Alpha Tau Medical (DRTS) Study result summary

Study design, technology, and mechanism of action

• Alpha DaRT uses Radium-224 embedded in titanium seeds to deliver potent, localized alpha radiation to tumors, minimizing damage to surrounding tissue due to the short range and high DNA-damaging capacity of alpha particles.

• The device leverages the decay chain of Radium-224 and its daughter isotopes, with a specialized applicator enabling precise, image-guided placement confirmed by MRI, CT, and X-ray, and no imaging artifacts.

• Preclinical studies in small and large animal models showed effective tumor cell kill, a sharp dose falloff (~4-5 mm), and minimal toxicity, supporting clinical translation.

• Combination with temozolomide or bevacizumab in glioblastoma xenografts further reduced tumor growth compared to monotherapy.

Clinical trial design and patient characteristics

• The REGAIN trial targets recurrent glioblastoma (GBM) patients previously treated with radiation, focusing on safety, feasibility, MRI response, and overall survival as endpoints.

• Eligibility includes adults 18–85 with a single enhancing lesion ≤3 cm, at least six months from initial radiation, and up to three recurrences.

• Treatment involves a one-time Alpha DaRT implantation using a radial applicator, with neurosurgical monitoring and discharge within 24–36 hours.

• The first three patients were males aged 56–71, all with WHO grade 4 IDH wild-type tumors and prior surgeries and radiation.

• FDA required interim safety analysis after the first three patients before enrolling the remaining seven.

Interim results: safety and efficacy

• All three patients had successful seed implantation with no major procedural complications or imaging artifacts; accurate source placement was confirmed by imaging.

• Interim data showed 100% local disease control and a 67% complete response rate: two patients had complete disappearance of all enhancing tumor lesions, and the third had stable disease with a 30% reduction in tumor size at one and three months.

• Adverse events included grade 2 and 3 seizures in two patients (both with prior seizure history), attributed to radiation-induced inflammation, managed with steroids and antiepileptics, with all patients returning to baseline.

• No dose-limiting toxicities, unanticipated high-grade CNS side effects, or unexpected serious adverse events were observed; patients were discharged within 24–36 hours and resumed normal activities.