But the drug "hits a lot of targets, and one concern is to make sure you are not inducing an untowardeffect in people who are not as severe as kids with progeria, " Dr. Collins said.
The fact that such exceptions must be authorized on a case-by-case basis, however, offers some basis for ensuring that they are made deliberately and on the basis of merit -- and do not have the untowardeffect of undermining the sanctions in place.