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61 citation(s) found for "Quach, H".

Innovations in Microsurgery: A Qualitative Appraisal of a Novel 3D-Printed Microscope
Zona, Emily E. , Eftekari, Sahand, Wu, Elizabeth P., Quach, Myiah Phuong Kim, Shaffrey, Ellen C , Carbullido, M Kristine, Zeng, Weifeng , Dingle, Aaron M

Journal of Reconstructive Microsurgery | October 7, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.1055/a-2972-6217 | PMID 42838114 Get It

Background Microsurgery is a critical component of plastic and reconstructive surgery. However, the high cost of training and equipment pose significant barriers, particularly in resource-limited settings. To address this challenge, the Microsurgery and Regenerative Medicine Lab within the Division of Plastic Surgery at the University of Wisconsin developed a low-cost, 3D-printed surgical microscope. This study qualitatively appraised the use of this novel microscope for microsurgery training by surveying surgeons about their experiences using this tool relative to traditional magnification methods. Methods In this prospective, multi-institutional appraisal study, surgical residents, fellows, and attending surgeons with varying microsurgical experience performed a single end-to-end microsurgical anastomosis on chicken thigh femoral arteries using the 3D-printed microscope. Participants then completed a survey assessing ease of use, adequacy for microsurgical training, educational value, and perceived impact on teaching capacity in local and global settings. Results Over 80% of participants reported that performing an end-to-end anastomosis was easier or equivalent using the 3D-printed microscope compared to surgical loupes. All respondents expressed willingness to use the device for microsurgery teaching and practice. Additionally, 91.7% (33/36) believed access to the microscope would enhance microsurgical teaching at their home institutions, and 97.1% (34/35) felt it would improve teaching capacity in globally. Qualitative feedback was overwhelmingly positive, with suggestions primarily related to ergonomics and lighting. Conclusion This study supports that this low-cost, 3D-printed microscope is an effective microsurgical training tool. Ongoing design refinements informed by user feedback may further optimize its role in expanding access to microsurgery education worldwide.
Supernatants from stored platelet concentrates modulate the inflammatory response in platelet-depleted blood ex vivo
Andersson, Linnéa , Sjöström, Dick J. , Tynngård, Nahreen , Mohlin, Camilla , Quach, Huy Quang , Tjernberg, Ivar , Ramström, Sofia , Mollnes, Tom Eirik , Nilsson, Per H.

Frontiers in Immunology | October 5, 2026 | Volume: 17 | Issue: No issue available | Pages: No page available

10.3389/fimmu.2026.1928875 Get It

Introduction Platelets contain a wide range of bioactive mediators, many of which accumulate during storage of platelet concentrates and have immunomodulatory properties. Our objective was to investigate how mediators derived from stored platelet concentrates modulate the acute inflammatory response using an ex vivo model. Methods Platelet-depleted whole blood from healthy donors (n=8) was supplemented with pooled platelet concentrate supernatants generated from six platelet concentrates sampled on storage days 1, 3, 5, and 7, and incubated with or without heat-inactivated Escherichia coli for four hours at 37 °C. Inflammatory responses were assessed by measuring complement activation, platelet-derived mediators, and cytokines. Results In the absence of E. coli , addition of platelet concentrate supernatants increased the levels of 24 of 32 measured inflammatory mediators. In contrast, under E. coli -stimulated conditions, the supernatants increased 10 markers and attenuated 14 markers, including the key pro-inflammatory cytokines IL-1β, IL-6, and TNF. The attenuation of these cytokines ranged from 25-43%, whereas several other mediators were unchanged or increased. The majority of biomarkers showed limited differences across the investigated storage time points. Conclusions Our findings demonstrate that soluble factors released from platelet concentrates can modulate inflammatory responses in platelet-depleted blood in an ex vivo setting, with context-dependent, bidirectional, and selective immunomodulatory effects.
Safety and reliability of isatuximab subcutaneous on-body injector: Results across the phase 3 IRAKLIA, phase 2 IZALCO and phase 1b TCD15484 trials.
Leleu, Xavier P., Cerchione, Claudio, Ailawadhi, Sikander, Minarik, Jiri, Špička, Ivan, Rocafiguera, Albert Oriol, Ocio, Enrique M., LeBlanc, Richard, Parmar, Gurdeep , Yañez, Eduardo, Cao, Carmen, Rojas, Christine , Xia, Zhong-Jun, Wang, Y L , Khan, Umer, Stefanova-Urena, Maya, Suzan, Florence, Moreau, Philippe, Quach, H, Leleu, Xavier , Cerchione, Claudio , Ailawadhi, Sikander , Minařík, Jiří , Špička, Ivan, Ocio, Enrique M. , LeBlanc, Richard , Xia, Zhong-Jun, Moreau, Philippe , Quach, Hang

