With a 100% response rate in a Phase II study, KYV-101 sets a new efficacy bar in generalized myasthenia gravis, according to analysts at William Blair.
Kyverna Therapeutics on Wednesday touted a 100% response rate in patients with generalized myasthenia gravis who were treated with the investigational CAR T cell therapy KYV-101, beefing up the asset’s profile as it enters late-stage development.
Analysts at William Blair wrote to investors that this magnitude of efficacy establishes “a new efficacy standard in the field,” making KYV-101 “differentiated from current therapies and other late-stage assets.” Wednesday’s data also “significantly” de-risks the planned Phase III trial, according to the analysts.
Wednesday’s data come from the mid-stage portion of the Phase II/III KYSA-6 study, a single-arm, open-label and registrational trial testing the impact of KYV-101 on disease-related activities of daily living. At the time of readout, six patients with moderate to severe generalized myasthenia gravis (gMG) were evaluable, all of whom had previously failed immunosuppressant therapies.
At 36 weeks, all six patients achieved “clinically meaningful” improvements in activities of daily living versus baseline, according to Kyverna. All treated patients also met the criteria for treatment response, which Kyverna defined as demonstrating at least a 3-point reduction in two disease inventories.
Mid-stage data likewise suggest that KYV-101 could help lower treatment burden, with all treated patients being able to stop non-steroidal immunosuppressants, high-dose steroids and other therapies after 24 weeks. As for safety, Kyverna found KYV-101 to be well-tolerated, with no documented cases of high-grade cytokine release syndrome or immune effector cell–associated neurotoxicity syndrome.
One patient developed grade 4—or life-threatening—neutropenia, though this complication was “expected,” according to Kyverna, and the patient had improved to grade 1 by the time of the data cutoff.
Kyverna will now move on to the Phase III portion of KYSA-6, for which it expects to start enrollment by the end of this year, Chief Medical and Development Officer Naji Gehchan said in a statement on Wednesday.
With these latest data, Kyverna joins Cabaletta Bio in pushing CAR T therapies, which have so far been established in cancer, into the autoimmune space. Earlier this week, Cabaletta reported promising signals of efficacy for its cell therapy rese-cel in dermatomyositis, systemic lupus erythematosus, systemic sclerosis and antisynthetase syndrome. Cabaletta Is planning to take rese-cel into a registrational study for myositis and is looking to align with the FDA on trial designs for lupus and systemic sclerosis this year.
Other companies leveraging the CAR T platform for autoimmune diseases include Bristol Myers Squibb, CRISPR Therapeutics and Autolus Therapeutics.
