Lingering doubts about a trade deal between the U.S. and China failed to dampen investor enthusiasm or the sizzling debut of freshly-minted biopharmaceutical Cortexyme Inc..

The drugmaker that is studying potential treatments for degenerative diseases, including Alzheimer’s disease, saw its stock surge on the first day of trading — briefly doubling before paring those gains to about 70%.

In the process, the South San Francisco, California-based company saw its market value jump to $750 million in late afternoon trading.