looks like the interaction study was done
<a target=_blank class=ftalternatingbarlinklarge href="http://clinicaltrials.gov/ct2/show/NCT00966602
">http://clinicaltrials.gov/ct2/show/NCT00966602
</a>
From an earlier press release, it sounds like later this year
<a target=_blank class=ftalternatingbarlinklarge href="http://www.drugs.com/clinical_trials/vertex-announces-results-phase-2a-trial-vx-809-targeting-defective-protein-responsible-cystic-8824.html
">http://www.drugs.com/clinical_...ible-cystic-8824.html
</a>
"Based on the Phase 2 data announced today, Vertex plans to initiate a combination trial of VX-809 with the CFTR potentiator VX-770 in patients with the most common CFTR mutation, F508del, in the second half of 2010. In in vitro studies, a combination regimen of VX-770 and VX-809 has been shown to increase CFTR activity when compared to dosing of VX-770 or VX-809 as single agents. In addition, Vertex is conducting further analyses of the Phase 2a data and may explore the option to evaluate VX-809 doses of greater than 200 mg when dosed as a single agent".