for people ages 18-80 (full criteria)
study started
estimated completion



Patients will receive intravenous NKTR-255 in 21-day treatment cycles. During the Part 1 dose escalation portion of the trial, NKTR-255 will be given as monotherapy. After determination of the recommended Phase 2 dose (RP2D) of NKTR-255, NKTR-255 will be evaluated in 3 expansion Cohorts in Part 2. Cohort A will enroll Non-Hodgkin Lymphoma (NHL) patients that have relapsed after CAR-T therapy. Cohort B will enroll patients with relapsed/refractory Multiple Myeloma (MM). Cohort C will enroll patients with relapsed/refractory indolent Non-Hodgkin Lymphoma (iNHL). This is a Phase 1 study to evaluate safety and tolerability of NKTR-255 alone and in combination with daratumumab or rituximab.

Official Title

A Phase 1, Open-label, Multi-center, Dose Escalation and Dose Expansion Study of NKTR-255 as a Single Agent in Relapsed or Refractory Hematological Malignancies


NKTR-255 is a cytokine that is designed to regulate T and natural killer cell activation, proliferation and promote their anti-tumor effects.

This is a Phase 1, open-label, multi-center, dose escalation, dose expansion, safety follow-up, and survival follow-up of NKTR-255 as a single agent and NKTR-255 in combination with daratumumab or ritixumab. Study treatment is defined as any investigational treatment(s) or marketed product(s), intended to be administered to a study patient according to the study enrollment.

Part 1 will enroll relapsed/refractory MM and NHL patients. In Part 2, Cohort A will enroll NHL patients who have progressed on a chimeric antigen receptor T-cell (CAR-T) product, Cohort B will enroll MM patients who previously received daratumumab and other anti-CD38 therapies to receive NKTR-255 alone and/or in combination with daratumumab, and Cohort C will enroll iNHL patients who previously received rituximab and other therapies to receive NKTR-255 alone and/or in combination with rituximab.


Multiple Myeloma Non-Hodgkin Lymphoma Indolent Non-Hodgkin Lymphoma relapsed refractory NKTR-255 CAR-T daratumumab interleukin-15 (IL-15) MM NHL indolent rituximab Lymphoma Neoplasms, Plasma Cell Lymphoma, Non-Hodgkin Dose Escalation of NKTR-255 Dose Expansion of NKTR-255 alone


You can join if…

Open to people ages 18-80

  • Patients must have relapsed or refractory MM or NHL with no available therapies that would confer clinical benefit for their primary disease.
  • Measurable or detectable disease according to International Myeloma Working Group (IMWG) and the Lugano Classification. Extranodal NHL disease that is measurable by fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging only is allowed.
  • Estimated glomerular filtration rate (eGFR) ≥ 40 mL/min/1.73 m2.

Patient has the following laboratory test results during Screening:

  1. Absolute neutrophil count (ANC) or absolute granulocyte count (AGC) ≥ 1000/µL
  2. Platelets ≥ 30,000/µL
  3. Hemoglobin ≥ 8g/dL
  4. Absolute lymphocytes ≥ 700/µL
  5. Leukocytes ≥ 3000/µL

Patients are eligible who also meet all the following criteria in these cohorts of Part 2:

Cohort A only:

• Patients with NHL who received a commercially approved CD19 CAR-T product and had PD. The first dose of NKTR-255 will be administered within 30 days of the PD.

Cohort B only:

  • Patients with MM must have had previous exposure to proteasome inhibitor, immunomodulatory agent (IMiD), and anti-CD38 therapy.
  • Patients who previously received daratumumab or other anti-CD38 therapies must have at least 6 months washout.

Cohort C only:

• Patients with relapsed or refractory iNHL who previously progressed during or following 1 or more prior systemic rituximab-containing (or another treatment with an anti-CD20 antibody-containing) regimens for lymphoma.

You CAN'T join if...

  • Patients who have an active, known, or suspected autoimmune disease.
  • Any treatment-related neurotoxicity or cytokine release syndrome (CRS) prior to enrollment into the study should return to baseline before NKTR-255 treatment.
  • Active central nervous system (CNS) involvement with NHL.
  • Patients who have been previously treated with prior interleukin-2 or interleukin-15.
  • Patients who received daratumumab or other anti-CD38 therapies previously must have 6 months washout.
  • Patients who have had < 28 days since the last anti-cancer treatment, chemotherapy, biological therapy, or < 14 days from approved tyrosine kinase inhibitor therapy (sunitinib, sorafenib, vemurafenib, dabrafenib, cobimetinib), or systemic or inhaled steroid therapy at doses greater than 10 mg of prednisone or equivalent before administration of the first dose of study drug(s).
  • Prolonged Fridericia's corrected QT interval (QTcF) > 450 ms for men and > 470 ms for women at Screening.
  • Contraindication to or unable to receive daratumumab (Cohort B only)


  • University of California at San Francisco accepting new patients
    San Francisco California 94143 United States
  • City of Hope accepting new patients
    Duarte California 91010 United States


accepting new patients
Start Date
Completion Date
Nektar Therapeutics
Phase 1
Study Type
Last Updated