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CDX-301

Phase 1

Healthy | Small molecule | Other |Celldex Therapeutics, Inc.|Last Updated: Mar 25, 2026

Target and mechanism

Molecular targetCD27
Target classProtein
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

UNCONTROLLED
Total Trials1
Total Enrollment30

FDA Designations

No designations recorded

Clinical trial landscape

CDX-301 · 2 trials · 3 indications

Phase 1 2
NCT04930783NeoVax + CDX-301 and Nivolumab or Pembrolizumab in MelanomaMelanoma
ACTIVE NOT_RECRUITING10 Analytics
NCT01465139A Study to Evaluate CDX-301 (rhuFlt3L) in Healthy VolunteersHealthy
COMPLETED30 Analytics
PHASE1ACTIVE NOT_RECRUITING
NeoVax + CDX-301 and Nivolumab or Pembrolizumab in Melanoma
MelanomaUnlock trial analytics
PHASE1COMPLETED
A Study to Evaluate CDX-301 (rhuFlt3L) in Healthy Volunteers
HealthyUnlock trial analytics

Study Endpoints

Primary Endpoints

Rate of Dose Limiting Toxicity (DLT)
Toxicities experienced within 49 days/7 weeks of Neoantigen Vaccine treatment initiation

Based on the CTEP Active Version (version 5.0) of the NCI Common Terminology Criteria for Adverse Events (CTCAE).

Recommended maximum tolerated dose (MTD)
Up to 12 weeks for each dosing cohort

Highest dose of CDX-301 that did not cause a dose limiting toxicity

Number of reported adverse events
Until day 28 of follow up.

The number of adverse events along with the results of vital sign measurements, physical examinations, and clinical laboratory tests will be used to determine the safety profile of CDX301.

Secondary Endpoints

Neoantigen-specific cellular immune responses
Enrollment to end of treatment up to 24 weeks
Estimate rates of disease progression/recurrence depending on whether patient had all melanoma resected or has measurable disease per RECIST 1.1
Enrollment to end of treatment up to 24 weeks
Determination of PK profile of CDX301
Until day 28 of follow up or until resolution.
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSINGLE_GROUP
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
CDX-301 + Neovax + NivolumabEXPERIMENTAL* Participants will have vaccine made from tissue collected from metastatic tumor biopsy or surgical resection, or from previously collected archival biopsy or surgical tissue. * Participants will receive Nivolumab at a flat dose every 4 weeks up to two years. * Participants will receive CDX-301 at a predetermined dose dependent on the number of participants previously enrolled for 5 days starting 2 days before the initiation of NeoVax. CDX-301 will then be administered at a predetermined dose dependent on the number of participants previously enrolled 2 days before and for 5 days coinciding with the administration of NeoVax on days 50 and 78.
CDX-301 + Neovax + PembrolizumabEXPERIMENTAL* Participants will have vaccine made from tissue collected from tumor biopsy, or from previously collected archival biopsy or surgical tissue. * Participants will receive neoadjuvant Pembrolizumab for 3 doses every 3 weeks, then undergo standard-of-care surgical resection. * Participants will receive adjuvant NeoVax and CDX-301. CDX-301 will be administered at a predetermined dose, dependent on the number of participants previously enrolled, for 5 days starting 2 days before the initiation of NeoVax. CDX-301 will then be administered at a predetermined dose dependent on the number of participants previously enrolled 2 days before and for 5 days coinciding with the administration of NeoVax on days 50 and 78. * Participants will receive adjuvant Pembrolizumab for 15 doses every 6 weeks.
CDX-301EXPERIMENTALCDX-301 (rhuFlt3L), administered to healthy patients.

Interventions

NameTypeDescription
CDX-301DRUGAdministered as an injection given underneath the skin
NEOVAXBIOLOGICALPersonalized neoantigen vaccine administered as an injection given underneath the skin
NivolumabDRUGAdministered intravenously (IV)
PembrolizumabDRUGAdministered intravenously (IV)
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites1

Inclusion Criteria: Eligibility to participate will be assessed at one timepoint: prior to initial core needle/surgical biopsy (Initial Registration). * Inclusion Criteria * Participant is willing and able to give written informed consent * Participants must have histologically confirmed stag...

Countries:United States
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Frequently asked questions about CDX-301

What is CDX-301 used for?

CDX-301 is an investigational small molecule being studied for use in melanoma and in healthy volunteers. It is being evaluated in Phase 1 clinical trials, including a study combining it with NeoVax and nivolumab or pembrolizumab in patients with metastatic melanoma.

What does CDX-301 target?

CDX-301 targets CD27, a protein involved in immune cell signaling. By targeting CD27, CDX-301 may modulate immune responses, which is relevant to its investigation in melanoma and as a potential immunotherapeutic agent.

Who is developing CDX-301?

CDX-301 is being developed by Celldex Therapeutics, Inc., a biopharmaceutical company traded on the NASDAQ under the ticker symbol CLDX. The company is conducting Phase 1 clinical trials to evaluate the drug's safety and potential efficacy.

What phase is CDX-301 in?

CDX-301 is in Phase 1 clinical development. It is not yet approved by the FDA and remains investigational. Two Phase 1 trials have been conducted: one completed in healthy volunteers and one active but not recruiting in melanoma patients.

What clinical trials is CDX-301 in?

CDX-301 has been studied in two Phase 1 trials. NCT01465139 evaluated CDX-301 in healthy volunteers and is completed. NCT04930783 is an active, not recruiting trial combining CDX-301 with NeoVax and nivolumab or pembrolizumab in patients with metastatic melanoma.

Is CDX-301 the same as rhuFlt3L?

Yes, CDX-301 is also known as rhuFlt3L, as indicated in the title of the completed healthy volunteer trial NCT01465139. This alternative name refers to the recombinant human Flt3 ligand, which is the active component of CDX-301.