GSK has reported positive data from a Phase IIa clinical trial of investigational antitubercular agent, GSK3036656, to treat patients with drug-susceptible pulmonary tuberculosis.

Named Study 201214, the single-centre, open-label trial analysed the safety, early bactericidal activity (EBA), and tolerability of GSK3036656 in these patients.

Trial subjects were randomised into a 3:1 ratio to receive either a 1mg, 5mg, 15mg, or 30mg dose of GSK3036656, or a standard-of-care (SoC) regimen for drug-sensitive TB.

The rate of variation in log10colony forming units (CFU) per mL of direct respiratory sputum samples over the period baseline to day 14 (EBA CFU0-14) was the trial’s primary endpoint.

The rate of variation in time to sputum culture positivity (EBA TTP) over the time period baseline to day 14 (EBA TTP0-14) was the key secondary outcome of the trial.

According to trial data, GSK3036656 was found to be well tolerated and demonstrated EBA with a low, once-a-day oral dose of GSK3036656.

No serious adverse events (SAEs) linked to the treatment were reported in the trial.

In all the subjects who received 30mg of GSK3036656, PET CT imaging of the lungs showed a decline in TB disease over 14 days.

GSK3036656 hinders the leucyl t-RNA synthetase (LeuRS) enzyme to suppress protein synthesis in Mycobacterium tuberculosis (Mtb).

The company plans to now assess varying regimens of the agent in Phase IIb/c trials to identify the suitable partner agents that support its anti-TB action and the best treatment durations.

GSK Global Health Medicines R&D head David Barros-Aguirre said: “Existing treatments for TB can be complicated, of long duration, and have serious side effects, which significantly impact the lives of patients with TB around the world.

“The encouraging data provide a good foundation from which to investigate GSK3036656 in different combinations in Phase IIb/c studies, with the aim of contributing to shorter, simpler, and better tolerated treatment regimens for patients with TB.”

In October this year, the company reported positive interim data from the ZOSTER-049 extension study of its recombinant, adjuvanted Zoster vaccine Shingrix against shingles.