Kalaris Therapeutics Shares Jump 29% on Positive Phase 1a Trial Data

Kalaris Therapeutics Inc. (NASDAQ:KLRS) saw its shares increase by 29% on Friday following the release of positive results from its Phase 1a single ascending‑dose trial of TH103 in patients with neovascular age‑related macular degeneration (AMD).

The trial was expanded to include a safety cohort of 20 patients, comprising 17 treatment‑naive individuals and 3 treatment‑experienced individuals, all of whom completed six months of follow‑up. The expanded dataset confirmed improvements in both visual acuity and retinal anatomy, building on earlier findings.

Pharmacokinetic analysis demonstrated that TH103 achieved a 27‑ to 53‑fold lower maximum plasma concentration (Cmax) compared with currently approved anti‑VEGF agents on a molar‑equivalence basis, indicating substantially greater intraocular retention of the drug.

Retreatment timing after a single TH103 injection was notably delayed: 41% of treatment‑naive patients required their first retreatment at four months or later, 35% at five months or later, and 29% did not receive any additional anti‑VEGF therapy throughout the six‑month observation period. In the treatment‑experienced subgroup, the interval to retreatment was extended by an average of two months relative to their prior anti‑VEGF treatment schedules.

Safety outcomes showed no cases of intraocular inflammation among the six patients who received the 2.5 mg dose, which was manufactured after process adjustments aimed at reducing impurities. One patient administered the 5 mg dose experienced a transient episode of intraocular inflammation that resolved without lasting effects.

Kalaris is currently enrolling participants in a Phase 1b/2 study that will evaluate a standard four‑dose loading regimen of TH103 in treatment‑naive patients. This study will assess safety, tolerability, pharmacokinetics, preliminary efficacy, and time to retreatment after completion of the loading course. The company expects to release initial data from the Phase 1b/2 trial in the first half of 2027.