U.S. drugmaker Regeneron Pharmaceuticals Inc missed Wall Street estimates for first-quarter profit on Thursday, due to softer sales of its blockbuster eye drug Eylea and its eczema treatment Dupixent. The company reported an adjusted profit of $9.55 per share for the quarter, compared with analysts' estimates of $10.09, according to LSEG data. Regeneron has been looking to switch Eylea patients to the high-dose version as the eye drug, which has long been its cash cow, faces the threat of biosimilars and fierce competition from rivals including Roche's Vabysmo.