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



Patients will receive intravenous (IV) NKTR-255 in 21 or 28 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 with daratumumab subcutaneous (DARZALEX FASPRO TM) and rituximab or biosimilar. 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 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 DARZALEX FASPRO TM or rituximab. 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 subcutaneous (sc) interleukin-15 (IL-15) MM NHL indolent rituximab Truxima® Lymphoma Neoplasms, Plasma Cell Lymphoma, Non-Hodgkin Daratumumab 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 ≥ 500/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 3 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 3 months washout.
  • Patients who have had < 28 days since the last anti-cancer treatment, chemotherapy, biological therapy, or < 14 days from approved anti-myeloma agents, 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)

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply


  • University of California, 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