Kalaris Expects TH103 Data In Second Half Of 2027 After Clinical Batch Misses Specification
By Elizabeth Urbanek, Executive Editor
Kalaris Therapeutics has pushed back the timeline for its lead retinal drug after a batch made for its ongoing trial failed quality testing.
According to the company's Nov. 10 third-quarter report, the pilot manufacturer producing TH103 for its Phase 1b/2 study in neovascular age-related macular degeneration (nAMD) made a batch during the third quarter that did not pass its release specification for aggregation. Kalaris said the cause was an operational issue limited to that batch. New material is expected in the second quarter of 2027.
As a result, Kalaris now expects preliminary data in the second half of 2027. In its previous quarterly update, the company had targeted the first half of the year. Any Phase 3 program would now start in 2028.
TH103 is a fusion protein delivered by injection into the eye. Patients in the study receive up to four monthly loading doses, and the trial is expected to enroll 60 to 80 people. Kalaris said enrollment and dosing are continuing.
The company also reported that it has completed the transfer of manufacturing to KBI Biopharma, which will make drug substance at commercial scale, and that KBI's first test batches met the requirements for Phase 3.
The report does not say how much TH103 is currently available for the study, whether the pace of enrollment has changed, or whether material from KBI could be used before the new pilot batch arrives.
What This Means For Clinical Supply
Small biotechs often start clinical work with one manufacturer and one batch of drug, sized to cover the study with some extra. It keeps costs down. The downside shows up in the Kalaris report: when that batch fails release, there isn't much a supply team can do except wait for the next one.
That wait is rarely short for a biologic. A replacement batch has to be manufactured, tested and released, and sometimes supported with new stability data. In this case, Kalaris doesn't expect new material until the second quarter of 2027.
The trial design adds pressure. As we see it, each patient enrolled in a loading-dose regimen commits the sponsor to several months of drug. With limited inventory, sponsors in this position usually have to decide whether to keep enrolling or hold supply back for patients already being treated. That decision should be set up in the interactive response technology (IRT) system ahead of time. Kalaris has said enrollment continues but hasn't described how it is managing inventory.
For a company with one product in development, paying for a second clinical batch up front is a hard sell. The Kalaris delay shows what’s at stake when a program depends on a single batch. A manufacturing problem at one site has now moved both its data readout and its Phase 3 plans.
The transfer to KBI settles the longer-term question of where late-stage supply will come from, but it doesn't automatically help the current study. Using material from a new manufacturer in an ongoing trial would typically require comparability data, plus changes to labeling, release and IRT.
For sponsors with a single-source biologic in early development, the operational question is how long current inventory could keep patients dosed if the next batch failed release.
The Supply Question
Is a second clinical batch worth the money for a single-asset biologic program, or is a delayed readout the price of running lean?
Related Clinical Supply Leader Editorials:
- The Phase 2 Manufacturing Wall: The CMC Risk Hiding In Plain Sight
- What Your Tier 1 Supplier Map Might Be Missing
- What Happens When The Clinical Forecast Changes?
About The Editor:
Elizabeth Urbanek is the Executive Editor for Clinical Supply Leader, where she works with clinical trial supply and logistics professionals across pharma and biotech to bring real-world perspectives, operational challenges, trends, scientific insights and regulatory strategy to the field.
Before joining life sciences media, Elizabeth spent more than 15 years in broadcast, digital and live-event storytelling, helping highly technical teams communicate complex ideas with clarity and impact. She brings that same approach to clinical supply, creating editorial space for experts to share what is happening across clinical trial operations.
Elizabeth is passionate about connecting people and ideas, identifying emerging themes and showcasing work that can move the clinical supply field forward.