terça-feira, junho 13, 2006
Boehringer pára estudos com tipranavir em naives
PARIS, June 13 (APM) - Boehringer Ingelheim announced on Tuesday on its website that it was closing a clinical trial of HIV drug Aptivus (tipranavir) in treatment-naïve patients due to insufficient effectiveness at 60 weeks.
Aptivus is an HIV protease inhibitor which received European marketing approval in October 2005. It is currently only indicated in combination with Abbott's Norvir (ritonavir) in treatment-experienced patients who are resistant to several protease inhibitors, on the basis of trials RESIST-1 and RESIST-2, which included about 1,400 patients.
Boehringer Ingelheim was also carrying out a trial called 1182.33 in 558 treatment-naïve patients in 15 countries including France, Germany and the UK.
This was a non-inferiority trial against Abbott's Kaletra (lopinavir/ritonavir), whose primary endpoint was the proportion of patients with an undetectable viral load (< 50 copies/mL).
Patients in both Aptivus arms received 500 mg Aptivus twice daily. Only the Norvir dose varied, at 200 mg or 100 mg twice daily.
For both doses of Norvir, Aptivus' non-inferiority was proved at 48 weeks.
Following this, the 200 mg Norvir arm was closed due to an asymptomatic elevation of liver enzyme levels. This phenomenon had already been observed in the RESIST trials.
The following analysis, carried out at 60 weeks, showed that the effect of Aptivus/Norvir (500 mg/100 mg twice daily) had declined and that this therapy was now inferior to Kaletra in terms of virologic success.
The press release does not specify the proportion of patients with undetectable viral loads, but says that there was a 15.03% difference between the Kaletra and Aptivus arms, 0.3% above the limit fixed in the trial protocol.
Boehringer Ingelheim decided at this point to halt the whole trial, specifying that this "does not change the positive benefit-risk profile of Aptivus/ritonavir (500 mg/200 mg) for the highly treatment-experienced patient population for which it is currently indicated."