French-based, clinical stage biotech company Abivax has started enrolling patients in the second Phase IIa trial, ABX464-004 study of ABX464 to treat HIV / AIDS.
ABX464 is an orally available, small molecule, therapeutic drug that is currently under clinical testing in HIV-patients.
The drug functions by inhibiting HIV replication through a new mechanism called the modulation of RNA splicing, which may not be vulnerable to the development of resistance by the HIV virus and may have a sustained effect in patients.
To be conducted at clinical centres in Spain and Belgium, the trial's first patient will be treated at University Hospital Germans Trias i Pujol in Badalona, Barcelona, Spain.
The ABX464-004 study is designed to show the long-lasting effect of ABX464, which has been observed in preclinical studies.
Around 28 patients whose HIV infection is already fully controlled by boosted Darunavir will be enrolled for the trial, preliminary results of which are expected in the last quarter of this year.
During the trial, ABX464 will be given to 21 of these patients in combination with their current drug regimen, while the remaining seven patients will be given placebo in combination with their current therapy.
After 28 days, all treatments are intended to be discontinued and the trial will then measure the time elapsed until the HIV virus reappears within the blood of the ABX464-treated patients and the control group.
The efficacy endpoint of the ABX464-004 study is the time to rebound off the viral load.
The rebound will originate from the HIV reservoirs, which are not affected by existing combination anti-retroviral treatment.
Abivax noted that an increase in the time to viral load rebound would form the first successful attempt at providing a functional cure for the HIV infection.
However, extensive clinical studies of ABX464 will be required to confirm this hypothesis.
The company expects to begin these studies by early next year.
Abivax chief medical officer Dr Jean-Marc Steens said: "Study ABX464-004 comes on the heels of the first Phase IIa study with ABX464, which demonstrated good tolerability and viral load reduction in treatment naïve patients.
"We are eager to conduct this second Phase IIa study, which we believe could demonstrate the potential of ABX464 to provide a functional cure for HIV patients."