Citations

Abstract Background: TP53-mutated (TP53mut) myeloid neoplasms (MN) are a biologically and clinically distinct subgroup of blood cancers associated with extremely poor outcomes and limited response to conventional therapies. In some patients, MN are preceded by clonal cytopenia of undetermined significance (CCUS). Prior cytotoxic exposure (treatment related, TR) is an independent predictor for survival in CCUS (Li et al, Blood Adv. 2024). As TP53mut CCUS and MN are enriched in TR cases, the interaction between cytotoxic exposure and TP53mut status on the risk of progression and survival remains unclear. Methods: Adult patients with CCUS who were evaluated at the Mayo Clinic or South Australian myelodysplastic syndrome (MDS) Registry (Adelaide, Australia) were included. CCUS and MDS were defined according to the 5th edition of the WHO classification for MN (Khoury et al, 2022), except for the exclusion of cases harboring MDS-defining cytogenetics. Next-generation sequencing was performed using a targeted panel covering genes commonly mutated in MN. In cases with >1 TP53mut, VAFs were summed. Survival outcomes were assessed by Kaplan-Meier with log-rank testing. Univariate and multivariate analyses were estimated using Cox proportional hazards regression. Results: Of 320 CCUS cases, 50 (15.6%) harbored TP53mut (TP53mut CCUS), whereas 270 (84.4%) were wild-type (TP53wt CCUS). Median age at diagnosis was 71 years (range 16-99). TP53mut CCUS had a greater proportion of females (60% vs 33.7%, p<0.001) and TR (66% vs 23%, p<0.001) compared to TP53wt. Hematologic parameters including hemoglobin, red cell distribution width, mean corpuscular volume, white blood count, absolute neutrophil count, platelets, and bone marrow blasts were comparable between the two groups. Almost all TP53mut (n=48, 96%) were located in the DNA-binding domain and the median variant allele frequency (VAF) was 9% (range 2-46%). Five (10%) cases harbored 2 TP53mut. The distribution of TP53mut VAF among patients was as follows: ≤2.5% (n=2), 2.5-5% (n=10), 5-10% (n=19), 10-20% (n=11), and ≥20% (n=7). The proportion of cases with cytogenetic abnormalities was smaller in TP53mut compared to TP53wt CCUS(12% vs 25.9%, p=0.035). Both cohorts had a comparable median number of mutations: 2 (range 0-7) in TP53mut and 2 (range 0-5) in TP53wt. The most common co-mutations in TP53mut CCUS were TET2 (n=8, 17.8%), PPMD1 (n=7, 15.6%), DNMT3A (n=6, 13.3%), ASXL1 (n=6, 13.3%), and SRSF2 (n=4, 8.9%). At last follow up, the rate of progression was comparable between TP53mut and TP53wt CCUS (12% vs 22%, p=0.13). Median time to MN progression was not reached in TP53mut and 6.25 months in TP53wt CCUS (p=0.5197). A significantly higher proportion of TP53mut cases acquired complex cytogenetics compared to TP53wt cases (33% vs 2%, p=0.024) at MN progression. Of 20 deaths observed in the TP53mut cohort, non-myeloid hematologic malignancies (n=6, 30%), infections (n=5, 25%), and TP53mut MN (n=4, 20%) were the 3 most common causes. With a median follow-up of 4 years (IQR 1.2-4.8), median OS was longer in de novo (dn) cases (8.7 years for dn TP53wt; not reached for dn TP53mut) and shorter in TR cases (3.3 years for TR TP53wt; 4.8 years for TR TP53mut). Notably, TP53mut showed no independent prognostic impact in the entire cohort, or when stratified by TR vs dn CCUS. On multivariate analysis that included TP53mut status, factors independently associated with inferior OS included prior therapy (HR 2.21, 95% CI 1.41-3.45, p<0.001), anemia (HR 4.1, 95% CI 1.88-8.99, p<0.001), and thrombocytopenia (HR 2.38, 95% CI 1.43-3.95, p<0.001). Similarly, TR CCUS (HR 1.6, 95% CI 1.06-2.4, p=0.03) and anemia (HR 2.15, 95% CI 1.25-3.7, p=0.006) were independently associated with inferior progression free survival. Conclusion: TP53 mut in CCUS did not independently predict inferior survival or increase leukemic transformation. While TP53mut CCUS were less likely to harbor cytogenetic abnormalities at diagnosis, significantly more cases harbored genomic instability at leukemic transformation. The poor outcomes attributed to TP53mut CCUS were driven by prior cytotoxic exposure, cytopenia – particularly anemia, and non-leukemic causes of death. These findings suggest risk stratification in CCUS should prioritize clinical context over TP53mut status alone.

