Cancer vaccine Phase 3 data leaked early, Moderna plunges 26%.

BlockBeats news, October 23: Phase III data for the personalized melanoma vaccine jointly developed by Moderna and Merck & Co. was leaked ahead of schedule. Despite positive clinical results, the stock still suffered a severe sell-off.

During Thursday's U.S. stock trading session, MRNA fell to as low as $180.80, down about 26.45% from the previous close and about 28.95% from the October 21 stage high of $254.48. The stock then rebounded somewhat and finally closed at $202.63, down 17.57%.

The positive results may have failed to meet continually rising market expectations.

According to Reuters, the published data showed that the combination therapy from Moderna and Merck & Co. can reduce the risk of melanoma recurrence or death by 42% and the risk of distant metastasis or death by 38%. However, after the stock had at one point risen by more than 500% cumulatively during the year, the market already had high expectations for vaccine efficacy and future commercialization prospects. Institutions such as UBS believe this decline is closer to a typical "sell the fact" move, as investors begin to reassess whether the clinical results can support the previous valuation gains.