Journal of Clinical Oncology | May 28, 2026 | Volume: 44 | Issue: 16_suppl | Pages: 7563-7563

10.1200/jco.2026.44.16_suppl.7563 Get It

7563 Background: Subcutaneous (SC) drug delivery options have become more widely available in multiple myeloma (MM). SC delivery of isatuximab (Isa), an anti-CD38 monoclonal antibody, has been investigated across clinical trials via a novel hands-free on-body injector (OBI). Isa SC OBI features a small, retractable needle, establishing the first device-enabled delivery of an oncologic treatment. The Phase 3 IRAKLIA, Phase 2 IZALCO, and Phase 1b (TCD15484) trials consistently demonstrated similar efficacy and safety of Isa SC OBI vs Isa IV in relapsed/refractory MM (RRMM) patients (pts). Here, we present a cross-trial analysis exploring safety and reliability of Isa SC OBI in RRMM pts. Methods: Pts with RRMM in IRAKLIA (N=263) and the Phase 1b expansion cohort (N=22) received 1400 mg Isa SC OBI plus pomalidomide and dexamethasone (d). In IZALCO, RRMM pts (N=64) received 1400 mg Isa SC OBI + carfilzomib (K)-d. Pts were monitored for 4 hrs (IRAKLIA) or 1-2 hrs (IZALCO) following first administration and for 1 hr for the following cycle (C) 1 administrations to assess local tolerability. Pre-infusion medications included montelukast (C1), steroids, acetaminophen and H1 antihistamines. Pts without systemic infusion-related reactions (IRRs) after 4 consecutive administrations of Isa SC OBI had subsequent pre-medication reassessed at investigator’s discretion. Safety and device performance explored in this cross-trial analysis of company sponsored studies were assessed in the Isa SC OBI cohorts by the duration of injection, IRRs, local injection-site reactions (ISRs), and injection/device success, which were defined similarly across all trials. Results: The median duration of Isa SC OBI injection was 13 mins in IRAKLIA, 12 mins in IZALCO, and 10 mins in the Phase 1b trial (6426 total injections, N=349 pts). IRRs across trials occurred in 6/6426 (0.09%) injections and 4/349 (1.15%) pts. IRRs were mostly grade 1 (G; 3/6426, 0.05%) with 1 G3 (0.02%); none leading to discontinuation. In IRAKLIA, 80/263 (30.4%) pts did not require premedication (931/5145 injections, 18.1%); no IRRs occurred in this group. Across trials, ISRs occurred in 21/349 (6.02%) pts resulting in 35 (0.54%) ISR events. Most ISRs were G1 (33, 0.51%), the remaining were G2 (2, 0.03%) and generally occurred on the day of injection. 99.9% (6421/6426) of injections in 98.6% (344/349) pts were successful (completed without interruption) across all trials. Conclusions: These findings support overall low, self-limiting rates of IRRs and ISRs across trials, with >6000 (99.9%) Isa SC OBI injections successfully delivered. Isa SC OBI shows reproducible safety and reliability in IRAKLIA, IZALCO and Phase 1b trials, supporting it as a novel administration option for MM pts and its potential for future exploration in at-home administration. Clinical trial information: NCT04045795 , NCT05405166 , and NCT05704049 .
Infections in patients receiving daratumumab for newly diagnosed multiple myeloma: a pooled analysis of MAIA and ALCYONE
Bahlis, Nizar J. , Facon, Thierry, San-Miguel, Jesus, Usmani, Saad Z., Dimopoulos, Meletios-Athanasios A., Moreau, Philippe, Manier, Salomon , NS, Raje, Orlowski, Robert Z. , Goldschmidt, H, Hulin, Cyrille, Weisel, K, Leleu, Xavier, Plesner, Torben , Jakubowiak, Andrzej J, Cook, Gordon, Quach, H, Venner, Christopher P., Cavo, M, Ngo, Mai, Bolyard, Kasey, Carson, R, Borgsten, Fredrik, Mateos, María‐Victoria , Kumar, Shaji , Miguel, Jesús F. San , Bahlis, Nizar Jacques , San-Miguel, Jesus , Zweegman, Sonja , Perrot, Aurore , Manier, Salomon , Orlowski, Robert Z. , Goldschmidt, Hartmut , Mohty, Mohamad , Leleu, Xavier , Cook, Gordon , Quach, Hang , Mateos, María-Victoria , Kumar, Shaji K , Facon, Thierry T.F. , Usmani, Saad Z. , Dimopoulos, Meletios A , Moreau, Philippe , Chari, Ajai , Goldschmidt, Hartmut , Basu, Supratik , Hulin, Cyrille , Weisel, Katja C , Mohty, Mohamad , Leleu, Xavier , Jakubowiak, Andrzej , Cook, Gordon , Quach, Hang , Cavo, M., Carson, Robin