Abstract Introduction: Although therapies targeting Bruton Tyrosine Kinase (BTK), either as monotherapy or in combination have revolutionized the treatment in chronic lymphocytic leukemia (CLL), the disease remains incurable. Continuous treatment with these agents frequently leads to the development of resistance and disease progression, mostly associated with mutations in BTK or PLCG2. However, a significant fraction of BTKi-resistant patients does not harbor mutations in these genes, revealing that multiple distinct mechanisms of resistance can independently develop in these patient cohorts. Identifying novel molecular pathways associated with drug resistance in the relapsed/refractory (RR) setting of CLL requires more exploration. Materials and Methods: Using the Mayo Clinic CLL Database and tissue bank, we identified 30 RR patients, who had had disease progressionon a BTKi. The median lines of prior therapies were four. The median age at start of treatment was 57.9 (range, 36-78), 77% were male. Rai stage at diagnosis was 0 in 10% of patients, stage I in 37%, stage II in 20%, stage III in 6%, and stage IV in 27%. IGHV unmutated was observed in 87% of cases. Five patients subsequently evolved to Richter's Transformation (RT). A total of 64 blood samples were collected at different timepoints: baseline (before BTKi therapy), during treatment and at disease progression from BTKi (Ibrutinib/Acalabrutinib/Pirtobrutinib/Nemtabrutinib). The CD5+/CD19+ tumor population was enriched by flow sorting. We performed whole genome sequencing (WGS) in tumor/germline pairs with an average sequencing depth of 60X. Copy number variants (CNVpytor), structural variants – SV (Manta and DELLY2), single nucleotide variants (SNV) and indels (MuTect2, Strelka) were calculated. Mutational signature analysis was conducted independently on each disease timepoint with sigProfiler. De novo signatures were extracted with non-negative matrix factorization, then decomposed and mapped to known signatures from the COSMIC Human Cancer Signatures database. Results: Prior to start of BTKi treatment, the most common abnormality was del13q (65%), followed by abnormalities in TP53 (mutation and/or del17p) in 59% of patients, del8p, del11q (23% each), and mutations in SF3B1 (35%), NFKIE, NOTCH1 and MAPK signaling pathway (BRAF, KRAS, NRAS, PTPN11) in 23% of cases, each. Complex karyotype, defined as >3 copy number abnormalities was found in 59% of cases. Disease progression was observed 4.4 years (median; range 1.9-10.8 yrs) after starting BTKi therapy. At disease progression, there was an overall increase in genomic complexity. Overall, 17 cases (56%) showed mutations in BTK (p.C481S, p.C481Y, p.L528W, p.A428D) and/or PLCG2 (p.P844H). Four cases showed mutations in both genes or two or more independent mutations in BTK. Del17p and/or TP53 mutations were found in 20 (67%) cases, 9 of them with biallelic abnormalities. A third of patients (N=10) were found to have MAPK mutations, and 9 (30%) cases had mutations in the epigenetic regulators CREBBP, SETD2, SETD1A andKMT2D. Loss of heterozygosity, including 11q and 17p was found in 13% of cases. Chromothripsis was found in 23% of cases. In patients without BTK or PLCG2 mutations (N=13), TP53 abnormalities were present in 92% of cases and mutations in the MAPK pathway in 46% of these patients. Finally, we identified several SVs involving driver genes at disease progression, including inversions in RB1 (N=1), NOTCH1 (N=1) and translocations in MYC (N=1) and IGH (N=2). Analyzing the mutational signatures, baseline timepoints were dominated heavily by aging signatures (SBS5, SBS1). However, in cases that progressed after therapy, we found enrichment of mutational signatures associated with defective DNA mismatch repair (SBS44, 6%), chemotherapy treatment (SBS25, 14%), homologous and nucleotide excision repair deficiency (SBS8, 48%), and indirect effects of AID-induced somatic mutagenesis (SBS85, 7%). Additionally, the Melphalan signature (SBS99, 10%) was found in patients treated alkylating agents. Conclusions: Disease progression of CLL on BTKi confirmed the existence of multiple driver genes beyond BTK, PLCG2 andTP53, including the high prevalence of mutations in MAPK pathway and epigenetic regulators, and increased genomic complexity. Ongoing efforts are focused on integrating these findings with clinical demographics, epigenetic modifications, and preclinical drug sensitivity profiles.

