For people who wear a cumbersome mask to bed to avoid the life-threatening, long-term effects of a serious breathing disease, the prospect of shedding the headgear for a single pill taken at bedtime has been the stuff of dreams. Now, those dreams appear likely to become reality for at least some people with obstructive sleep apnea (OSA), who stop breathing dozens or hundreds of times during the night, causing their blood oxygen to drop before they subconsciously awake. Top-line results from a la...