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VX15/2503

Phase 2

Huntington's Disease | Small Molecules | Neurology |Vaccinex, Inc.|Trials Updated: Jul 16, 2026

VX15/2503 development status

Highest phase Phase 2
Registered trials 6 across 2 sponsors since Mar 2011

VX15/2503 target and mechanism

ModalitySmall Molecules

Also known as Pepinemab

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials4
Total Enrollment436

FDA Designations

No designations recorded

VX15/2503 clinical trials

VX15/2503 · 4 trials · 4 indications

Phase 2 1Phase 1/2 1Phase 1 2
NCT02481674A Study in Subjects With Late Prodromal & Early Manifest HD to Assess the Safety, Tolerability, pk, and Efficacy of PepiHuntington's Disease
COMPLETED301 Analytics
PHASE2COMPLETED
A Study in Subjects With Late Prodromal & Early Manifest HD to Assess the Safety, Tolerability, pk, and Efficacy of Pepi
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Study Endpoints

Primary Endpoints

Revisions to SAP were made prior to un-blinding, on June 30, 2020, upon consultation with FDA.
Prior to DBL/Study Completion

If primary outcome, listed below (Outcome 3), does not reach its critical p-value, the secondary outcomes will not be formally tested. If both co-primary outcomes are statistically significant, the five secondary outcomes will be formally tested following a hierarchical testing procedure.

Safety and tolerability of monthly intravenous (IV) administration of pepinemab relative to placebo in subjects with early HD (Cohort B pooled, includes Cohort B1 Early Manifest and Cohort B2 Late Prodromal HD).
Up to 18 months

Measured by drug related adverse event frequency and laboratory test abnormalities in all subjects.

Efficacy of monthly IV administration of pepinemab relative to placebo in Early Manifest HD (Cohort B1)
Up to 18 months

Co-primary outcome measured by the change from baseline in the Huntington's Disease Two-item Cognitive Family (PTAP and OTS) selected from the Huntington's Disease

Number of subjects with treatment emergent adverse events (TEAEs)
Up to 40 weeks

TEAEs are defined as Adverse events (AEs) with onset after date-time of first dose, or medical conditions present prior to the start of IP but increased in severity or relationship after date-time of first dose of IP.

Change in immune profile in the tumor microenvironment
Baseline up to 4-8 weeks after surgery

Specimens from surgical resection will be collected under the guidance of the collaborating pathologist and tissue procurement staff at the time of surgery to capture tissue in excess of that needed for clinical staging and diagnostic purposes. Tumor specimens will be fixed in 10% formalin, embedded in paraffin and biomarkers related to activated HNSCC stroma will be assessed via immunohistochemical analysis.

Change in circulating percentage of immune suppressor subsets in peripheral blood
Baseline up to 4-8 weeks after surgery

Blood samples will be collected and peripheral blood mononuclear cells will be isolated from these samples and stored in -80°C freezers until analysis. Multi-parameter flow cytometry will be utilized to phenotype immune effector cells. The impact of treatment on the circulating percentage of immune suppressor subsets that may serve as predictors of response to immune checkpoint inhibition. All data will be expressed as the percentage of total circulating peripheral blood cells with each respective phenotype.

Phenotypic shifts in T lymphocyte subsets in peripheral blood
Baseline up to 4-8 weeks after surgery

Blood samples will be collected and peripheral blood mononuclear cells will be isolated from these samples and stored in -80°C freezers until analysis. Blood will be analyzed by multi-parameter flow cytometry to identify systemic phenotypic shifts mediated by VX15/2503 in combination with immune checkpoint inhibition.

Safety/Tolerability as determined by number of patients with adverse events
Up to 12 weeks depending on dose cohort

Secondary Endpoints

Clinical feature of Early Manifest HD: motor function (Q-Motor)
Up to 18 months
Clinical feature of Early Manifest HD: functional capacity (UHDRS-TFC)
Up to 18 months
Clinical feature of Early HD: functional capacity (UHDRS-TFC)
Up to 18 months
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
VX15/2503EXPERIMENTALThe study drug VX15/2503 will be administered via monthly intravenous infusions
PlaceboPLACEBO_COMPARATORA placebo control will be administered via monthly intravenous infusions
pepinemab 40mg/kgEXPERIMENTALThe study drug, pepinemab, will be administered via monthly intravenous infusions.
Group A (VX15/2503)EXPERIMENTALPatients receive VX15/2503 IV over 60 minutes on day 1. Beginning days 17-36, patients undergo standard of care surgery.
Group B (VX15/2503, ipilimumab)EXPERIMENTALPatients receive VX15/2503 IV over 60 minutes and ipilimumab IV over 90 minutes on day 1. Beginning days 17-36, patients undergo standard of care surgery.
Group C (VX15/2503, nivolumab)EXPERIMENTALPatients receive VX15/2503 IV over 60 minutes and nivolumab IV over 60 minutes on day 1. Beginning days 17-36, patients undergo standard of care surgery.
Group D (nivolumab)EXPERIMENTALPatients receive nivolumab IV over 60 minutes on day 1. Beginning days 17-36, patients undergo standard of care surgery.
Group E (ipilimumab)EXPERIMENTALPatients receive ipilimumab IV over 90 minutes on day 1. Beginning days 17-36, patients undergo standard of care surgery.
Group F (no treatment)NO_INTERVENTIONPatients undergo standard of care surgery.

Interventions

NameTypeDescription
VX15/2503DRUGVX15/2503 (pepinemab) is a humanized IgG4 monoclonal antibody and will be administered intravenously at a dose of 20 mg/kg. The antibody is formulated at 20 mg/mL in 20 mM Sodium Acetate buffer, pH 5.4, containing 130 mM Sodium Chloride and 0.02% Polysorbate 80.
PlaceboDRUGPlacebo consists of formulation buffer only which is 20 mM Sodium Acetate buffer, pH 5.4, containing 130 mM Sodium Chloride and 0.02% Polysorbate 80.
PepinemabDRUGPepinemab is a humanized IgG4 monoclonal antibody. The antibody is formulated at 20 mg/mL in 20 mM Sodium Acetate buffer, pH 5.4, containing 130 mM Sodium Chloride and 0.02% Polysorbate 80
IpilimumabBIOLOGICALGiven IV
NivolumabBIOLOGICALGiven IV
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Eligibility Criteria

Age Range21 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites32

Inclusion Criteria Highlights: 1. Male or female and are at least greater than or equal to 21 years of age at Screening. 2. Must fulfill one of the following criteria at Screening: 1. Late prodromal HD as defined by a CAP score of greater than 200 and DCL 2 or 3. 2. Early manifest HD as defi...

Countries:United StatesCanada
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