Shares of the gene therapy company Voyager Therapeutics (NASDAQ: VYGR) were down by a little over 18% from their intraweek high as of 11:44 a.m. ET Friday, according to data provided by S&P Global Market Intelligence. Rather, Voyager's shares seem to be reverting to the mean following their enormous run-up earlier this month. As a refresher, the biotech's shares spiked by as much as 76% during the first two weeks of January as a result of the company's lucrative gene therapy deal with Neurocrine Biosciences (NASDAQ: NBIX).