• No cases of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), or graft-versus-host disease (GvHD) across 40 patients treated across five indications in the Ntrust program.
  • No deaths and no treatment discontinuations due to adverse events.
  • Grade 3 or higher treatment-emergent adverse events were primarily hematologic and attributed to lymphodepletion.
  • Five patients (12.5%) had infusion-related reactions deemed associated with NKX019; all resolved within 24-48 hours and without tocilizumab.
  • No increase in adverse events was observed at higher doses.

SOUTH SAN FRANCISCO, Calif., Nov. 11, 2026 (GLOBE NEWSWIRE) — Nkarta, Inc. (Nasdaq: NKTX), a clinical-stage biotechnology company developing engineered natural killer (NK) cell therapies to treat autoimmune diseases, today announced integrated safety results from 40 patients treated with NKX019, an allogeneic, off-the-shelf, CD19-directed CAR NK cell therapy candidate in its ongoing Ntrust clinical trial program.

The findings were presented today in an oral presentation at the American College of Rheumatology (ACR) Convergence 2026 in Orlando by Guillermo J. Valenzuela, M.D., of Integral Rheumatology and Immunology Specialists in Plantation, Florida. The data cutoff was September 18, 2026. The cumulative safety analysis included patients with systemic sclerosis, myositis, lupus nephritis, rheumatoid arthritis, and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis.

There were no deaths and no treatment discontinuations due to adverse events. There were no reported cases of CRS of any grade, ICANS, IEC-HS or GvHD. No cases of leukoencephalopathy, a neurotoxicity associated with fludarabine, have been reported to date.

“The absence of CRS, ICANS, IEC-HS and GvHD across 40 patients and five autoimmune diseases reinforces our belief that CAR NK cells could offer a differentiated approach to autoimmune cell therapy,” said Paul J. Hastings, Chief Executive Officer of Nkarta. “Unlike CAR T cells, which can undergo rapid and substantial expansion in the body, NKX019 is designed to deliver targeted B-cell depletion with limited in vivo expansion and more predictable cellular exposure. These fundamental biological differences may allow us to achieve the therapeutic benefits of CD19-directed cell therapy without the toxicities associated with autologous T cell-based modalities.”

Integrated Safety Results 

The integrated analysis included 40 patients enrolled in the Ntrust Phase 1/2 clinical trials. Patients had active or progressive disease despite previous use of standard-of-care therapies, with 30 patients (75%) receiving four or more prior treatments. Median disease duration was 4.7 years (range 0.3 to 30.7).

Patients received outpatient lymphodepleting preconditioning with fludarabine and cyclophosphamide, followed by a three-dose cycle of NKX019 at 1 billion, 2 billion or 4 billion cells per dose. Twenty-eight patients (70%) received the 4 billion cell dose, seven (17.5%) the 2 billion cell dose and five (12.5%) the 1 billion cell dose. Treatment-emergent adverse events were defined as adverse events occurring from the start of lymphodepletion through 30 days after the last NKX019 dose, regardless of causality.

Key findings from the integrated safety analysis included:

  • No immune effector cell-associated toxicities or GvHD: No cases of CRS, ICANS, IEC-HS or GvHD were reported across all 40 patients and five disease indications.
  • No deaths or treatment discontinuations: No deaths and no treatment-emergent adverse events leading to treatment discontinuation were reported.
  • Grade 3 or higher adverse events predominantly hematologic: Treatment-emergent adverse events occurred in 34 patients (85%), including grade 3 or higher events in 14 (35%), most commonly hematologic and typically attributed to lymphodepletion. Hematologic changes generally recovered within one to two months; grade 3 or higher cytopenias lasting more than 28 days in five patients (12.5%).
  • Infusion-related reactions: Five patients (12.5%) had infusion-related reactions associated with NKX019: four were grade 1 and one was grade 3. All resolved within 24 to 48 hours with standard supportive care, without the use of tocilizumab.
  • Consistent tolerability across dosing cohorts: No increase in adverse event frequency was observed across the 1 billion (n=5), 2 billion (n=7) or 4 billion cell (n=28) dose levels.

NKX019 is manufactured from healthy donor-derived NK cells and cryopreserved for delivery to clinical sites. It does not require patient leukapheresis or individualized manufacturing.

“For patients living with refractory autoimmune diseases, the burden is progressive disability, pain and the uncertainty of whether the next treatment will work after so many others have failed,” said Dr. Valenzuela. “Cell therapy offers new hope, but access is currently constrained by where patients live and whether they can access a highly specialized treatment center. If we can deliver the therapeutic potential of CD19-directed cell therapy with a manageable safety profile, patients could receive these treatments in their own communities from rheumatologists who know them. That would represent a sea change in autoimmune care.”

