What happened

Shares of Puma Biotechnology (PBYI -3.44%) were up as much as 13% this week. As of Thursday afternoon, they were still up more than 10% for the week, according to data from S&P Global Intelligence.

The biotech company, which focuses on cancer therapies, closed at $4.40 a share last Friday. It opened on Monday at $4.35 and then got as high as $5.16 on Wednesday. The stock has a 52-week low of $1.60 and a 52-week high of $5.16.

So what

On Tuesday, the company disclosed in a filing that Puma CEO Allan Auerbach bought 568,181 shares of Puma stock for roughly $2.5 million dollars and now owns 20% of the company. The choice was seen as a sign Auerbach has faith in the company's pipeline beyond its only marketed product, Nerlynx, used to treat HER2-positive breast cancer, a type of breast cancer that utilizes a protein called human epidermal growth factor receptor 2 (HER2). It is seen in one of every five breast cancer cases. The drug is also being examined to treat HER2-positive cervical cancer as well as non-small-cell lung cancer.

The company's other drug candidate is Alisertib, an Aurora kinase A inhibitor that is being tested as a combination therapy against various types of breast cancer and small-cell lung cancer. 

Now what

The company is close to becoming profitable. In the third quarter, it reported revenue of $54.3 million, up 25%, year over year, and earnings-per-share (EPS) loss of $0.01 compared to an EPS loss of $0.04 in the same period a year ago. Investors are waiting to see how many label expansions the company can achieve with Nerlynx and how Alisertib fares in later trials.