You are right too. The combined effects of 770+809 on F508del will not be to the same degree as the effects of 770 on G551D. Lung function improvement, weight gain, and possible lifespan increase may not be as much. However, if the drug combo improves the quality of life for the pts with 508 mutation without long-term side effects, the trials should continue until more promising drugs are found and developed.
I agree and would love to see this combo move forward as the next generation (661) of correctors does as well, but I don't see Vertex sinking more money into the 770/809 combo given that 661 has better in vitro results and has already cleared safety hurdles and would for all intents and purposes be at the same phase of testing--assuming re-dosing is needed for 770/809. Do you think Vertex will?