Cassava Sciences, a US drugmaker, has not launched a single product in its 23 years, but that does not prevent it from becoming the fastest-growing biotech stock this year, up 925 per cent.

Behind the magical rise of the stock is optimism about an Alzheimer's drug the company is in the early stages of research, as well as a trading frenzy among retail investors.

The company is the third largest gainer in the Russell 2000 index, after PlayStation.And AMC.

"the fundamentals of our story are in place, and as far as we know, this is the first drug to restore cognition," Remi Barbier, founder and CEO of Cassava, said in an interview, referring to the Alzheimer's drug the company is developing.

The latest boost comes from an unlikely source-its competitor Biogen. This week, Biogen's new drug for Alzheimer's disease was approved by the U.S. Food and Drug Administration (FDA), driving the stock of related concepts. Cassava shares rose as much as 8.4% on Tuesday, closing up 2.03% at $68.96.

Wall Street banks that follow the stock are unanimously bullish on it. JonesTrading's Soumit Roy, who gave the stock a target price of $110, the highest among Wall Street analysts, estimates that new drugs to treat Alzheimer's could generate $200 billion in sales within 15 years. Nevertheless, Roy cautioned that Cassava, which has only one drug under development, is "not suitable for cowards"