Nkarta Reports Initial NKX019 Clinical Responses in Myositis and Systemic Sclerosis Trials

Nkarta (NASDAQ:NKTX) has reported preliminary clinical data from its Ntrust trial programme evaluating NKX019, an investigational allogeneic CAR natural killer (NK) cell therapy, in patients with autoimmune diseases.

The findings, presented at the American College of Rheumatology Convergence 2026 meeting in Orlando, included early treatment responses in patients with myositis and systemic sclerosis.

The data cutoff was September 18, 2026, with results based on a limited number of patients and relatively short follow-up periods.

Ntrust-2 Study Reports Responses in Myositis and Systemic Sclerosis

In the Ntrust-2 study, five of six myositis patients (83%) receiving 4 billion NKX019 cells per dose achieved moderate or major responses according to the Total Improvement Score. All six patients had completed at least three months of follow-up.

Among systemic sclerosis patients treated at the same dose level, six of seven (86%) achieved an rCRISS-25 response or greater by Day 90, while five of seven (71%) reached an rCRISS-50 response or greater.

The study also assessed changes in skin involvement among systemic sclerosis patients.

At Day 90, patients receiving the 4 billion-cell dose demonstrated a median 15-point reduction in the modified Rodnan skin score, a measure of skin thickness.

Five of seven patients (71%) achieved a reduction of at least 50% from baseline.

Safety Data Cover 40 Patients Across Five Autoimmune Indications

Nkarta reported safety findings from 40 patients treated with NKX019 across five autoimmune disease indications and multiple dose levels.

No cases of cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, hemophagocytic lymphohistiocytosis-like syndrome or graft-versus-host disease were reported.

The company also reported no deaths or treatment discontinuations due to adverse events.

Infusion-related reactions occurred in five patients, representing 12.5% of those treated. Most were Grade 1, and all resolved within 24 to 48 hours.

Other adverse events were predominantly hematologic and were attributed to the lymphodepleting treatment administered before NKX019 infusion.

Nkarta Revises Dosing Schedule and Plans Higher-Dose Evaluation

Following the initial findings, Nkarta amended its Ntrust study protocols to shorten the dosing schedule, with NKX019 administration planned for Days 0, 2 and 4.

The company also intends to evaluate a higher dose of 6 billion cells per administration, compared with the 4 billion-cell dose used in the reported efficacy cohorts.

Nkarta expects to engage with the US Food and Drug Administration to discuss potential registration pathways for NKX019 in myositis and systemic sclerosis.

Additional clinical data and a plan for selecting a dose for registrational studies are expected during the first half of 2027.

Further Clinical Data Expected in 2027

NKX019 remains an investigational therapy, and the reported findings are preliminary.

The company acknowledged that the results are based on small patient populations and limited follow-up, restricting conclusions about long-term effectiveness and safety.

The next stages of the programme will include evaluation of the revised dosing schedule, assessment of the higher dose and continued monitoring of clinical responses.

Nkarta expects to provide further clinical results and details of its proposed registrational development strategy in the first half of 2027.

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