A Phase 2/3 interventional study of NKTR-255 at 1.5 µg/kg and NKTR-255 at 3.0 μg/kg in Non-Hodgkin Lymphoma and Relapsed/Refractory Diffuse Large B-cell Lymphoma, sponsored by Nektar Therapeutics. Terminated at 7 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by Nektar Therapeutics · Phase 2/3, Interventional, and Treatment
Nektar Study 18-255-01 was a Phase 2/3, randomized, double blind, placebo-controlled, multicenter study of NKTR-255 versus placebo following CD19-directed CAR-T cell therapy in patients with R/R LBCL. This study was to be run in 2 parts: Phase 2 (Stage 1) and Phase 3 (Stage 2).
This study evaluated the safety and efficacy of NKTR-255 following CD19-directed chimeric antigen (CAR)-T cell therapy in patients with relapsed or refractory (R/R) large B-cell lymphoma (LBCL).
NKTR-255 was an investigational IL-15 receptor agonist designed to boost the immune system's natural ability to fight cancer. T cells are infection fighting blood cells that can kill tumor cells. Chimeric antigen (CAR)-T cell product consists of genetically engineered T-cells, modified to recognize CD19, a protein on the surface of cancer cells. These CD19-specific T cells may help the body's immune system identify and kill CD19-positive cancer cells. Giving NKTR-255 following the treatment with CD19 CAR-T cell therapy may work better in treating large B-cell lymphoma than either drug alone.
Patients were treated with lymphodepletion chemotherapy (as recommended by the CAR-T cell manufacturer) and soon after received a one-time CD19-directed CAR-T cell infusion (as per product label). Study drug (NKTR-255 or placebo) was administered intravenously approximately 14 days after CAR-T cell infusion and administered every 3 weeks for up to 7 cycles or 5 months (whichever was earlier) in the absence of disease progression or unacceptable toxicity.
During Stage 1, Nektar made the decision to close the study at all sites.
1,868 studies on the registry are indexed under Lymphoma, Large B-Cell, Diffuse; 355 are open to participants now.
This study's enrollment of 15 is below the median of 45 across 1,497 interventional studies indexed under Lymphoma, Large B-Cell, Diffuse.
Browse Lymphoma, Large B-Cell, Diffuse studies →Nektar Therapeutics is the lead sponsor of 39 studies on the registry; 2 are open to participants now.
Of its 22 completed or terminated interventional studies of FDA-regulated products, 13 (59%) have results posted.
Compared within Lymphoma, Large B-Cell, Diffuse, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Lymphoma, Non-Hodgkin. The counts are of registry records indexed under each term, refreshed daily. How we classify →
The criteria were revised on the registry on Oct 16, 2026. See what changed
Key Inclusion Criteria:
Received standard of care therapy with axi-cel or liso-cel for the respective FDA (or Summary of Product Characteristics [SmPC]) approved indication(s):
liso-cel: Patients with LBCL (including diffuse LBCL [DLBCL] not otherwise specified [including DLBCL arising from indolent lymphoma], high-grade B-cell lymphoma, primary mediastinal LBCL, and follicular lymphoma Grade 3B), who have:
axi-cel: For the treatment of adult patients with LBCL that is:
Regarding prior systemic anti-tumor therapy:
Adequate organ function, defined as:
Able and willing to comply with study visit schedule and procedures, including tumor where accessible.
Additional Eligibility Criteria Following CD19 Targeted CAR-T Cell Infusion
Patients who have received commercially released CAR-T cell infusion must satisfy the following criteria on the day of randomization:
Patients must satisfy the following laboratory test results:
Exclusion Criteria:
Active or inflammatory disorders (including inflammatory bowel disease [eg, ulcerative colitis, Crohn's disease], celiac disease, or other serious chronic gastrointestinal conditions associated with diarrhea, autoimmune vasculitis, systemic lupus erythematosus, Wegener syndrome [granulomatosis with polyangiitis], myasthenia gravis, Graves' disease, rheumatoid arthritis, hypophysitis, uveitis, etc.) within 1 year prior to randomization. The following are exceptions to this criterion:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
FEV1
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GVHD (graft-versus-host disease)
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Brain metastases
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
In this arm of Stage 1 (Phase 2 of the study), NKTR-255 was dosed at 1.5 µg/kg. NKTR-255 was administered intravenously approximately 14 days after CD19-directed CAR-T cell infusion. Patients were dosed every 3 weeks for up to 7 cycles or 5 months, whichever was earlier, in the absence of disease progression or unacceptable toxicity.
