Nkarta, Inc. filed an 8-K on November 9, 2026, disclosing initial clinical data from its Phase 1/2 Ntrust-2 basket study and integrated safety data from its Ntrust-1 and Ntrust-2 trials evaluating NKX019 in myositis and systemic sclerosis, presented at ACR Convergence 2026.

Key Highlights

  • Myositis response rate: Five of six patients (83%) at the 4 billion cells per dose level with at least three months of follow-up achieved moderate or major responses as measured by the Total Improvement Score.
  • Systemic sclerosis skin score: Median improvement in modified Rodnan skin score (mRSS) was 15 points (range, 0 to 29) at Day 90 among seven evaluable patients at the 4 billion cells per dose level.
  • rCRISS response: Six of seven evaluable systemic sclerosis patients (86%) at the 4 billion cells per dose level achieved an rCRISS-25 response or greater by Day 90.
  • Safety population: As of the September 18, 2026 data cutoff, 40 patients had been treated with NKX019 across five autoimmune indications and three dose levels, with no deaths and no treatment discontinuations due to adverse events.
  • No serious immune toxicities reported: There were no reported cases of cytokine release syndrome of any grade, immune effector cell-associated neurotoxicity syndrome, or graft-versus-host disease.
  • Protocol amendment: Based on pharmacokinetic and T-cell recovery data, the Company recently amended the Ntrust protocols to compress dosing to Days 0, 2 and 4, and plans to evaluate 6 billion cells per dose.
  • Regulatory interactions anticipated: The Company anticipates upcoming interactions with the FDA to discuss potential registrational pathways in both myositis and systemic sclerosis.

NKX019 Phase 1/2 Ntrust Data in Myositis and Systemic Sclerosis

According to the filing, Nkarta, Inc. (NASDAQ:NKTX) announced initial clinical data from its ongoing Phase 1/2 Ntrust-2 basket study evaluating NKX019, described as "an allogeneic, off-the-shelf, CD19-directed chimeric antigen receptor natural killer ('CAR NK') cell therapy candidate," in patients with idiopathic inflammatory myopathy (myositis) and systemic sclerosis. All data are as of a data cutoff of 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, for a total of 12 billion cells.

In the myositis cohort, the filing reported that among 11 patients in the baseline efficacy population across all dose levels, median disease duration was 3.5 years and nine (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 showed improvements in muscle strength as measured by Manual Muscle Testing 8, and four of eight evaluable patients (50%) achieved clinically relevant reductions in skin disease activity as measured by the Cutaneous Dermatomyositis Disease Area and Severity Index Activity Score. In systemic sclerosis, among 14 patients in the baseline efficacy population, median disease duration was 4.6 years, median baseline mRSS was 26, and five of seven evaluable patients (71%) at the 4 billion cells per dose level achieved an mRSS reduction of at least 50% from baseline by Day 90.

The filing also disclosed translational data showing deep peripheral CD19+ B-cell depletion at the 4 billion cells per dose level, with median B-cell counts remaining depleted through Day 27 (n=22). The Company stated it expects to report additional clinical follow-up in myositis and systemic sclerosis, including retreated patients, together with a plan for registrational dose selection in the first half of 2027. The filing cautioned that "the data described above are preliminary, are from a small number of patients with limited follow-up and may change as additional data become available." Statements concerning future development plans are forward-looking statements subject to the risks and uncertainties described in the filing.

What Was Disclosed

Nkarta filed an 8-K on November 9, 2026 under Items 7.01 and 8.01, furnishing a press release and webcast presentation containing initial Ntrust-2 clinical data and integrated Ntrust-1 and Ntrust-2 safety data for NKX019 in myositis and systemic sclerosis, with a data cutoff of September 18, 2026.