What happened

Shares of Eli Lilly (LLY -0.44%) were up 16% for the week as of 10 a.m. ET Friday, according to data provided by S&P Global Market Intelligence. The pharmaceutical company's stock closed last week at $449.49, then rose to a 52-week high of $538 a share on Tuesday. The stock is up more than 42% so far this year.

So what

The company announced second-quarter earnings on Tuesday and showed big gains in revenue, thanks mainly to diabetes therapy Mounjaro. Lilly reported quarterly revenue of $8.3 million, up 28% year over year. Mounjaro's sales were $797.7 million, up 73% over the same period last year. The drug could be approved as an obesity therapy later this year, and is already being prescribed off-label for that indication by some doctors.

Lilly also credited growth products as rising by 16% year over year to $4.93 billion, led by breast cancer therapy Verzenio, diabetes and cardiovascular therapy Jardiance, and autoimmune drug Taltz. 

The company reported net income of $1.76 billion, up 84.7% year over year, and earnings per share (EPS) of $1.95, compared to $1.05 in the same quarter a year ago.

Now what

The strong revenue growth led Lilly to upgrade guidance. It raised its yearly EPS expectations from between $9.20 and $9.40 to between $9.70 and $9.90. It also raised yearly revenue guidance by $2.2 billion to be between $33.4 billion and $33.9 billion. Some of the increase is due to the sales of the company's rights to antipsychotic therapy olanzapine and Baqsimi, a nasal spray to treat very low blood sugar. The report also led several analysts to upgrade their positions on the stock.