Nkarta, Inc. (Nasdaq: NKTX) announced initial clinical data for its investigational allogeneic CAR NK cell therapy candidate, NKX019, at the American College of Rheumatology (ACR) Convergence 2026 on November 9, 2026. The data comes from the Ntrust clinical trial program, which includes the Ntrust-1 and Ntrust-2 basket studies.

The data cutoff for the announcement was September 18, 2026. Patients at the 4 billion cells per dose level received three doses of NKX019 on Days 0, 3, and 7 following lymphodepleting preconditioning.

Myositis Results

Among 11 patients in the myositis baseline efficacy population, the median disease duration was 3.5 years, and 82% had received four or more prior therapies. At the 4 billion cells per dose level, five of six patients (83%) with at least three months of follow-up achieved a moderate or major response, as measured by the Total Improvement Score (TIS). These responses were observed across three disease subtypes: dermatomyositis, juvenile dermatomyositis, and antisynthetase syndrome. Additionally, five of six patients (83%) showed improvements in muscle strength, as measured by Manual Muscle Testing 8.

Systemic Sclerosis Results

Among 14 patients in the systemic sclerosis baseline efficacy population, the median disease duration was 4.6 years, and 64% had received at least three prior therapies. The median baseline modified Rodnan skin score (mRSS) was 26. At the 4 billion cells per dose level, seven of nine patients had reached Day 90. Of these, six (86%) achieved a revised Composite Response Index in Systemic Sclerosis (rCRISS)-25 response or greater, with five (71%) achieving an rCRISS-50 response or greater. The median improvement in mRSS was 15 points at Day 90, with five patients (71%) achieving a reduction of at least 50% from baseline.

Safety Profile

As of the data cutoff, 40 patients had been treated with NKX019 across five autoimmune indications and three dose levels. There were no deaths and no treatment discontinuations due to adverse events. 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) were reported. Adverse events were primarily hematologic, attributed to lymphodepleting preconditioning, and generally transient.

Development Plans

Based on pharmacokinetic and T-cell recovery data, Nkarta amended the Ntrust protocols to compress dosing to Days 0, 2, and 4 and plans to evaluate a 6 billion cells per dose level. The company anticipates interactions with the U.S. Food and Drug Administration regarding potential registrational pathways and expects to report additional clinical follow-up in the first half of 2027.