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What: It's been a rough couple of months to be an investor in Sarepta Therapeutics (SRPT 6.09%). A series of positive and negative news items have caused the company's share price to behave erratically, rising and falling by double-digits multiple times this year. The end result is that shares have fallen more than 47% since the start of the year, according to data from S&P Global Market Intelligence.

SRPT Chart

SRPT data by YCharts

So what: The roller-coaster year has been triggered by a number of important developments. Here's a list of the key news items that have driven the company's share price higher or lower in 2016:

  • In January, a harsh report was released by an FDA advisory committee related to the company's Duchenne muscular dystrophy drug candidate eteplirsen. The report raised serious concerns about eteplirsen's efficacy and the methodology that was used to collect data during its clinical trials. Shares tanked.
  • Later that month, bad weather caused the FDA to postpone its scheduled advisory committee meeting to discuss eteplirsen. The meeting was rescheduled for late April, and a new PDUFA decision date of May 26th was provided.
  • In March, Sarepta's stock rocketed higher after a letter that was signed by 34 healthcare providers who specialize in DMD was posted to the University of California-Los Angeles' website. The letter urged the FDA to consider approving the drug.
  • Also in March, the company decided to consolidate its operations and announced it would be closing one of its facilities in Oregon. 
  • At the FDA's advisory committee meeting in April, news broke that the vote was seven to six against a recommended approval. Shares fell. 
  • During the company's first-quarter earnings, Sarepta reported at net loss of $52.5 million, or $1.15 per share. Sarepta's cash balance fell to $140 million.
  • In May, the FDA stated it would not meet its May 26th PDUFA date for eteplirsen, stating it needed more time and additional data before it could make a decision. Shares soared on the hopes that this hinted an approval was still a possibility.
  • Shares tanked to start June after the FDA issued final guidelines regarding the compassionate use of unapproved drugs. These new guidelines require that patients who use these drugs are only charged for the cost of manufacturing the drugs, which removes a potential source of funding for the company.
  • Just a few weeks ago, the company decided to raise $37.5 million from a secondary common stock offering.

Now what: Determining eteplirsen's chances of success is about as close to a coin flip as it gets.

On one hand, the drug was slammed by the advisory report, and the committee voted against an approval. Added to that, potential DMD treatments from both PTC Therapeutics and BioMarin Pharmaceuticals failed to win regulatory approval in the U.S. over the past year, and that makes the company's chances of success look bleak.

On the other hand, eteplirsen is the last drug standing that still offers hope to the DMD community, and it has received overwhelming support from both patients and providers. That's a fact the FDA will find hard to ignore.

The uncertainty investors now face is extremely high, which makes it hard for me to be either bullish or bearish on this company's future. I'll be staying far away from this company's stock, and I'd suggest you do the same.