Drug: NKTR-255 at 1.5 µg/kg
In this arm of Stage 1 (Phase 2 of the study), NKTR-255 was dosed at 3.0 μg/kg. NKTR-255 was administered intravenously approximately 14 days after CD19-directed CAR-T cell infusion. Patients were dosed every 3 weeks for up to 7 cycles or 5 months, whichever was earlier, in the absence of disease progression or unacceptable toxicity.
Drug: NKTR-255 at 3.0 μg/kg
In this arm of Stage 1 (Phase 2 of the study), patients were dosed with 3.0 μg/kg NKTR-255 in Cycle 1 (C1) and continue in Cycle 2 and subsequent cycles (C+) with 6.0 μg/kg NKTR-255 (hereinafter referred to as 3.0/6.0 µg/kg NKTR-255). NKTR-255 was administered intravenously approximately 14 days after CD19-directed CAR-T cell infusion. Patients were dosed every 3 weeks for up to 7 cycles or 5 months, whichever was earlier, in the absence of disease progression or unacceptable toxicity.
Drug: NKTR-255 at 3.0/6.0 μg/kg
Placebo was commercially available 0.9% Sodium Chloride Solution for Injection (USP). Placebo was administered intravenously approximately 14 days after CD19-directed CAR-T cell infusion. Placebo was infused every 3 weeks for up to 7 cycles or 5 months, whichever was earlier.
Other: Placebo Comparator
Drug page: NKTR-255
NKTR-255 at 1.5 µg/kg
Also known as: Polymer-conjugated interleukin (IL)-15 Receptor Agonist
Drug page: NKTR-255
NKTR-255 at 3.0 μg/kg
Also known as: Polymer-conjugated interleukin (IL)-15 Receptor Agonist
Drug page: NKTR-255
NKTR-255 at 3.0/6.0 μg/kg
Also known as: Polymer-conjugated interleukin (IL)-15 Receptor Agonist
Commercially available 0.9% Sodium Chloride Solution for Injection (USP)
Complete Response (CR) Rate
The incidence of complete response by the Lugano Classification (Cheson et al, 2014) as determined by blinded independent central review (BICR)
Time frame: At month 6
Number of Patients With at Least One (1) Treatment-emergent Adverse Events (AEs)
Time frame: From the first dose of study drug up to 30 days after the last dose of study drug, average of 1 year
Complete Response (CR) Rate
The incidence of complete response at month 3 by the Lugano Classification (Cheson et al, 2014) as determined by blinded independent central review (BICR)
Time frame: At month 3
Best Overall Complete Response (CR) Rate
The incidence of complete response in study by the Lugano Classification (Cheson et al, 2014) as determined by blinded independent central review (BICR)
Time frame: Approximately 1 year and 5.5 months
Objective Response Rate (ORR)
The incidence of objective response rate is defined as the incidence of either a complete response or a partial response by the Lugano Classification (Cheson et al, 2014) as determined by BICR
Time frame: At month 3
Objective Response Rate (ORR)
The incidence of objective response rate is defined as the incidence of either a complete response or a partial response by the Lugano Classification (Cheson et al, 2014) as determined by BICR
Time frame: At month 6
Best Overall Objective Response Rate (ORR)
The incidence of objective response rate in study is defined as the incidence of either a complete response or a partial response by the Lugano Classification (Cheson et al, 2014) as determined by BICR
Time frame: Approximately 1 year and 5.5 months
Duration of Response (DOR)
The duration of response is derived only among subjects who experience an objective response per Lugano Classification (Cheson et al, 2014) as determined by blinded central review and is defined as the time from first response to disease progression per the Lugano Classification or death from any cause
Time frame: Approximately 1 year and 5.5 months
Overall Duration of Progression-Free Survival (PFS)
Progression Free Survival is defined as the time from randomization to disease progression per Lugano Classification (Cheson et al, 2014) or death from any cause
Time frame: Approximately 1 year and 5.5 months
Overall Survival (OS)
Overall survival is defined as the time from randomization to death from any cause
Time frame: Approximately 1 year and 5.5 months
Event-free Survival (EFS)
Event-free survival is defined as the time from randomization to the earliest date of disease progression by the Lugano Classification (Cheson et al, 2014) as determined by BICR, commencement of new lymphoma therapy, or death from any cause.
