Genzyme Corp. expects changes requested by the FDA after a contamination at its Allston plant to take as many as four years longer than previously projected. In May, Genzyme had anticipated repairs would take about two to three years. According to Ron Branning, Genzyme’s senior vice president of global product quality, “The change in the timeline won’t have a material impact on drug supplies.” In May, Genzyme agreed to pay a $175 million penalty after the FDA found quality issues at the Allst...