Artiva's AlloNK wins FDA RMAT tag as EULAR data show 71% ACR50 in RA

Artiva Biotherapeutics has received Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA for AlloNK (AB-101) in combination with rituximab for refractory rheumatoid arthritis, the San Diego-based company announced on 8 June alongside a package of clinical data presented at the EULAR 2026 Congress in London.

The RMAT designation — reserved for regenerative medicines targeting serious conditions where early clinical evidence suggests potential over existing treatments — provides Artiva with expedited development and review benefits, including intensive early-stage dialogue with the agency. The company said the designation supports its plan to initiate a Phase 3 registrational trial in refractory RA later in 2026.

Clinical data

Across five accepted presentations at EULAR, Artiva reported results from its company-sponsored Phase 2a basket trial and an investigator-initiated basket trial in patients with long-standing, highly active RA who had failed multiple prior targeted therapies. In the company-sponsored cohort, 71% of patients with six months of follow-up achieved an ACR50 response — a threshold representing at least a 50% reduction in disease activity measures. Across a pooled RA dataset of 21 patients with at least 12 weeks of follow-up, clinical responses were first observed at three months and deepened at six months. As of the 3 April 2026 data cut, no patient had lost response, required high-dose steroids, or started a new biologic or targeted synthetic DMARD after treatment.

AlloNK is a non-genetically modified, cryopreserved allogeneic natural killer cell product designed to enhance the antibody-dependent cellular cytotoxicity of anti-CD20 monoclonal antibodies such as rituximab, thereby driving deep B-cell depletion. In translational data covering 51 evaluable autoimmune patients, uniform B-cell depletion was observed by Day 13 following a conditioning regimen of low-dose cyclophosphamide and fludarabine. Complete B-cell depletion was confirmed in all 28 RA patients assessed using a high-sensitivity assay, with subsequent reconstitution characterised by a predominance of naïve and transitional B cells, consistent with a proposed immune-reset mechanism.

Safety data from 55 autoimmune patients treated with AlloNK plus rituximab showed no cytokine release syndrome, no immune effector cell-associated neurotoxicity syndrome, and no AlloNK-related serious adverse events. The rate of Grade 3 or higher infections was 2%, and only two patients were hospitalised for treatment-emergent adverse events during the initial 28-day post-treatment period, neither event adjudicated as related to AlloNK.

Early signals were also reported in Sjögren disease and systemic sclerosis. In the SSc cohort, mean modified Rodnan skin score improved by 9.5 points among patients with six months of follow-up, and all patients achieved rCRISS25. The Sjögren dataset showed normalisation of mean stimulated salivary flow at six months, rising from 0.65 mL/min at baseline to 1.23 mL/min.

Market context

The autoimmune cell therapy space has gained momentum rapidly, largely driven by early results with CD19-directed CAR-T products in refractory lupus and RA, most notably data from academic centres in Germany using Kymriah and Yescarta off-label. Artiva is positioning AlloNK as an off-the-shelf alternative that could replicate comparable depth of B-cell depletion without the logistical burden of autologous manufacturing — a meaningful differentiator if borne out at scale, given that autologous CAR-T programmes require individualised manufacturing runs of several weeks and highly specialised infusion centres.

Several other companies are developing allogeneic NK and CAR-NK platforms for autoimmune indications, meaning Artiva will need Phase 3 data to substantiate its first-in-class ambitions in refractory RA. The RMAT pathway, alongside the company's stated cash runway extending into 2029, provides a credible near-term timeline for a pivotal readout. Investors and clinicians will be watching closely for the Phase 3 protocol design and whether the ACR50 signal holds in a larger, randomised cohort.