Time frame: At 3, 6 and 9 months
Fifteen (15) patients were enrolled and received at least 1 dose of study drug. No patients were enrolled in Stage 2 as the study was terminated during Stage 1. * First patient registered: 23 February 2023 * Last patient, last visit: 16 August 2024
| Milestone | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo |
|---|---|---|---|---|
| Started | 5 | 3 | 3 | 4 |
| Completed | 2 | 2 | 2 | 2 |
| Not completed | 3 | 1 | 1 | 2 |
| Withdrew: Adverse event | 2 | 1 | 0 | 0 |
| Withdrew: Progressive disease | 0 | 0 | 1 | 1 |
| Withdrew: Physician decision | 1 | 0 | 0 | 1 |
The incidence of complete response by the Lugano Classification (Cheson et al, 2014) as determined by blinded independent central review (BICR)
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Complete Response (CR) Rate | 4 | 2 | 2 | 8 | 2 |
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Number of Patients With at Least One (1) Treatment-emergent Adverse Events (AEs) | 4 | 3 | 3 | 10 | 4 |
The incidence of complete response at month 3 by the Lugano Classification (Cheson et al, 2014) as determined by blinded independent central review (BICR)
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Complete Response (CR) Rate | 3 | 2 | 2 | 7 | 2 |
The incidence of complete response in study by the Lugano Classification (Cheson et al, 2014) as determined by blinded independent central review (BICR)
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Best Overall Complete Response (CR) Rate | 4 | 2 | 2 | 8 | 3 |
The incidence of objective response rate is defined as the incidence of either a complete response or a partial response by the Lugano Classification (Cheson et al, 2014) as determined by BICR
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo |
|---|---|---|---|---|
| Objective Response Rate (ORR) | 4 | 2 | 2 | 3 |
The incidence of objective response rate is defined as the incidence of either a complete response or a partial response by the Lugano Classification (Cheson et al, 2014) as determined by BICR
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo |
|---|---|---|---|---|
| Objective Response Rate (ORR) | 4 | 2 | 2 | 3 |
The incidence of objective response rate in study is defined as the incidence of either a complete response or a partial response by the Lugano Classification (Cheson et al, 2014) as determined by BICR
| Participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo |
|---|---|---|---|---|
| Best Overall Objective Response Rate (ORR) | 4 | 2 | 3 | 3 |
The duration of response is derived only among subjects who experience an objective response per Lugano Classification (Cheson et al, 2014) as determined by blinded central review and is defined as the time from first response to disease progression per the Lugano Classification or death from any cause
| years | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Duration of Response (DOR) | NA (NA to NA) | NA (NA to NA) | NA (NA to NA) | NA (NA to NA) | NA (NA to NA) |
Progression Free Survival is defined as the time from randomization to disease progression per Lugano Classification (Cheson et al, 2014) or death from any cause
| months | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Overall Duration of Progression-Free Survival (PFS) | NA (1.94 to NA) | NA (NA to NA) | NA (NA to NA) | NA (1.94 to NA) | NA (2.83 to NA) |
Overall survival is defined as the time from randomization to death from any cause
| months | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Overall Survival (OS) | NA (1.94 to NA) | NA (NA to NA) | NA (NA to NA) | NA (1.94 to NA) | NA (NA to NA) |
Event-free survival is defined as the time from randomization to the earliest date of disease progression by the Lugano Classification (Cheson et al, 2014) as determined by BICR, commencement of new lymphoma therapy, or death from any cause.
