Kalaris Therapeutics (KLRS) is having a good Friday. The clinical-stage biopharmaceutical company released expanded data from its Phase 1a trial of TH103, a treatment for neovascular age-related macular degeneration (AMD), and the stock jumped nearly 18%.

The updated results build on earlier findings, showing improvements in vision and retinal anatomy. The study included 17 treatment-naive patients and three who had been treated before, all tracked for six months.

Extended Durability: The Key Takeaway

The big story here is how long TH103 might keep patients from needing another injection. After just one dose, 41% of treatment-naive patients went four months or longer before needing a retreatment. Even better, 35% made it to five months, and 29% went the full six months without any additional anti-VEGF therapy. For patients who had already been treated, the average interval between retreatments extended by two months compared to their prior therapies.

That kind of durability could be a game-changer. Current anti-VEGF drugs often require monthly or bimonthly injections, which is a burden for patients. TH103 seems to stick around longer. The data on plasma pharmacokinetics showed strong intraocular retention, with maximum plasma concentrations 27- to 53-fold lower than existing leading anti-VEGF products on a molar equivalence basis. That supports the company's hypothesis that the drug's prolonged biological activity can stretch out the time between treatments.

Safety and What's Next

Safety is always the other side of the coin. In the six patients who received the 2.5 mg dose—manufactured with updated processes to minimize impurities—there were no cases of intraocular inflammation. Previously, one patient at the 5 mg dose had temporary inflammation, but it resolved without complications.

Kalaris is already enrolling patients in a Phase 1b/2 study with an ascending-dose design to evaluate a standard four-dose loading course. The results will help determine the dose for potential Phase 3 trials, with initial data expected in the first half of 2027.

As of Friday's publication, Kalaris shares were up 17.79% at $5.43. Not bad for a day's work.