What happened

Shares of the clinical-stage biotech Cassava Sciences (SAVA 0.20%) rose by as much as 15% in pre-market trading Tuesday morning. The small-cap company's shares are perking up today in response to a fairly sizable insider buy by board member Sanford Robertson.

Last Friday, Robertson reportedly purchased 36,281 shares at an average price of $8.92 per share, according to a Form 4 filed with the Securities and Exchange Commission. Per the filing, this particular board member now owns a whopping 912,623 shares after this latest acquisition. 

A medical report labeled Alzheimer's disease.

Image source: Getty Images.

So what

Cassava's shares have already jumped by a staggering 250% over just the past two weeks, thanks to the strong mid-stage trial results for its experimental Alzheimer's disease (AD) medication known as sumifilam. The big deal is that there are no AD drugs on the market that are truly disease-modifying.

So the first drug to halt the course of the disease, slow it down, or perhaps reverse it, would have a real shot at becoming the best-selling pharma product of all time. While sumifilam is a long shot to fill this unmet medical need, this recent insider buy implies that at least one board member has a fair amount of confidence in the drug's future.  

Now what

What's the next logical step? Cassava doesn't have the financial resources necessary to advance sumifilam into a costly phase 3 trial. So the company will more than likely partner with a larger pharma, or perhaps attempt to sell itself outright. This red-hot biotech's recent run, in turn, may be far from over. Stay tuned.