About the Ntrust℠ Clinical Trials in Autoimmune Disease
Ntrust-1 (NCT06557265) and Ntrust-2 (NCT06733935) are multi-center, open-label, dose-escalation clinical trials in patients with autoimmune disease receiving lymphodepletion followed by CD19-targeted CAR NK cell therapy. Both trials assess the safety of NKX019 in people living with autoimmune diseases as well as its potential to achieve durable remission via a “reset” of the immune system through the elimination of pathogenic B cells.

The Ntrust trials are enrolling up to 12 patients per dose level per disease indication. Additional patients may be enrolled if needed to refine patient populations for further study.

In both studies, patients receive a three-dose cycle of NKX019 following lymphodepleting preconditioning with fludarabine and cyclophosphamide or cyclophosphamide alone, if they have significant cytopenia at baseline. This approach is designed to evaluate the single-agent activity of NKX019 and facilitate a more rapid path to regulatory approval. Patients in both trials may also receive additional cycles, if needed, to restore response or enable a deeper response.

About NKX019
NKX019 is an allogeneic, cryopreserved, off-the-shelf immunotherapy candidate that uses natural killer (NK) cells derived from the peripheral blood of healthy adult donors. It is engineered with a humanized CD19-directed chimeric antigen receptor (CAR) for enhanced cell targeting and a proprietary, membrane-bound form of interleukin-15 (IL-15) for greater persistence and activity without exogenous cytokine support. CD19 is a biomarker for normal B cells as well as those implicated in autoimmune disease. Nkarta is evaluating NKX019 in multiple autoimmune conditions.

About Nkarta
Nkarta is a clinical-stage biotechnology company advancing the development of allogeneic, off-the-shelf natural killer (NK) cell therapies for people living with autoimmune diseases. By harnessing the power of the innate immune system to eliminate pathogenic B cells driving the autoimmune response, Nkarta is advancing novel cell therapies engineered for deep therapeutic impact. The on-demand availability and outpatient dosing of our CAR NK cells enable a broad population of patients with different autoimmune conditions to conveniently access NK cell therapy in community health settings. For more information, please visit the company’s website at www.nkartatx.com.

Cautionary Note on Forward-Looking Statements
Statements contained in this press release regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. Words such as “anticipates,” “believes,” “expects,” “intends,” “plans,” “potential,” “projects,” “would” and “future” or similar expressions are intended to identify forward-looking statements. Examples of these forward-looking statements include, but are not limited to, statements concerning Nkarta’s expectations regarding any or all of the following: Nkarta’s position, plans, strategies and timelines for the continued and future clinical development and potential of NKX019 (including the future availability and disclosure of clinical data and other updates from Nkarta’s clinical trials); the potential differentiation of NKX019 and CAR NK cell therapy from other cell therapy modalities; and the therapeutic potential, accessibility and tolerability of NKX019 for the treatment of autoimmune diseases, including as a result of advancing Nkarta’s dose escalation and expansion of outpatient dosing in community-based settings.

Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. These risks and uncertainties include, among others: Nkarta’s limited operating history and historical losses; Nkarta’s lack of any products approved for sale and its ability to achieve profitability; the risk that the results of preclinical studies and early-stage clinical trials may not be predictive of future results; the risk that initial, interim or preliminary data from Nkarta’s clinical trials, including the data presented at ACR Convergence 2026, reflect a limited number of patients with limited follow-up, may change as more patient data become available and may not be predictive of future results; Nkarta’s ability to raise additional funding to complete the development and any commercialization of its product candidates; Nkarta’s dependence on the clinical success of NKX019, including in its lead indications of myositis and systemic sclerosis; risks associated with outpatient administration of NKX019 at community-based sites; that Nkarta may be delayed in initiating, enrolling patients in or completing its clinical trials; competition from third parties that are developing products for similar uses; Nkarta’s ability to obtain, maintain and protect its intellectual property; Nkarta’s dependence on third parties in connection with manufacturing, clinical trials and preclinical studies; and the complexity of the manufacturing process for CAR NK cell therapies.

The data described in this press release are preliminary, are from a small number of patients with limited follow-up and may change as additional data become available. No head-to-head studies have been conducted comparing NKX019 with other therapies, and caution should be exercised in drawing conclusions from comparisons of data across separate trials, which may differ in design, patient populations and other factors.

These and other risks and uncertainties are described more fully in Nkarta’s filings with the Securities and Exchange Commission (“SEC”), including the “Risk Factors” section of Nkarta’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2026, filed with the SEC on November 5, 2026, and Nkarta’s other documents subsequently filed with or furnished to the SEC. All forward-looking statements contained in this press release speak only as of the date on which they were made. Except to the extent required by law, Nkarta undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.

Nkarta Media/Investor Contact:
Nadir Mahmood
Nkarta, Inc.
nmahmood@nkartatx.com


Primary Logo

Media gallery

About The Author
Nkarta, Inc.