Blood Advances | May 5, 2026 | Volume: 10 | Issue: 13 | Pages: 4541-4550

10.1182/bloodadvances.2025019323 | PMID 42085642 Get It

Abstract Both the phase 3 MAIA and ALCYONE studies demonstrated significant survival benefit with the addition of daratumumab to standard-of-care Rd (Revlimid [lenalidomide] and dexamethasone; D-Rd) or to VMP (Velcade [bortezomib], melphalan, and prednisone; D-VMP), respectively, vs Rd or VMP alone in transplant-ineligible newly diagnosed multiple myeloma (NDMM). Patients with NDMM are highly susceptible to infection; therefore, gaining a greater understanding of infection incidence may help to mitigate future risk. We conducted a pooled analysis of infection incidence, timing, and management strategies from MAIA and ALCYONE. The median (range) age of the pooled population was 72 (40-93) years. Incidence was higher with D-Rd/D-VMP vs Rd/VMP for grade 3/4 (36.9% vs 22.4%) and grade 5 (3.0% vs 1.5%) infections; however, exposure-adjusted incidence rates were generally comparable between groups. Any-grade infections led to the discontinuation of study treatment in ∼2% of patients across treatment groups. Of the timing intervals explored, the highest incidence of grade 3/4 infection occurred within the first 6-month interval of study treatment initiation in both groups. Median time to the first onset of grade 3/4 infections (per Kaplan-Meier estimates) was 83.3 months and not estimable in the D-Rd/D-VMP and Rd/VMP groups, respectively. Although the rates of D-Rd/D-VMP treatment discontinuation due to infection remained low in MAIA and ALCYONE, clinicians should remain vigilant about infections throughout treatment and follow local guidelines and International Myeloma Working Group recommendations to minimize the risk of infection. These trials were registered at www.ClinicalTrials.gov as NCT02252172 (MAIA) and NCT02195479 (ALCYONE).
Review of the first on-body injector (OBI) for the subcutaneous delivery of an oncology drug: isatuximab in multiple myeloma
Ocio, E. M., Parmar, Gurdeep , Mateos, María-Victoria, Leleu, Xavier, Buck, Tondre T., Tan, Carlyn Rose, Curry, Nicole C., Quach, Hang, K, E, Bobin, Arthur, Mohty, Mohamad, Ailawadhi, Sikander, Ocio, Enrique M. , Ocio, Enrique M , Mateos, María‐Victoria , Leleu, Xavier , Buck, Tondre, Curry, Nicole C., Ling, Silvia , Quach, Hang , Elias, K. , Bobin, Arthur , Mohty, Mohamad , Ailawadhi, Sikander , Moreau, Philippe

Expert Opinion on Drug Delivery | April 13, 2026 | Volume: 23 | Issue: 7 | Pages: 1289-1303

10.1080/17425247.2026.2659263 | PMID 41973697 Get It

Efficacy and safety of talquetamab + teclistamab in patients with Relapsed/Refractory multiple myeloma and extramedullary disease: Updated Phase 2 results from the redirectt-1 study with extended follow-up
Kumar, Shaji, Mateos, María‐Victoria , Ye, J Christine, Magen, Hila , Trudel, Suzanne , Richter, Joshua R. , Chuah, Hun , Yoon, Dok Hyun, Matous, Jeffrey, Dachs, Laura Rosiñol, Onodera, Koichi , Maffucci, Carmela, Heuck, Christoph, Henninger, Todd, O’Rourke, Lisa, Thakkar, Payal, Festa, M, Zhou, Jiangxiu, Takamoto, Mikihiro, Pei, Lixia, Lu, Jiashen, Au, Nicholas T., Krevvata, Maria, Cohen, Yaël C. , Usmani, Saad Z. , Kumar, Shaji , Atrash, Shebli , Quach, Hang , Chu, Michael, Rodríguez‐Otero, Paula , Gatt, Moshe E. , Medvedova, Eva , Raza, Shahzad , Yoon, Dok Hyun , Ishida, Tadao , Scott, Emma , Zhang, Jing , Festa, Mariacristina, Huang, Lin , Lu, Jiashen