Abstract Introduction Detecting genetic abnormalities is mandatory during diagnostic workup and for potential individualization of therapy selection in multiple myeloma (MM) and its precursor conditions. At present, this requires invasive bone marrow (BM) biopsies, severely limiting early detection, patient monitoring, and the precise selection of therapy. The current standard for detecting genetic alterations in MM is fluorescence in situ hybridization (FISH), which cannot detect point mutations and other clinically relevant alterations. Consequently, the IMS-IMWG guidelines were recently updated to require next-generation sequencing for the classification of high-risk MM. Moreover, the importance of identifying alterations in therapeutic targets (e.g., BCMA, GPRC5D) for guiding immunotherapies is becoming increasingly recognized. To address this need, we recently launched GenoPredicta, a CLIA-approved Laboratory Developed Test that enables routine monitoring, informing diagnosis, and treatment selection by comprehensively and robustly characterizing MM genomes with whole genome sequencing (WGS) from a minimum of ~50 circulating tumor cells (CTCs) isolated from peripheral blood (PB) or tumor cells from BM. Here, we describe the characterization of clinical and research samples with GenoPredicta, highlighting resistance-conferring genetic alterations that can only be detected by sequencing and that are consistent with patients' clinical histories, while further demonstrating the complete concordance of GenoPredicta with prior FISH results. Methods Tumor cells were isolated from BM and/or PB samples using fluorescence-activated cell sorting (FACS) (after CD138+ enrichment for PB) and subjected to whole genome sequencing (WGS), from which we identified copy number alterations, structural variants, and single nucleotide variants and indels. For a subset of samples, the BM was also characterized by FISH, using a standard clinical panel for characterizing MM; for other samples prior FISH results were available from patients' clinical records. Results The analytical validation of GenoPredicta, conducted on a retrospective cohort of >60 viably frozen samples from >30 patients, showed complete concordance between BM and PB for detected genomic abnormalities, with all clinically relevant events (11 translocations and 125 CNVs) observed in BM recapitulated in PB (100% recall). All events identified by FISH in 14 samples (8 translocations and 30 CNVs) were also identified in the BM (100% recall), with 50 translocations and 30 CNVs not detected by FISH also absent in the WGS data (100% precision). The abnormalities detected in these samples also included multiple high-risk events not assayed by FISH, including biallelic TP53 loss (Del 17p coupled with a deleterious TP53 mutation, observed in 4 patients) and MYC::IGL translocations (2 patients). Moreover, for all fresh peripheral blood clinical samples with FISH results available from patients' histories, GenoPredicta recalled 100% of reported events. Among these clinical samples, we notably observed a case with both a biallelic GPRC5D deletion and a TNFRSF17 (BCMA) deletion combined with a truncating mutation on the remaining allele. This was consistent with the patient's clinical history showing progression after therapy with talquetamab (anti-GPRC5D bispecific), and previous nonresponse to teclistamab (anti-BCMA bispecific) after prior therapy with Cilta-cel (BCMA-directed CAR T). GenoPredicta also detected other mutations likely to confer resistance to immunotherapies, including loss-of-function mutations in IKZF3 and deletions of FCRL5 in frozen peripheral blood research samples. Conclusion We demonstrate that WGS-based characterization of MM from BM or CTCs is a viable replacement for FISH for clinical diagnosis and monitoring, with blood-based measurements enabling comprehensive profiling of the myeloma cancer genome. Importantly, this includes genetic alterations that confer resistance to therapy, allowing for both early detection of such alterations and more precise selection of therapy.

Abstract Background: Partial tandem duplications of the histone methyltransferase KMT2Agene(KMT2A-PTD) are the most common KMT2A-aberration in adult acute myeloid leukemia (AML). KMT2A-PTD AML represents a high-risk disease subset with a poor prognosis. However, KMT2A-PTD leukemia is under studied, likely due to a lack of experimental models, and therefore the underlying mechanisms of leukemogenesis remain elusive. Since KMT2A-PTD leukemias possess high-level expression of HOXAgenes, similar to KMT2A-rearranged (KMT2A-r) and NPM1c AML, patients with this type of AML are currently enrolled into several phase I/II trials assessing menin inhibitors (MIs). However, mechanistic or clinical evidence for treatment response is lacking. To date, no targeted therapeutic approaches for KMT2A-PTD leukemia are available. Results: