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NKTR-255

Phase 1

Head and Neck Squamous Cell Carcinoma | Small molecule | Oncology |Nektar Therapeutics|Last Updated: Jun 8, 2025

Success Probability

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Market & Valuation

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Trial Design

UNCONTROLLEDDMC
Total Trials1
Total Enrollment25

FDA Designations

No designations recorded

Clinical trial landscape

NKTR-255 · 2 trials · 5 indications

Phase 1 2
NCT04616196Study of NKTR 255 in Combination With Cetuximab in Solid TumorsHead and Neck Squamous Cell Carcinoma
COMPLETED25 Analytics
NCT04136756NKTR-255 in Relapsed/Refractory Multiple Myeloma & Non-Hodgkin LymphomaMultiple Myeloma
COMPLETED30 Analytics
PHASE1COMPLETED
Study of NKTR 255 in Combination With Cetuximab in Solid Tumors
Head and Neck Squamous Cell CarcinomaUnlock trial analytics
PHASE1COMPLETED
NKTR-255 in Relapsed/Refractory Multiple Myeloma & Non-Hodgkin Lymphoma
Multiple MyelomaUnlock trial analytics

Study Endpoints

Primary Endpoints

Incidence of Treatment-Emergent Adverse Events (TEAE) and Serious Adverse Events (SAE) of NKTR-255 in Combination With Cetuximab in R/R HNSCC or CRC for Phase 1b Dose Escalation
60 days after the last dose of study treatment, up to an average of 6 months.

Safety and tolerability of NKTR-255 in combination with cetuximab as evaluated by dose limiting toxicities, incidence of drug-related Adverse Events (AEs), SAEs, and AEs leading to discontinuation, deaths, and clinical laboratory abnormalities per CTCAE 5.0

The Maximum Tolerated Dose (MTD) and/or Recommended Phase 2 Dose (RP2D) of NKTR-255 in Combination With Cetuximab in R/R HNSCC or CRC for Phase 1b Dose Escalation
Up to 21 days

To define the MTD and/or RP2D of NKTR-255 in combination with cetuximab in R/R HNSCC or CRC for Phase 1b Dose Escalation

Incidence of Treatment-Emergent Adverse Events and Serious Adverse Events of NKTR-255 as a single agent
Through study completion, an expected average of 6 months

Safety and tolerability of NKTR-255 as evaluated by incidence of Dose Limiting Toxicities (DLTs), drug-related Adverse Events (AEs), Serious Adverse Events (SAEs), AEs leading to discontinuation, deaths, clinical laboratory abnormalities per CTCAE v5.

Incidence of Treatment-Emergent Adverse Events and Serious Adverse Events of NKTR-255 with daratumumab SC
Through study completion, an expected average of 1 year

Safety and tolerability of NKTR-255 in combination with daratumumab as evaluated by incidence of drug-related AEs, SAEs, AEs leading to discontinuation, deaths, clinical laboratory abnormalities per CTCAE v5

Incidence of Treatment-Emergent Adverse Events and Serious Adverse Events of NKTR-255 with rituximab
Through study completion, an expected average of 1 year

Safety and tolerability of NKTR-255 in combination with rituximab as evaluated by incidence of drug-related AEs, SAEs, AEs leading to discontinuation, deaths, clinical laboratory abnormalities per CTCAE v5

Evaluate the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D) of NKTR-255 as a single agent
Through study completion, an expected average of 6 months
Evaluate the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D) of NKTR-255 in combination with daratumumab SC
Through study completion, an expected average of 1 year
Evaluate the maximum tolerated dose (MTD) and recommended Phase 2 dose (RP2D) of NKTR-255 in combination with rituximab
Through study completion, an expected average of 1 year
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Study Design & Arms

AllocationNA
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Dose Escalation of NKTR-255 with CetuximabEXPERIMENTALEstablish RP2D, of NKTR-255 with cetuximab.
Dose EscalationEXPERIMENTALEvaluation of NKTR-255 as: * Monotherapy * In combination with daratumumab * In combination with rituximab This phase will help to determine the RP2D of NKTR-255
Dose Expansion Cohort AEXPERIMENTALEvaluation of RP2D of NKTR-255 as monotherapy in patients with NHL relapsed after CAR-T
Dose Expansion Cohort BEXPERIMENTALEvaluation of RP2D of NKTR-255 as monotherapy and in combination with SC daratumumab in patients with R/R MM
Dose Expansion Cohort CEXPERIMENTALEvaluation of RP2D of NKTR-255 as monotherapy and in combination with rituximab in patients with R/R iNHL

Interventions

NameTypeDescription
NKTR-255DRUGNKTR-255 IV every 21 days
CetuximabDRUGCetuximab will be given at specified doses on specified days
NKTR-255 Q21DRUGNKTR-255 administered by IV infusion every 21 days to establish safety and tolerability
RituximabDRUGRituximab administered intravenously at specified dose on specified days
DaratumumabDRUGDaratumumab administered subcutaneously at specified dose on specified days
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites6

Key Inclusion Criteria: * Histologically confirmed diagnosis of a locally advanced or metastatic HNSCC or CRC. * Life expectancy \> 12 weeks as determined by the Investigator. * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. * Measurable disease per RECIST 1.1. HNSCC: * Prog...

Countries:United States
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Frequently asked questions about NKTR-255

What is NKTR-255 used for?

NKTR-255 is an investigational oncology drug being studied for the treatment of Head and Neck Squamous Cell Carcinoma and Multiple Myeloma. It has also been evaluated in Non-Hodgkin Lymphoma and Colorectal Cancer in clinical trials. The drug is in Phase 1 clinical development and is not yet approved by regulatory authorities.

Who makes NKTR-255?

NKTR-255 is being developed by Nektar Therapeutics, a biopharmaceutical company traded on the NASDAQ under the ticker symbol NKTR. The company is conducting clinical trials to evaluate the safety and efficacy of this investigational drug in patients with certain types of cancer.

What phase is NKTR-255 in?

NKTR-255 is in Phase 1 clinical development. It is an investigational drug, meaning it has not been approved by the FDA or other regulatory agencies. The drug is being studied in early-stage clinical trials to assess its safety, tolerability, and preliminary efficacy in patients with cancer.

What clinical trials is NKTR-255 in?

NKTR-255 has been studied in two completed Phase 1 clinical trials. NCT04136756 evaluated the drug in patients with relapsed or refractory Multiple Myeloma and Non-Hodgkin Lymphoma, enrolling 30 participants. NCT04616196 studied NKTR-255 in combination with cetuximab in solid tumors, including Head and Neck Squamous Cell Carcinoma and Colorectal Cancer, enrolling 25 participants.

Is NKTR-255 the same as any other drug?

NKTR-255 is the primary name for this investigational drug. No alternative names have been reported for this asset. It is a small molecule being developed by Nektar Therapeutics for the treatment of certain cancers, including Multiple Myeloma and Head and Neck Squamous Cell Carcinoma.