More than half of large employers in 2016 will aim to more tightly manage employees’ use of high-priced specialty drugs, one of the fastest-growing expenses in their health plans. Despite those efforts, companies still expect the cost of specialty drugs that are carefully administered to treat conditions such as cancer, HIV and hepatitis C to continue rising at a double-digit annual rate — well ahead of the pace for traditional pharmacy drugs or companies’ overall spending on health benefits, according to the National Business Group on Health. The group released a survey that found 55% of employers next year plan to direct employees to specialty pharmacies if they need drugs that can cost thousands of dollars for a single treatment. That share was up from a third in the group’s survey a year ago on companies’ plans for 2015 health plans.