To better understand KMT2A-PTD mediated leukemogenesis, we endogenously tagged the KMT2A-PTD or KMT2A-wildtype (WT) allele in EOL-1 cells with a dTAG that can be degraded with PROTACs. Targeted protein degradation showed that the KMT2A-PTD, but not the KMT2A-WT protein, is critical to maintain leukemia cell growth. We identified KMT2A-PTD specific genome-wide chromatin binding sites and direct target genes as assessed by changes in nascent RNA production that started to occur within 30 minutes of KMT2A-PTD degradation. KMT2A-PTD target genes identified in this study included HOXA9, HMX2, HMX3, CDKN2C, MYC and CDK6 among others. Having defined the KMT2A-PTD target gene program, we assessed the effect of MI on KMT2A-PTD function. In KMT2A-PTD cell lines, PDXs and cells from a published murine KMT2A-PTD/FLT3-ITD knockin model, we observed intrinsic resistance to revumenib characterized by retained chromatin binding of KMT2A-PTD, but not KMT2A-WT after MI treatment. We next defined critical domains for KMT2A-PTD function via a KMT2A domain scan. This revealed the CXXC domain and AT hooks as critical dependencies in EOL-1 cells. Overexpression of KMT2A or mutants with duplicated domains in 293T cells showed that a duplication of the CXXC domain or the AT hooks is sufficient to mediate retained KMT2A chromatin binding under MI. Therefore, the resistance to MIs is likely due to the duplicated protein of KMT2A subverting menin function at critical target loci. Given that KMT2A-PTD remains chromatin-bound upon menin inhibition, we focused on ENL as a potential regulator of leukemia gene expression programs. In KMT2A-r and NPM1c leukemia, the ENL protein has been shown to be a critical dependency as it associates with acetyl lysine via its YEATS domain. ENL/AF9 YEATS inhibitors reverse ENL-dependent gene expression including HOXA9 and MYC. Using the small molecules TDI-11055 and TM-7, we show that YEATS inhibition leads to loss of members of the super-elongation complex and DOT1L from KMT2A-PTD driven loci and downregulation of target gene expression. Treatment of KMT2A-PTD PDXs with YEATS inhibitors induced differentiation and significantly reduced leukemia burden in vivo. Interestingly, we show that in contrast to previous findings in KMT2A-r leukemia, loss of ENL alone is insufficient to abrogate leukemic proliferation of EOL-1 cells. Instead, by combining ENL degradation with CRISPR-Cas9 mediated knockdown of AF9, we find that both YEATS proteins, ENL and its paralogue AF9, support aberrant gene expression in KMT2A-PTD leukemia. Finally, we show that the novel combination of MI and YEATS inhibition (revumenib plus TDI-11055) synergistically affects proliferation and induces differentiation in cell line and PDX models of KMT2A-PTD leukemia, which in turn prolongs survival of mice with KMT2A-PTD leukemia. Conclusions: KMT2A-PTD leukemia is dependent on the mutated, but not the WT KMT2A allele. It is characterized by a relative, intrinsic resistance to MI monotherapy, which is mediated by a duplication of the CXXC domain and AT hooks of KMT2A. Targeting both, the ENL and AF9 YEATS domain, is a possible treatment strategy and when combined with revumenib, YEATS inhibition has synergistic effects and overcomes intrinsic MI resistance. However, based on our studies, MI monotherapy may not be effective for most patients with KMT2A-PTD leukemia. Given that numerous compounds targeting the ENL (and AF9) YEATS domain are under study and MIs have recently obtained FDA approval, the combination of MI and YEATS inhibition could be translated into clinical trials for patients with KMT2A-PTD leukemia in the relatively near future.

Abstract Background: Talquetamab (Talq), a GPRC5D-targeting bispecific antibody, shows promising activity in relapsed/refractory multiple myeloma (RRMM). However, outcomes in patients (pts) with soft tissue plasmacytoma (STP) remain poorly characterized. Method: We retrospectively analyzed 463 RRMM pts treated with Talq at 15 U.S. centers by Dec 2024. Pts were grouped by presence of STP at Talq start: (1) extramedullary disease (EMD; lesions not contiguous with bone), (2) paraskeletal disease (PSK; bone-contiguous), (3) EMD + PSK, and (4) No-STP. Those receiving Talq as a bridge-to-CAR T (n=103, 22%) were censored at CAR T infusion if progression had not occurred. Time-to-event endpoints were calculated from Talq step-up, using Kaplan-Meier/Cox models. Result: Median age was 66 years (y) (35–89); 54 (11.7%) had EMD, 26 (5.6%) PSK, 60 (13%) EMD+PSK, and 320 (69%) No-STP. EMD pts were younger than No-STP (62 vs 66 y, p=.009), while PSK (66.5) and EMD+PSK (64.5) were similar to No-STP. Median prior lines were higher in PSK (7) vs EMD (5), EMD+PSK (6) and No-STP (6) (p=.035). Median time from diagnosis to Talq was shortest in EMD (3.8 y), followed by EMD+PSK (4.6 y), vs PSK (6.4 y), and No-STP (5.9 y) (p=.015). Among pts with any EMD (EMD