Blood | December 5, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 698-698

10.1182/blood-2025-698 Get It

Abstract Introduction: Patients (pts) with soft tissue plasmacytomas noncontiguous with bone (true extramedullary disease [EMD]) have poor outcomes with standard therapies shown by low overall response rates (ORRs), which are not durable. Talquetamab (Tal; anti-GPRC5D×CD3) and teclistamab (Tec; anti-BCMA×CD3) are first-in-class bispecific antibodies (BsAbs) approved as monotherapies for triple-class exposed (TCE) relapsed/refractory multiple myeloma (RRMM). Primary analysis from the RedirecTT-1 (NCT04586426) dedicated phase 2 EMD cohort (March 2025 data cut; median follow-up [mFU] 12.6 mo) showed Tal + Tec elicited an ORR of 78.9% (assessed by independent review committee) and a 12-mo progression-free survival (PFS) of 61.0%. Here, we report updated efficacy, using investigator assessment, and safety results from the phase 2 RedirecTT-1 EMD cohort with Tal + Tec. Importantly, we report EMD location and a novel analysis of tumor burden as a prognostic indicator of ORR. Methods: Pts had TCE RRMM and true EMD defined as ≥1 nonradiated soft tissue plasmacytoma noncontiguous with bone ≥2 cm in 1 dimension (with or without paramedullary plasmacytomas). Nonsecretory/oligosecretory disease was permitted. Prior CAR-T and non-BCMA/-GPRC5D BsAb therapies were permitted. Pts received Tal 0.8 mg/kg + Tec 3.0 mg/kg Q2W, preceded by step-up doses, with a permitted switch to monthly dosing at investigator's discretion after cycle 6 or after cycle 4 with confirmed ≥VGPR. Response was assessed per IMWG; EMD response was assessed by PET-CT or MRI whole-body scans. Tumor burden was assessed by total EMD tumor volume. Results: As of July 2025, 90 pts received Tal + Tec, with a median follow-up of 16.3 mo (range 0.5–23.7). Baseline characteristics were as previously reported; 39% had nonsecretory/oligosecretory disease, 20% had prior anti-BCMA CAR-T therapy, and 9% had prior BsAb therapy (all anti-FcRH5). The median number of plasmacytomas was 2 (range 1–7); 17 (18.9%), 29 (32.2%), and 74 (82.2%) pts, respectively, had ≥1 nodal, organ, or soft tissue EMD, while 11 (12.2%) also had ≥1 additional paramedullary plasmacytoma. Of 268 EMDs across all pts, 95 (35.4%) were nodal EMD, 77 (28.7%) were organ EMD (most commonly liver), and 64 (23.9%) were soft tissue EMD; 32 (11.9%) were paramedullary. Baseline EMD tumor volume was <25 cm2in 43 (47.8%) pts, 25–50 cm2 in 21 (23.3%) pts, and >50 cm2 in 26 (28.9%) pts. Per investigator assessment, ORR (95% CI) was 77.8% (67.8–85.9); 50.0% had a ≥CR. Median duration of response (DOR) was not estimable (NE; 12-mo DOR rate, 60.1%), 12-mo PFS was 55.6%, and median overall survival (OS) was NE (12-mo OS rate 73.8%). ORR was 90.7% (77.9–97.4; ≥CR 60.5%) in pts with EMD tumor volume <25 cm2, 66.7% (43.0–85.4; ≥CR 52.4%) for 25–50 cm2, and 65.4% (44.3–82.8; ≥CR 30.8%) for >50 cm2. Common adverse events (AEs) included CRS (77.8%; no grade [gr] 3/4) and neutropenia (72.2%; gr 3/4 62.2%). Taste changes (78.9%), non-rash skin AEs (68.9%), and nail AEs (55.6%) were all gr 1/2, and rash AEs (30.0%) were mostly gr 1/2. ICANS occurred in 11 (12.2%) pts (gr 3, 1.1%; gr 4, 1.1%). Infections occurred in 72 (80.0%) pts (gr 3/4 40.0%), most commonly upper respiratory tract infection (26.7%; gr 3/4 5.6%); IVIG was highly recommended to prevent and manage hypogammaglobulinemia and infection. Ten (11.1%) pts discontinued Tal + Tec due to treatment-emergent AEs (4 pts due to infections and 6 due to gr 5 AEs). Two pts discontinued Tal only due to AEs. In total, 11 (12.2%) pts had gr 5 AEs (6 due to infections), 6 of which were deemed to be drug related by investigators. Data will be updated with an additional 4 mo of follow-up for the presentation. Conclusions: With longer follow-up in pts with TCE RRMM with true EMD regardless of baseline tumor characteristics, Tal + Tec efficacy exceeded all approved therapies, including T-cell redirecting and cellular therapies, noting limitations of cross-study comparisons. Lower total EMD tumor volume was associated with a higher ORR but low pt numbers in each group and lack of statistical testing limits robust interpretation. The safety profile of Tal + Tec was generally consistent with each monotherapy; AEs were not exacerbated with the combination. These data continue to highlight the clinical benefit of the novel combination of Tal + Tec in pts with true EMD, a population with high disease burden and significant unmet need.
Low Measles Seropositivity in Vaccinated Children
Jones, Sara Pace, Joseph, Iype, Powell, Alexandria J., Ovsyannikova, Inna G. , Warner, Nathaniel D. , Grill, Diane E. , Sasi, Remya Vasanthi, Ajithakumari, Archana Mohankumar, Prasad, Raji, Reveendran, Remya, Devakikutty, Jayalekshmi, Mohanakumari, Vishnu Vikraman, Poland, Gregory A., Pillai, M. Radhakrishna , Jacob, Joshy , Quach, Huy Quang , Kennedy, Richard B. , Jones, Sara P., Powell, Alexandria J., Johnson, John Bernet , Mohanakumari, Vishnu VikramanThampi, Poland, Gregory A.

