SAN FRANCISCO, Feb. 17 The first-ever-reported Phase II data for TBR-652, which is being developed by Tobira Therapeutics for the treatment of HIV infection, demonstrate that the CCR5 receptor antagonist provides potent antiviral activity and is generally safe and well-tolerated in its proof of concept trial. The data were released here today in an oral presentation at the 17th Conference on Retroviruses and Opportunistic Infections (CROI).
In a Phase IIa trial involving 54 treatment-experienced HIV infected patients, a 10-day course of once-daily, TBR-652 monotherapy produced a median nadir decline from baseline in HIV viral load of up to 1.8 log10 copies/mL. There were no serious adverse events, deaths or study drug-related discontinuations in the study. Dose dependent changes in MCP-1 concentrations were also observed, demonstrating TBR-652's dual CCR5/CCR2 mechanism of action and potential anti-inflammatory benefits.
"These data demonstrate that TBR-652 offers potent viral suppression and excellent safety and tolerability in this short-term study," observed Calvin J. Cohen, M.D., M.Sc., of the Community Research Initiative of New England. "This compound provides the potential for once-daily dosing, without the need for a pharmacologic boosting agent, an important benefit for simplified dosing and ease of administration in early stage disease."
Dr. Cohen presented data from Study 652-2-201, a double-blind, placebo-controlled, dose-escalation trial in which patients were randomized four-to-one to receive doses of TBR-652 of 25mg, 50mg, 75mg, 100mg, 150mg and placebo.
All patients were HIV treatment-experienced, though none had previously been treated with a CCR5 antagonist. Most adverse events in the study were mild in severity (Grade 1). There were no clinically significant trends in adverse events, laboratory tests, vital signs, or electrocardiogram measurements. Additionally, there were no liver function test elevations greater than Grade 1.
The antiviral activity of TBR-652, as evidenced by reductions in HIV viral load, is outlined in the following dose-escalation chart:
Dr. Cohen noted that all patients in the 75-mg dosing group achieved a decline in HIV-1 RNA of at least 1.0 log10 copies/mL.
"Today's data presentation represents an exciting milestone for Tobira," said James Sapirstein, President and CEO of Tobira Therapeutics. "TBR-652's unique properties, including once-daily dosing that may facilitate co-formulation with other antiretrovirals, such as nucleoside-sparing or ritonavir-sparing combinations, distinguish it from the early CCR5 antagonists. Further, TBR-652's added CCR2 antagonism and potential anti-inflammatory benefits suggests a bright future for this high-potential compound."
About Tobira Therapeutics, Inc.
Tobira Therapeutics is a private biopharmaceutical company which is focused on developing and commercializing innovative antiviral compounds to treat HIV disease. The company was founded in 2006 by Eckard Weber, MD, a partner at Domain Associates, to develop novel treatments for HIV disease. Tobira has assembled a highly experienced management team with decades of clinical and commercial development experience specifically in HIV/AIDS drug development.
Median change from baseline after 10 days Median nadir change from Dosing cohort (log10 copies/mL) baseline (log10 copies/ mL) ------------- ---------------------- -------------------------- 25 mg -0.5 -0.7 ----- ---- ---- 50 mg -1.3 -1.7 ----- ---- ---- 75 mg -1.6 -1.8 ----- ---- ---- 100 mg -1.2 -1.4 ------ ---- ---- 150 mg -1.5 -1.7 ------ ---- ---- placebo +0.1 -0.2 ------- ---- ----
SOURCE Tobira Therapeutics, Inc.