As a general rule run flats generate more noise and have a harsher ride compared to a conventional summer tyre of the same size, as the sidewalls are stiffer in order to provide the run flat facility. Other than adding more sound deadening there is little you can do about the road noise. You could change the tyres for either a run flat with a lower noise rating, or switch to a conventional non-run flat tyre. A conventional tyre will likely provide a better ride and reduced noise, although fitting winter tyres would also improve the ride the noise levels will likely be higher than a summer tyre. The only downside to bear in mind is that by fitting conventional tyres you will need to find a suitable contingency in the event of a puncture, such as a space saver spare wheel, jack and wheelbrace, or an emergency tyre inflation kit.