients (44%), tocilizumab in 145 (30%) and anakinra in 9 (2%). 22 patients (5%) required ICU stay during the first cycle, for a median of 6 days (range 1-31). A total of 200 pts (41%) had infections (median 1 infection each, range 1-6), including 99 (20%) with bacterial infections, 113 (23%) viral infections and 21 (4%) fungal infections. IVIG was used in 261 pts (54%). 79% of patients (n=384) developed Talq-related oral toxicity, 55% (n=269) skin toxicity and 199 (41%) nail toxicity. 157 patients died after a median follow up of 11.5 months (mos), and the leading causes of death were MM progression (n=120) and infection (n=10). 8 pts (1.7%) developed invasive second primary malignancies. The ORR was 73%, including 46% ≥VGPR. The median PFS (mPFS) for the entire cohort was 7.8 mos (95% CI 6.9-9.4) and the 12 months PFS rate was 39%. The median OS had not been reached and the 12 months OS rate was 63%. For pts who would have been eligible for MonumenTAL-1, the mPFS was 12.2 mos (95% CI 9.7 – not reached (NR); for trial-ineligible pts, the mPFS was 6.9 mos (5.8 – 8.0; p=0.003). For BCMA-naive pts, the mPFS was 15.7 mos (11.8-NR); for BCMA-exposed pts, the mPFS was 6.8 mos (6.0-7.8; p=0.0002). For patients who received Talq as bridging prior to CART, the median PFS was NR (14.1 – NR); for those who did not receive Talq as bridging the mPFS was 6.5 mos (5.3-7.6; p&lt;0.0001). In multivariable analyses, worse OS and PFS were associated with trial ineligibility [(HR 1.38, 95% CI 1.03-1.86; p=0.03) and (2.33, 1.31-4.14; p=0.004)], BMI&lt;30 [(1.42,1.06-1.89; p=0.02) and (1.50, 1.01-2.22; p=0.045)] and true EMD at baseline [(1.95, 1.49-2.56; p&lt;0.001) and (1.65, 1.16-2.36; p=0.005). On the other hand, use of Talq as bridging to CART was associated with better PFS (0.27, 0.17-0.43; p&lt;0.001) and OS (0.13, 0.05-2.56; p&lt;0.001). Ultra high-risk MM (1.40, 1.06-1.84; p=0.02) and baseline albumin &lt;3 (1.68, 1.18-2.37; p=0.004) were associated with worse PFS; ECOG ≥2 (1.68, 1.18-2.40; p=0.004), and baseline Plt&lt;50K (2.14, 1.48-3.10; p&lt;0.0001) was associated with worse OS. Conclusions: In this large real-world analysis of 484 Talq recipients, the ORR was comparable to MonumenTAL-1 but the median PFS was shorter. This likely reflects differences in patient selection, with 70% of patients in our cohort being trial-ineligible. Patients who received Talq as pre-CAR-T bridging had superior survival outcomes. Rates of toxicities were similar to MonumenTAL-1, including &gt;70% of patients developing dysgeusia.