Sheri Skerget

In mammals, transit through the epididymis, which involves the acquisition, loss and modification of proteins, is required to confer motility and fertilization competency to sperm. The overall dynamics of maturation is poorly understood, and a systems level understanding of the complex maturation process will provide valuable new information about changes occurring during epididymal transport. We report the proteomes of sperm collected from the caput, corpus and cauda segments of the mouse epididymis, identifying 1536, 1720 and 1234 proteins respectively. This study identified 765 proteins that are present in sperm obtained from all three segments. We identified 1766 proteins that are potentially added (732) or removed (1034) from sperm during epididymal transit. Phenotypic analyses of the caput, corpus and cauda sperm proteomes identified 60 proteins that have known sperm phenotypes when mutated, or absent from sperm. Our analysis indicates that as much as one-third of proteins with known sperm phenotypes are added to sperm during epididymal transit. GO analyses revealed that cauda sperm are enriched for specific functions including sperm-egg recognition and motility, consistent with the observation that sperm acquire motility and fertilization competency during transit through the epididymis. In addition, GO analyses revealed that the immunity protein profile of sperm changes during sperm maturation. Finally, we identified components of the 26S proteasome, the immunoproteasome, and a proteasome activator in mature sperm.

ABSTRACT: Teclistamab and other B-cell maturation antigen (BCMA)-targeting bispecific antibodies (BsAbs) have substantial activity in patients with heavily pretreated multiple myeloma (MM) but are associated with a high rate of infections. BCMA is also expressed on normal plasma cells and mature B cells, which are essential for the generation of a humoral immune response. The aim of this study was to improve the understanding of the impact of BCMA-targeting BsAbs on humoral immunity. The impact of teclistamab on polyclonal immunoglobulins and B cell counts was evaluated in patients with MM who received once-weekly teclistamab 1.5 mg/kg subcutaneously. Vaccination responses were assessed in a subset of patients. Teclistamabinduced rapid depletion of peripheral blood B cells in patients with MM and eliminated normal plasma cells in ex vivo assays. In addition, teclistamab reduced the levels of polyclonal immunoglobulins (immunoglobulin G [IgG], IgA, IgE, and IgM), without recovery over time while receiving teclistamab therapy. Furthermore, response to vaccines against Streptococcus pneumoniae, Haemophilus influenzae type B, and severe acute respiratory syndrome coronavirus 2 was severely impaired in patients treated with teclistamab compared with vaccination responses observed in patients with newly diagnosed MM or relapsed/refractory MM. Intravenous immunoglobulin (IVIG) use was associated with a significantly lower risk of serious infections among patients treated with teclistamab (cumulative incidence of infections at 6 months: 5.3% with IVIG vs 54.8% with observation only [P < .001]). In conclusion, our data show severe defects in humoral immunity induced by teclistamab, the impact of which can be mitigated by the use of immunoglobulin supplementation. This trial was registered at www.ClinicalTrials.gov as #NCT04557098.