JAMA Network Open | August 27, 2025 | Volume: 8 | Issue: 8 | Pages: e2529409

10.1001/jamanetworkopen.2025.29409 | PMID 40864465 Get It

ImportanceIndia’s goal of measles elimination remains unmet, as evidenced by significant recent outbreaks.ObjectiveTo identify seroprevalence rates among vaccinated children and to examine demographic factors that influence antibody responses.Design, Setting, and ParticipantsThis cross-sectional study included a highly vaccinated cohort of Indian children from the states of Kerala and Tamil Nadu between 2018 and 2023. Eligible children had received at least 2 doses of measles-containing vaccines; their mothers were recruited from various community settings, including local nursery and secondary schools, residential associations, and hospitals.ExposureMeasles-specific antibodies were quantified in serum samples.Main Outcomes and MeasuresMeasles-specific immunoglobulin G (IgG) and neutralizing antibodies were quantified in both children and mothers. Measles-specific IgM was also measured in children.ResultsThe total cohort comprised 684 children (median age, 9 years [range, 4-18 years]; 348 male [50.1%]) and 544 mothers. All children received at least 2 doses of measles-containing vaccines; 435 children (63.6%) received a third dose, and 7 (1.0%) received a fourth dose. Among the children, 621 (90.8%) had positive measles-specific IgG, and 623 (91.5%) had protective neutralizing antibodies titers, with a strong correlation between measles-specific IgG and neutralizing antibodies (r = 0.73; P < .001). Female children exhibited significantly higher titers of both measles-specific IgG and neutralizing antibodies compared with male children. While IgG and neutralizing antibody titers remained stable over time and were not associated with the number of vaccine doses in children, neutralizing antibody titers increased with age in mothers, likely due to repeated viral exposure. Notably, in 20 families with at least 2 children, differential measles-specific IgM profiles were observed between siblings despite high IgG and neutralizing antibody titers, suggesting ongoing breakthrough infections.Conclusions and RelevanceIn this cross-sectional study, substantial measles immunity gaps were found despite high vaccine coverage with evidence of breakthrough infections, posing significant challenges to India’s measles elimination efforts. These results underscore the urgent need to strengthen India’s immunization program and investigate the mechanisms driving suboptimal responses to measles vaccination; without addressing these immune response deficiencies, achieving measles elimination through increased vaccine coverage alone may remain unattainable in India.
The Evolving Treatment Landscape for the Elderly Multiple Myeloma Patient: From Quad Regimens to T-Cell Engagers and CAR-T
Rees, Matthew J. , Rees, Matthew James , Quach, Hang