or EMD+PSK), 81 (69%) had visceral involvement and 85 (73%) had multiple lesions. Rates of prior BCMA- or GPRC5D-directed therapy, plasma cell leukemia (≥5% circulating plasma cells at the time of Talq), and penta-refractoriness were similar across groups. ECOG ≥ 2 at Talq was more common in EMD (42%), PSK (39%), EMD+ PSK (37%) than in No-STP (23%) (p = .002). Other baseline features were similar. Cytokine release syndrome (CRS) rate/severity were similar across groups. The immune effector cell–associated neurotoxicity syndrome (ICANS) was more frequent in PSK (38%) vs EMD (11%), EMD + PSK (18%), and No-STP (11%), with the most PSK cases (60%, 6/10) being grade ≥2 (p=.006). No difference in CRS/ICANS onset or duration. Infection rates were lower in No-STP (36%) vs EMD (55%), PSK (46%), and EMD+ PSK (48%) (p=.025). Best overall response rates (ORR) were 71% in EMD, 68% in PSK, 67% in EMD+PSK, and 71% in No-STP (p=.9). Complete response (CR) rates were 14% in EMD, 20% in PSK, 13% in EMD+ PSK, and 25% in No-STP (p=.1) [CRs were not required to be confirmatory, which may not meet full IMWG criteria]. Radiographic response was evaluable in 41 EMD (86%), 16 PSK (61.5%), and 48 EMD+PSK (80%) pts, with partial response (PR) or better observed in 48%, 27%, and 38%, respectively. Among pts with any STP, 34% received radiation (XRT) (4 as bridge-to-CAR T), 24 (51%) were evaluable, and 71% (n=17) achieved ≥PR. The median follow-up from Talq initiation was 10.1 months (mo) (95% CI: 8.8–11.4) and was longest in EMD (13.9 mo) compared with PSK (10.8 mo), EMD+PSK (12.4 mo), and No-STP (9.8 mo) (p = .040). Median progression-free survival (PFS) was 4.3 mo (95% CI: 3.6–5.06) in EMD, 4.8 mo (95% CI: 2.2–7.3) in PSK, 3.8 mo (95% CI: 3.1-4.5) in EMD+ PSK, and 8.3 mo (95% CI: 7.0–9.6) in No-STP (p <.001). Among pts receiving XRT for any STP (within 4 weeks prior to or during Talq), responders had longer PFS vs non-responders (15.4 vs. 2.4 mo; p=.009). Multivariable analysis (MVA) showed inferior PFS with EMD (Hazard Ratio (HR) 1.58; 95% CI, 1.04-2.3; p=.029), EMD+PSK (HR 1.91; 95% CI, 1.2–2.8; p = .001), ECOG ≥ 2 (HR 1.4; 95% CI, 1.04–1.9; p = .024), and del(17p) at any timepoint (HR 1.99; 95% CI, 1.1–3.5; p=.017), while longer time from diagnosis to Talq was modestly protective (HR 0.95 per year; p = .016), likely reflecting less aggressive biology in those reaching 5th+ line later. PSK alone showed a non-significant trend toward inferior PFS (HR 1.5; p = .1). Median overall survival (OS) was 13.0 mo (95% CI: not reached [NR]–NR) in EMD, 12.9 mo (95% CI: 6.9–18.9) in PSK, 10.9 mo (95% CI: NR–NR) in EMD+PSK, and NR (95% CI: NR–NR) in No-STP (p = .017). The primary cause of death was disease-related across all groups (p = .6). MVA for OS showed worse outcomes with EMD+PSK (HR 1.7; p=.033), ECOG ≥ 2 (HR 1.98; p <.001), and active PCL at Talq (HR 2.1; p =.010). Conclusion: Soft tissue plasmacytoma, particularly EMD and EMD+PSK, remain strong adverse prognostic factors in Talq-treated patients, with significantly shorter PFS and OS despite similar response rates. Radiation to STP sites was associated with improved outcomes in select cases. Prospective strategies are needed to optimize management for this high-risk population.

Abstract Background Talquetamab (talq) is a GPRC5D-directed bispecific antibody (BsAb) approved for the treatment of relapsed and refractory multiple myeloma (RRMM). The pivotal monumenTAL-1 clinical trial did not include patients with renal impairment (RI, creatinine clearance<40 mL/min) and therefore, data for the use of this agent in RI is lacking. Methods We examined the outcomes of patients with RRMM treated with standard of care (SOC) talq in a multicenter, retrospective cohort study. RI was defined as creatinine clearance (CrCl) <40 mL/min. For each patient we recorded demographics, disease characteristics, prior therapies, incidence and severity of adverse events of special interest, namely cytokine release syndrome (CRS) and immune-cell associated neurotoxicity syndrome (ICANS), along with response, progression-free (PFS) and overall survival (OS). We compared binary variables between different groups using Chi-squared test and assessed progression free survival (PFS) and overall survival (OS) using Kaplan Meier and Cox proportional hazards models. Patients who received talq as a bridge therapy prior to chimeric antigen receptor T-cells (CART cells) were censored for PFS analysis at the time of subsequent therapy. Results We included 417 patients who received SOC Talq and had complete datasets. 