BACKGROUND: Talquetamab is the first GPRC5D × CD3 bispecific antibody approved for relapsed or refractory multiple myeloma. In phase 1 of the MonumenTAL-1 study, initial results of subcutaneous talquetamab 0·4 mg/kg once a week and 0·8 mg/kg every 2 weeks showed preliminary clinical activity. We describe safety and activity results in patients treated with talquetamab, including patients who had received previous T-cell redirection therapy (TCR). This post-hoc analysis was done with more mature median follow-up to evaluate duration of response in patients treated with talquetamab 0·8 mg/kg every 2 weeks. METHODS: MonumenTAL-1 is a multicentre, open-label, phase 1-2 study of talquetamab, phase 1 of which has previously been published. The 0·4 mg/kg once a week and 0·8 mg/kg every 2 weeks recommended subcutaneous doses identified in phase 1 were evaluated in phase 2 in patients who were 18 years of age or older, had at least three previous lines of therapy, had an Eastern Cooperative Oncology Group performance status of 0 to 2, and were naive or exposed to previous TCR. The primary endpoint was overall response rate assessed by independent review committee in all patients who received at least one dose of talquetamab. Safety was assessed in all patients who received at least one dose of talquetamab. This study was registered with ClinicalTrials.gov, NCT03399799 (phase 1) and NCT04634552 (phase 2). FINDINGS: Between Jan 3, 2018, and Feb 20, 2023, 735 patients were screened across all phase 1-2 cohorts. Of these, 537 patients screened for inclusion were treated across phase 1 and 2 cohorts, of whom 198 (27%) patients were excluded from the study, most commonly due to not meeting eligibility criteria or not having measurable disease. As of Oct 11, 2023, 375 patients had received recommended talquetamab doses across three groups: 143 (0·4 mg/kg once a week group) and 154 (0·8 mg/kg every 2 weeks group) TCR-naive patients and 78 with previous TCR who received either recommended dose (previous TCR group). 217 (58%) of 375 patients were male and 158 (42%) were female. 325 (87%) of 375 patients were White and 32 (9%) patients were Black. Median follow-up was 25·6 months (IQR 8·5-25·9) in the 0·4 mg/kg once a week group, 19·4 months (9·2-20·7) in the 0·8 mg/kg every 2 weeks group, and 16·8 months (7·6-18·7) in the previous TCR group. Overall response rate was 74% (106 of 143 patients, 95% CI 66-81) in the 0·4 mg/kg once a week group, 69% (107 of 154 patients, 62-77) in the 0·8 mg/kg every 2 weeks group, and 67% (52 of 78 patients, 55-77) in the previous TCR group. Most common adverse events in the 0·4 mg/kg once a week, 0·8 mg/kg every 2 weeks, and previous TCR groups were cytokine release syndrome (113 [79%] of 143 patients, 115 [75%] of 154 patients, and 57 [73%] of 78 patients), taste changes (103 [72%], 110 [71%], and 59 [76%]), and infections (85 [59%], 105 [68%], and 59 [76%]). Most common grade 3-4 adverse events were neutropenia (44 [31%], 33 [21%], and 37 [47%]), anaemia (45 [31%], 40 [26%], and 21 [27%]), and lymphopenia (37 [26%], 40 [26%], and 13 [17%]). Fatal adverse events occurred in five patients in the 0·4 mg/kg once a week group, seven patients in the 0·8 mg/kg every 2 weeks group, and no patients in the previous TCR group; none were related to treatment. INTERPRETATION: Talquetamab continued to demonstrate high overall response rates in heavily pretreated patients with relapsed or refractory multiple myeloma with longer follow-up in this post-hoc analysis. Overall response rate was promising in patients with previous TCR, including therapies targeting BCMA. On-target, off-tumour adverse events were common but led to few treatment discontinuations. FUNDING: Janssen.

Multiple myeloma is a treatable, but currently incurable, hematological malignancy of plasma cells characterized by diverse and complex tumor genetics for which precision medicine approaches to treatment are lacking. The Multiple Myeloma Research Foundation’s Relating Clinical Outcomes in Multiple Myeloma to Personal Assessment of Genetic Profile study ( NCT01454297 ) is a longitudinal, observational clinical study of newly diagnosed patients with multiple myeloma (n = 1,143) where tumor samples are characterized using whole-genome sequencing, whole-exome sequencing and RNA sequencing at diagnosis and progression, and clinical data are collected every 3 months. Analyses of the baseline cohort identified genes that are the target of recurrent gain-of-function and loss-of-function events. Consensus clustering identified 8 and 12 unique copy number and expression subtypes of myeloma, respectively, identifying high-risk genetic subtypes and elucidating many of the molecular underpinnings of these unique biological groups. Analysis of serial samples showed that 25.5% of patients transition to a high-risk expression subtype at progression. We observed robust expression of immunotherapy targets in this subtype, suggesting a potential therapeutic option. Longitudinal genomic and transcriptomic profiling of 1,143 patients with multiple myeloma by the Relating Clinical Outcomes in Multiple Myeloma to Personal Assessment of Genetic Profile study yields an improved copy number and gene expression subtype scheme, most notably a high-risk proliferative subtype associated with complete loss of RB1 or MAX.

ABSTRACT: Adoptive T-cell therapy is a promising therapy for multiple myeloma (MM), but its efficacy hinges on understanding the relevant biologic and predictive markers of response. B-cell maturation antigen (BCMA) is a key target antigen in MM with active development of multiple anti-BCMA T-cell engagers (TCEs) and chimeric antigen receptor T-cell therapies. The regulation of surface BCMA expression by MM cells, which leads to shedding of soluble BCMA (sBCMA), has triggered debate about the significance of sBCMA as a predictive marker and its potential impact on treatment outcomes. To address this, we leveraged whole-genome sequencing and in vitro assays to demonstrate that sBCMA may independently predict primary refractoriness to anti-BCMA therapies. In addition to sBCMA, tumor burden and surface BCMA antigen density collectively influenced the anti-BCMA TCE cytotoxic efficacy. Correlative analyses of 163 patients treated with the anti-BCMA TCE teclistamab validated and further underscored the association between elevated baseline sBCMA (>400 ng/mL) and refractoriness. Importantly, increasing the TCE dose, using TCE against alternative targets (eg, GPRC5D), and gamma secretase inhibitors were able to overcome the high sBCMA levels. These findings highlight the importance of taking into account the baseline sBCMA levels, disease burden, and TCE dose intensity when administering anti-BCMA TCEs, thereby offering critical insights for optimizing therapeutic strategies to overcome specific high-risk features and primary anti-BCMA TCE refractoriness.