What happened

Shares of Dyne Therapeutics (DYN -2.89%) were down more than 15% for the week, as of 1 p.m. on Friday, according to data provided by S&P Global Market Intelligence. The clinical-stage biotech's stock closed at $10.98 last week, then fell to as low as $8.57 this Friday, thanks to a number of insiders selling their shares. So far this year, the stock has fallen more than 19%.

So what

Dyne focuses on treating genetic disorders. On Wednesday the company released six filings with the Securities and Exchange Commission (SEC), all showing selling by company executives on Tuesday. According to the filings, president and CEO Joshua Brumm sold 7,622 shares, chief operating officer Susanna High sold 1,635 shares, chief medical officer Wildon Farwell sold 1,707 shares, chief scientific officer Oxana Beskrovnaya sold 1,484 shares, chief business officer Jonathan McNeill sold 1,266 shares, and senior vice president Richard Scalzo sold 1,397 shares. 

It's important to note that insiders sell shares all the time for reasons that may not have anything to do with the company's future or financial health, and everything to do with personal financial situations, including tax concerns. However, the rash of insider selling was enough to worry investors.

Now what

The company has seven programs in its pipeline, but only two are in clinical trials so far: DYNE-101 and DYNE-251, both of them designed to treat myotonic dystrophy type 1 (DM1), but by attacking different targets. DM1 is a rare genetic disorder that causes muscle loss and affects 40,000 people in the United States and more than 74,000 people in Europe.

In the second quarter, the company reported no revenue and $207.7 million in cash, enough to fund operations through 2024. The company reported a net loss of $64.9 million in the quarter.