Cancers | August 5, 2025 | Volume: 17 | Issue: 15 | Pages: 2579

10.3390/cancers17152579 | PMID 40805272 Get It

Multiple myeloma (MM) is predominantly a disease of the elderly. In recent years, a surge of highly effective plasma cell therapies has revolutionized the care of elderly multiple myeloma (MM) patients, for whom frailty and age-related competing causes of mortality determine management. Traditionally, the treatment of newly diagnosed elderly patients has centered on doublet or triplet combinations composed of immunomodulators (IMIDs), proteasome inhibitors (PIs), anti-CD38 monoclonal antibodies (mAbs), and corticosteroids producing median progression-free survival (PFS) rates between 34 and 62 months. However, recently, a series of large phase III clinical trials examining quadruplet regimens of PIs, IMIDs, corticosteroids, and anti-CD38 mAbs have shown exceptional outcomes, with median PFS exceeding 60 months, albeit with higher rates of peripheral neuropathy (≥Grade 2: 27% vs. 10%) when PIs and IMIDs are combined, and infections (≥Grade 3: 40% vs. 29–41%) with the addition of anti-CD38mAbs. The development of T-cell redirecting therapies including T-cell engagers (TCEs) and CAR-T cells has further expanded the therapeutic arsenal. TCEs have shown exceptional activity in relapsed disease and are being explored in the newly diagnosed setting with promising early results. However, concerns remain regarding the logistical challenges of step-up dosing, which often necessitates inpatient admission, the infectious risks, and the financial burden associated with TCEs in elderly patients. CAR-T, the most potent commercially available therapy for MM, offers the potential of a ‘one and done’ approach. However, its application to elderly patients has been tempered by significant concerns of cytokine release syndrome, early and delayed neurological toxicity, and its overall tolerability in frail patients. Robust data in frail patients are still needed. How CAR-T and TCEs will be sequenced among the growing therapeutic armamentarium for elderly MM patients remains to be determined. This review explores the safety, efficacy, cost, and logistical barriers associated with the above treatments in elderly MM patients.
Allele-specific vitamin D receptor binding is associated with pediatric-onset multiple sclerosis
Yilmaz, Defne , Adams, Cameron , Francisco, Carla , Rutatangwa, Alice , Quach, Hong , Quach, Diana , Aaen, Gregory , Lotze, Timothy , Mar, Soe , Ness, Jayne , Wheeler, Yolanda , Gorman, Mark , Schreiner, Teri , Tillema, Jan-Mendelt , Rose, John , Casper, T. Charles , Barcellos, Lisa F. , Edwards, Alice Rutatangwa , Benson, Leslie A , Weinstock‐Guttman, Bianca , Schreiner, Teri , Rensel, Mary R. , Horton, Mary , Graves, Jennifer , Benson, Leslie , Waldman, Amy , Tillema, Jan‐Mendelt , Chitnis, Tanuja , Waubant, Emmanuelle L.

Multiple Sclerosis Journal – Experimental, Translational and Clinical | May 27, 2025 | Volume: 11 | Issue: 2 | Pages: No page available

10.1177/20552173251335625 | PMID 40438528 Get It

Background and Objectives The genetic basis of adult-onset multiple sclerosis (MS) is well-studied, but less is known about pediatric-onset MS (pedMS), comprising approximately 5% of all MS onsets. Mendelian randomization (MR) studies have demonstrated evidence for a causal association between MS and both 25-hydroxyvitamin D [25(OH)D] serum levels and genetic variation related to vitamin D receptor (VDR) binding. The objective was to identify whether VDR binding variants (VDR-BVs) previously implicated in adult-onset MS were associated with pedMS using genetic instrumental variables (GIVs). Methods Using previously identified VDR-BVs to construct individual GIVs with two-sample MR, we investigated associations with pedMS in 725 cases and 592 controls of European ancestry from the US Network of Pediatric MS Centers. Associations between each VDR-BV and pedMS were estimated using logistic regression adjusting for the first three genome-wide principal components. A significant interaction between a VDR-BV and 25(OH)D GIV provided evidence for a causal association unbiased by pleiotropy. Results One VDR-BV, rs2531804, previously associated with adult-onset MS, was also significantly associated with pedMS after multiple testing correction. Discussion This study is the first to use VDR-BVs from previous MR studies to demonstrate causal differences in VDR binding at a locus contributing to pedMS susceptibility.