91 (22%) had RI, including 20 (5%) on dialysis. The median age was 68 and 65 years for patients with and without RI. Patients with RI were more likely to be female (64% vs. 51%), less likely to have prior CART cells (35% vs. 48%). There were no differences in performance status, race, presence of high-risk cytogenetic abnormalities [del17p, t(4;14), t(14;16), gain/amplification 1q], lines of prior therapy (median 6 vs. 6), prior ASCT (68% vs. 72%), presence of CNS disease (4% vs. 4%), prior plasma cell leukemia (8% vs 9%), prior BCMA therapy (54% vs. 61%) and triple class refractory disease (90% vs. 94%) among patients with and without RI. Rates of CRS (63% vs. 56%, P=0.21) were similar in the two groups, while severe CRS (grade ≥3: 6% vs 2%, P=0.02) was more common in patients with RI. Any grade (20% vs 14%, P=0.21) and high grade ICANS (grade ≥3: 4% vs 4%, P=0.97) were similar in patients with and without RI. There was no difference between groups on risk of infection (P=0.65) with cumulative risk at 6 months of 39% vs. 40%. With 11.1 months of median follow up, the overall response rate (60% vs 67%; P = 0.12), and progression-free survival (median 7.3 vs. 6.5 mo.; P = 0.9) were comparable between the two groups. There was no difference in outcomes according to RI in both patients previously treated with BCMA-directed therapy and BCMA-naïve. Conversely, among patients with RI, median PFS was 4.6 and 8.5 mo. for patients with and without prior BCMA therapy. Similarly, among patients without RI, median PFS was 6.5 and 6.2 mo, respectively. Among BCMA-naïve patients, there was no difference in OS between patients with and without RI (median not reached, 12 mo. OS rate 71% vs. 73%, P=0.53), while among patients with prior BCMA-directed therapy there was a trend towards better OS for patients without RI (median 8.9 vs. 13.8 mo; 12 mo. OS rate 43% vs 59%, P=0.06). Five patients (25%) became dialysis independent following talq therapy. On multivariable analysis, ECOG >1 (HR 1.62, 95% C.I. 1.25-2.10, P<0.001) and deletion of 17p (HR 1.55, 95% C.I. 1.17-2.06, P=0.003) but not RI or prior BCMA-directed therapy affected PFS. OS was affected by ECOG >1 (HR 2.37, 95% C.I 1.71-3.30, P<0.001), triple-class refractoriness (HR 3.03, 95% C.I. 1.12-8.21, P=0.03) and prior BCMA-directed therapy (HR 1.79, 95% C.I. 1.24-2.59, P=0.002) but not by RI. Conclusion Our findings support the feasibility of talq in patients with RI, including those on dialysis, with similar safety and efficacy profile to patients without RI. While neither prior BCMA-directed therapy nor RI affect PFS, refractoriness to conventional agents and prior exposure to BCMA-directed therapy adversely affects OS. This observation likely reflects better post progression survival following talq due to the availability of efficacious therapeutic options, including those directed at BCMA.

Abstract Background Translocation of chromosomes 4 and 14 (t(4;14)) results in overexpression of MMSET and has been associated with poor clinical outcomes in patients (pts) with multiple myeloma (MM). KTX-1001 is a first-in-class, potent, and selective oral inhibitor of MMSET (also known as NSD2) developed as the first investigational therapy to directly target the high-risk t(4;14) translocation, a key molecular driver in MM. KTX-1001 binds to and inhibits the catalytic SET domain of MMSET, thereby suppressing the deposition of dimethylated histone H3 lysine 36 (H3K36me2), leading to downregulation of oncogenic histone modifications and epigenetic reprogramming of malignant plasma cells. Preclinically, KTX-1001 synergistically inhibited cell viability in MM cell lines when combined with a proteasome inhibitor (PI), immunomodulatory drug (IMiD), or cereblon E3 ligase modulator (CELMoD™). Preliminary findings were previously reported from the initial cohort of 18 pts enrolled in a first-in-human phase 1 trial evaluating KTX-1001 in relapsed/refractory multiple myeloma (RRMM; NCT05651932; Bories et al. Blood. 2024;144[Suppl 1]:3370). Here, we present updated results from this study. Methods RRMM pts who received ≥3 prior therapies, including PI, IMiD and anti-CD38 monoclonal antibody (anti-CD38 mAb), received oral KTX-1001 across 9 dose levels using a 3+3 dose-escalation design. Primary objective was to determine the recommended Phase 2 dose (RP2D) and the maximum tolerated dose (MTD). Secondary objectives included pharmacokinetics, pharmacodynamics (PD), and primary efficacy. The dose expansion phase has been initiated to evaluate KTX-1001 in combination with either carfilzomib or the investigational CELMoD™ mezigdomide in t(4;14) RRMM pts. Results As of 13 June 2025, 40 pts have been treated in the monotherapy dose-escalation phase. The maximum tolerated dose (MTD) was exceeded due to dose-limiting toxicities (DLTs) in 2 pts: two Grade (Gr) 4 thrombocytopenia and one Gr 3 epistaxis. Backfill at selected dose levels is ongoing to further characterize safety profile and refine dose optimization. The median time from initial MM diagnosis was 8 years (range:2-20) with a median of 6.5 prior lines of therapy (range: 3-25). This included stem cell transplant (70%), BCMA CAR-T (42.5%), and non-CAR-T BCMA targeted drugs such as antibody-drug conjugates and bispecific