I've just read the press release several times trying to make sure I'm understanding the figures correctly, but my interpretation is that on average, the 37 participants on Kalydeco/VX809 improved 4% from their starting FEV1 (8.5% compared to placebo, but placebo went down 4.6%, its likely at least 1/11 people in the placebo group became sick, hence the 4.6% drop). <span class="commentBody" data-jsid="text">The final Kalydeco trial with G551D had a much larger sample size, and in that trial the placebo group dropped about 1.5% over the 48 weeks, so when they say that Kalydeco had a 10.5% improvement compared to placebo, the actual improvement in the Kalydeco group from their starting point was more like 9%. I'm reading these figures off the graph so they are not 100% accurate. A 4% overall improvement is still positive, as is 35% improving by at least 5% and 19% improving by 10%. A larger sample size (37 is not that large) & a longer trial will tell us more.