| Percentage of participants | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo |
|---|---|---|---|---|
| 3 months | 80.00 (20.38 to 96.92) | 100.00 (100.00 to 100.00) | 100.00 (100.00 to 100.00) | 75.00 (12.79 to 96.05) |
| 6 months | 80.00 (20.38 to 96.92) | 100.00 (100.00 to 100.00) | 100.00 (100.00 to 100.00) | 75.00 (12.79 to 96.05) |
| 9 months | 80.00 (20.38 to 96.92) | 100.00 (100.00 to 100.00) | 100.00 (100.00 to 100.00) | 75.00 (12.79 to 96.05) |
Collected over Approximately 1 year and 5.5 months. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Stage 1 NKTR-255 at 1.5 µg/kg | 1/5 (20%) | 1/5 (20%) | 4/5 (80%) |
| Stage 1 NKTR-255 at 3.0 μg/kg | 0/3 (0%) | 0/3 (0%) | 3/3 (100%) |
| Stage 1 NKTR-255 at 3.0/6.0 μg/kg | 0/3 (0%) | 1/3 (33.3%) | 3/3 (100%) |
| NKTR-255 Overall | 1/11 (9.1%) | 2/11 (18.2%) | 10/11 (90.9%) |
| Placebo | 0/4 (0%) | 0/4 (0%) | 4/4 (100%) |
| Event | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Infusion related reactionInjury, poisoning and procedural complications | 0/5 | 0/3 | 1/3 | 1/11 | 0/4 |
| Upper limb fractureInjury, poisoning and procedural complications | 1/5 | 0/3 | 0/3 | 1/11 | 0/4 |
| Pneumonia aspirationInfections and infestations | 1/5 | 0/3 | 0/3 | 1/11 | 0/4 |
| Guillain-Barre syndromeNervous system disorders | 1/5 | 0/3 | 0/3 | 1/11 | 0/4 |
| Event | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | NKTR-255 Overall | Placebo |
|---|---|---|---|---|---|
| Neutrophil count decreasedInvestigations | 3/5 | 2/3 | 3/3 | 8/11 | 4/4 |
| White blood cell count decreasedInvestigations | 2/5 | 2/3 | 2/3 | 6/11 | 4/4 |
| Platelet count decreasedInvestigations | 1/5 | 1/3 | 3/3 | 5/11 | 2/4 |
| AnaemiaBlood and lymphatic system disorders | 1/5 | 1/3 | 2/3 | 4/11 | 3/4 |
| Alanine aminotransferase increasedInvestigations | 0/5 | 0/3 | 2/3 | 2/11 | 0/4 |
| VomitingGastrointestinal disorders | 0/5 | 0/3 | 2/3 | 2/11 | 0/4 |
| HypokalaemiaMetabolism and nutrition disorders | 0/5 | 0/3 | 1/3 | 1/11 | 2/4 |
| HyponatraemiaMetabolism and nutrition disorders | 2/5 | 0/3 | 0/3 | 2/11 | 1/4 |
| Aspartate aminotransferase increasedInvestigations | 0/5 | 0/3 | 1/3 | 1/11 | 0/4 |
| Blood alkaline phosphatase increasedInvestigations | 0/5 | 0/3 | 1/3 | 1/11 | 0/4 |
| Age, Continuous(years) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| Mean | 58.2 ± 16.22 | 59.7 ± 10.69 | 62.0 ± 1.00 | 63.8 ± 14.06 | 60.7 ± 11.81 |
| Age, Customized(Participants) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| Less than 65 years | 2 | 2 | 3 | 2 | 9 |
| Greater than or equal to 65 years | 3 | 1 | 0 | 2 | 6 |
| Sex: Female, Male(Participants) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| Female | 1 | 1 | 1 | 4 | 7 |
| Male | 4 | 2 | 2 | 0 | 8 |
| Ethnicity (NIH/OMB)(Participants) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| Hispanic or Latino | 1 | 0 | 1 | 0 | 2 |
| Not Hispanic or Latino | 4 | 3 | 2 | 4 | 13 |
| Unknown or Not Reported | 0 | 0 | 0 | 0 | 0 |
| Race (NIH/OMB)(Participants) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 | 0 | 0 |
| Black or African American | 0 | 1 | 1 | 0 | 2 |
| White | 4 | 2 | 1 | 4 | 11 |
| More than one race | 0 | 0 | 0 | 0 | 0 |
| Unknown or Not Reported | 1 | 0 | 1 | 0 | 2 |
| Eastern Cooperative Oncology Group (ECOG) Performance Status (PS)(Participants) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| ECOG PS 0 | 3 | 2 | 0 | 2 | 7 |
| ECOG PS 1 | 2 | 1 | 3 | 2 | 8 |
| Body Mass Index (BMI)(kg/m^2) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| Mean | 29.35 ± 5.682 | 26.01 ± 5.562 | 29.07 ± 5.022 | 26.68 ± 5.792 | 27.81 ± 5.106 |
| Baseline LDH for Randomization(U/L) | Stage 1 NKTR-255 at 1.5 µg/kg | Stage 1 NKTR-255 at 3.0 μg/kg | Stage 1 NKTR-255 at 3.0/6.0 μg/kg | Placebo | Total |
|---|---|---|---|---|---|
| Mean | 278.2 ± 229.06 | 518.7 ± 425.66 | 281.0 ± 103.81 | 301.8 ± 202.33 | 333.1 ± 245.98 |
PDFs hosted by the registry, ClinicalTrials.gov.
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Studies of the drug tested here: NKTR-255
Lymphoma, Large B-Cell, Diffuse →