antibodies (57.5%). The median age was69 years (range:50-83); 21 were female and 19 were male. Extra-medullary disease was present in 13 (32.5%) pts. Nineteen (47.5%) pts had t(4;14) translocation, 5 (12.5%) had 1q21 gain and 4 (10%) had deletion 17p. A total of 16 (40%) pts have shown a treatment response according to IMWG criteria or have achieved stable disease: 1 VGPR (10+ months), 1 PR (4+ months), 2 MR (3+ and 12 months), 12 SD (2-20+ months). KTX-1001 has demonstrated a favorable tolerability profile. Grade 3 or higher treatment-emergent adverse events (TEAEs) were reported in 31 (77.5%) pts. The most frequent (≥20% pts) Gr 3/4 TEAEs were thrombocytopenia in 12 pts (30%; grade 4 in 8 [20%]), neutropenia in 12 pts (30%; febrile neutropenia in 2 [5%]), anemia in 10 (25%) pts. Gr 3 infections were observed in 5 (12.5%) pts and fatigue in 5 (10%) pts. The main reason for treatment discontinuation was progressive disease (57.5%), other pts discontinued due to physician decision (5%), consent withdrawal (5%), and one pt due to adverse event. Twelve (30%) pts remain on treatment. At Cycle 1 Day 15, drug exposure and steady-state concentrations of KTX-1001 increased with dose. A dose-dependent reduction in H3K36me2, the primary PD marker of KTX-1001 activity, was observed in peripheral blood at Cycle 2 Day 1 and beyond, which plateaued above dose-level 4. Paired bone marrow samples further confirmed on-target PD effects, with a marked reduction in H3K36me2 levels in MM cells at Cycle 2 Day 1 with observed anti-MM effect of reduced proliferation of MM cells with concomitant increased proliferation in immune cells in pts achieving clinical benefit. ConclusionsKTX-1001 is a novel agent showing tolerable safety profile in RRMM and demonstrating promising single agent activity in heavily pretreated, triple class refractory RRMM including those with high-risk features. KTX is currently evaluated in ongoing study in combination with carfilzomib and the investigational CELMoD™ mezigdomide in t(4;14) RRMM pts.

Abstract INTRODUCTION Outcomes for 1st relapse of pediatric B-lymphoblastic leukemia (B-ALL), especially high/intermediate-risk (HR/IR) relapse, remain unacceptably poor. Limited enrollment of this population on cooperative group clinical trials has impeded our ability to study potentially effective regimens. In the current era, patients can access innovative immunotherapies commercially. However, there is no mechanism to capture outcomes for these off-study patients and no comparative effectiveness data to guide treatment selection. METHODS We conducted a multicenter, retrospective study of patients <30 years who initiated 1st relapse therapy at a participating center from 2018-2022 (ReCALL-1 Study). Objectives were to define real-world survival outcomes, compare response rates of reinduction strategies, describe the post-reinduction treatment landscape, and, for patients with HR/IR relapse, assess the comparative effectiveness (CE) of blinatumomab to hematopoietic cell transplant (blina/HCT) v CD19 CAR T cells (CART). For the CE analysis, we emulated an open-label, randomized study of blina/HCT v CART who achieved an M1/M2 marrow at the end of an intensive reinduction (EoRI). Patients were classified by their intended treatment at EoRI. Cox regression models were used to adjust for unbalanced patient and disease features by arms. The primary outcome was overall survival (OS) from EoRI. RESULTS The full cohort included 479 patients from 33 centers (31 US, 2 international). Median time to relapse was 31 months (m); 77% had bone marrow (BM) involvement and 31% central nervous sytem involvement. With a median follow-up of 49m from relapse, 4 year (y) OS, event-free survival (EFS), and non-relapse mortality (NRM) were 64%, 43%, and 13%, respectively. Among patients with very early BM (<18m, n=79), early BM (18-35m, n=76), late BM (≥36m, n=162), and isolated CNS (n=85) relapses, 4y OS/EFS were 29%/20%, 57%/35%, 78%/49%, and 84%/61%, respectively. Only 19% received reinduction therapy on a clinical trial. Among patients with BM disease, R3 reinduction (n=179) and VXLD (n=61) had identical MRD-negative (<0.01%) CR rates of 38% (p=1.00) and equivalent treatment failure (TF; M3 or extramedullary disease) rates: R3, 8% v VXLD 7%, p=0.79. Blina (n=33) and inotuzumab-based (n=21) reinductions achieved MRD-negative CR rates of 39% and 52%, respectively, but higher TF rates of 39% and 24%. Reinduction mortality was 2%: R3, n=5; VXLD, n=3; 3-drug reinduction, n=1. Overall, as part of 1st relapse therapy, 36% received CART (78% commercial product), 44% HCT, 40% blina, and 11% inotuzumab. The emulated trial included 159 patients, 95 on blina/HCT and 64 on CART. Study arms were well matched by demographics, cytogenetics, and relapse sites, but CART patients were more likely to have relapsed <18m from diagnosis (34% v 24%) and have EoRI M2 marrows (31% v 11%), and less likely to have private insurance (36% v 51%). Unadjusted OS was comparable between arms (log rank p=0.18): CART, 60% at 4y; blina/HCT, 71%, as was NRM (10% v 13% at 4y). EFS was lower for CART (p=0.049): 4y EFS 35% v 49% for blina/HCT. After adjustment for unbalanced covariates, the hazard of death was equivalent for CART as compared to blina/HCT (aHR 1.1, 95% CI 0.6-2.1, p=0.67) and EFS became more comparable (aHR 1.3, 95% CI 0.8-2.1, p=0.22). 