TG Therapeutics reported phase 1 data showing its subcutaneous Briumvi formulation delivered measurable drug exposure and B-cell depletion while staying within a tolerability profile similar to the approved IV drug.
The company said the trial has now treated more than 100 patients, including more than 80 who received subcutaneous Briumvi across dose levels from 50 mg to 400 mg. More than 225 subcutaneous injections were administered, and over 75% of those were the 400 mg/2 mL dose.
On pharmacokinetics, the subcutaneous version produced a gradual absorption profile with lower peak concentrations than IV Briumvi. Mean bioavailability was greater than 60% versus IV, with the lower bound of the 95% confidence interval above 55%.
TG Therapeutics said modeling based on the phase 1 data supports both phase 3 regimens now under study. For the quarterly subcutaneous dose, the estimated geometric mean ratio for total exposure over 24 weeks was 1.21, with the lower bound of the 90% confidence interval at 1.15. For the every-other-month regimen, the estimated ratio was 1.58, with the lower bound at 1.50. In both cases, the lower bound of the 90% confidence interval was above the 0.80 threshold tied to the phase 3 non-inferiority endpoint.
On pharmacodynamics, subcutaneous Briumvi produced B-cell depletion consistent with IV Briumvi.
On safety, local injection-site reactions were reported in less than 5% of patients. Systemic injection-related reactions occurred in about 21% of patients. The company said these reactions were not dose dependent, mostly happened at the first injection, and resolved in 100% of patients. No serious injection-site reactions were seen, and no new safety signals emerged.
The phase 1 program included single* and multiple-dose cohorts across 50 mg to 400 mg, with the 400 mg dose delivered in 2 mL. TG Therapeutics said that volume is suitable for at-home self-administration via an autoinjector.
The company’s phase 3 trial is fully enrolled and testing three arms: IV Briumvi, subcutaneous Briumvi every other month, and subcutaneous Briumvi quarterly. Through week 24, the IV arm receives 600 mg total, the every-other-month arm 1,600 mg, and the quarterly arm 1,200 mg. Top-line phase 3 data are expected in late 2026 or early 2027. Following these announcements, the company's shares moved 10.47%, and are now trading at a price of $40.475. For more information, read the company's full 8-K submission here.
