On 9 June 2026, Japanese biotech Toregem BioPharma announced it has raised an additional US$5.3 million to begin a Phase II clinical trial of TRG-035, an experimental antibody therapy designed to regrow human teeth. The Kyoto University spin-out, co-founded by dentist-researchers including CTO Dr Katsu Takahashi, has now raised more than US$29 million in total funding. This is one of the most closely watched dental research programmes in the world, and for good reason: if it works, it would be the first drug-based alternative to dentures and implants. Here is what has actually been published, what Phase II will test, and what doctors should tell curious patients. What TRG-035 Actually Does TRG-035 is an intravenous antibody that blocks USAG-1 (uterine sensitization-associated gene-1), a protein that normally suppresses dormant tooth buds in humans. Most vertebrates regrow teeth throughout life; humans typically stop after the permanent set comes in. A landmark 2021 study in Science Advances showed that blocking USAG-1 in mice with congenital tooth agenesis allowed them to grow teeth they were genetically missing. Toregem's hypothesis is that humans retain similar dormant tooth buds, and that blocking USAG-1 could activate them. What Phase I Actually Showed The Phase I safety trial ran from late 2024 through 2025, enrolling 30 healthy adult men aged 30-64 who were each missing at least one tooth. The drug was given intravenously. As of early 2026, no serious adverse events had been reported, and data collection has wrapped, with a final report due around May 2026. This is a meaningful milestone, but it is important to be precise about what it means: Phase I trials test safety and dosing, not effectiveness. No peer-reviewed clinical data confirming actual tooth regrowth in humans has been published as of this writing. What Phase II Will Actually Test The newly announced Phase II trial will enrol patients with severe congenital hypodontia, which Toregem defines as the absence of six or more permanent teeth. Because dental implants generally cannot be placed until jaw growth is complete, children with this condition are often managed with removable dentures for years, with knock-on effects on nutrition, speech and quality of life. Phase II is designed to test whether TRG-035 can stimulate growth of these specific missing teeth in a population where both the clinical need and the ability to measure a clear outcome are highest. Will This Help Adults Who've Lost Teeth to Decay or Injury? Not yet, and not soon. Toregem has been explicit that extending this approach to adults with acquired tooth loss (from decay, gum disease or injury) is a longer-term goal, not the purpose of the current trial. The company's own stated target for general availability is around 2030, and even that timeline applies to the hypodontia indication being studied now, not a broader adult tooth-replacement product. Patients asking about this should be told plainly that it remains experimental, is not available, and is not expected to be available in the near term. Dentures and implants remain the standard of care for tooth loss today. Q&A: What Patients Are Asking Q: Is the tooth regrowth drug available now? A: No. It is in Phase II trials in Japan for a specific population with severe congenital hypodontia. There is no approved product, and none is expected before the end of the decade at the earliest. Q: Has it been proven to regrow teeth in humans? A: Not yet. Phase I (2024-2025) found the drug appears safe, with no serious adverse events in adults missing at least one tooth. No published human data yet shows new tooth growth. Phase II is designed to test that question directly. Q: What is USAG-1 and why does blocking it matter? A: USAG-1 is a protein that normally keeps dormant tooth buds inactive once a person's permanent teeth have erupted. Blocking it with TRG-035 is intended to 'wake up' these dormant buds. The concept is supported by mouse and ferret studies; human proof remains pending. Q: Could this eventually replace dental implants? A: That is the long-term ambition stated by the researchers, but it is a goal for the 2030s, not a near-term clinical option. For now, dentures and implants remain the standard of care for tooth loss. How Doctrust Connects Stories like TRG-035 generate a wave of patient questions overnight, often before a doctor has had time to read the actual trial details. When a patient asks, 'Doctor, I saw on Instagram they can regrow teeth now, can I just wait for that instead of an implant?', having an accurate, source-checked answer ready protects both the patient's treatment timeline and your credibility. Doctrust helps clinics stay ahead of viral health stories by giving doctors a structured way to log patient questions, attach evidence-based notes on emerging research, and follow up with clear guidance, all within the patient's longitudinal record. Book a free demo at www.doctrust.in to see how Doctrust keeps your patient communication accurate and your clinic ahead of the headlines.