91% of blina/HCT and 97% of CART received their intended cell therapy; time from EoRI to cell therapy was shorter for CART (67 v 86 days, p<.001). In the CART arm, 34% underwent consolidative HCT; 1/3 were preplanned and 2/3 due to loss of B cell aplasia or NGS-MRD positivity. Of those with a 2nd relapse, CART patients were more likely to be CD19 negative (47% v 10%, p=0.003). CONCLUSION In this multicenter, real-world cohort of children treated for 1st relapse in the immunotherapy era, suboptimal outcomes for early BM relapse persisted, with particularly dismal 4y OS of 29% for relapses <18m after diagnosis. In contrast, survival for late BM and isolated CNS relapses compared favorably to historic data. Only 1 in 5 patients initiated relapse therapy on a clinical trial and although 1st relapse is not an approved indication for commercial CART in pediatrics, 36% received CART. In an emulated trial of post-reinduction blina/HCT v CART, adjusted EFS and OS were comparable, suggesting that CART may be a viable alternative to HCT for select patients. Post hoc analyses will identify whether specific subgroups may benefit more from one strategy.

Objectives Damaged articular cartilage cannot regenerate spontaneously. Chondrocyte therapy, the current treatment of choice, requires laboratory expansion, necessitating two surgical procedures. Adding a second cell type to intraoperatively isolated chondrocytes enables single-stage chondrocyte-based repair strategies and has shown promise in vitro . The benefit of this strategy in vivo and in the clinic has not yet been comprehensively assessed. This systematic review assesses the efficacy of cartilage repair by co-implantations of chondrocytes with other cell types over all available in vivo studies. Design Medline, Embase and Cochrane databases were searched for studies on co-implantations of chondrocytes with other cell types for hyaline cartilage repair. For each study, extracted data were tabulated and reporting quality and risk of bias were assessed. Studies were categorized based on their control groups for qualitative synthesis. Results The search yielded 48 studies across 46 publications: 44 animal studies (26 ectopic and 18 orthotopic) and four clinical trials. Ectopic studies scored poorly on reporting quality and bias, while orthotopic studies were only moderately better. Twenty-seven of 27 experiments with chondrocyte-only controls demonstrated synergistic cartilage formation through co-implantation. Cartilage formation by co-implantations was also found in 15 of 17 experiments without such control and in four clinical trials. Conclusion Cartilage repair by articular chondrocytes is improved by adding a second cell type, like mesenchymal stromal cells. This is likely caused by the second cell types’ stimulatory support. Other second cell types and chondrocyte sources have shown promising results too. This is encouraging for further clinical exploration of single-stage co-implantation strategies.

Abstract Consumption of a Western diet and high body mass index (BMI) are risk factors for progression from premalignant phenotypes to multiple myeloma, a hematologic cancer. In the NUTRIVENTION trial (NCT04920084), we administered a high-fiber, plant-based diet (HFPBD; meals for 12 weeks, coaching for 24 weeks) to 23 participants with myeloma precursor states and elevated BMI. The intervention was feasible and improved quality of life and modifiable risk factors: metabolic (BMI, insulin resistance), microbiome (diversity, composition), and immune (inflammation, monocyte subsets). Disease progression trajectory improved (n = 2) or was stable. Findings were translated to Vk*MYC mice modeling the myeloma precursor state, in which a high-fiber diet (HFD) delayed disease progression through improved metabolism and microbiome composition, leading to increased short-chain fatty acid production that reinvigorated antitumor immunity and inhibited tumor growth. These effects from fiber consumption were independent of calorie restriction and weight loss. A HFD is a low-risk intervention that may delay progression to myeloma. Significance: A HFPBD in participants with precursor plasma cell disorders and an elevated BMI improved metabolic, microbiome, and immune biomarkers of disease. In a subset, it may delay progression to myeloma. In mouse models, a HFD delayed progression to myeloma independent of calorie restriction. See related commentary by Fairfield and Reagan, p. 623