Image source: Stockmonkeys.com via Flickr.

What: After investment research firm Jefferies upgraded the stock to a "buy," shares of Karyopharm Therapeutics Inc. (KPTI -3.54%) have skyrocketed 31.6% at 1:00 p.m. EDT Tuesday.

So What: Karyopharm Therapeutics is a clinical-stage company developing therapies for the treatment of hematological cancers, including multiple myeloma.

The company's most advanced drug is selinexor, which is being evaluated in multiple myeloma, acute myeloid leukemia, diffuse aggressive lymphoma, and other malignancies. Results from its phase 2b clinical trial evaluating selinexor plus low-dose dexamethasone in heavily pretreated multiple myeloma patients is expected later this quarter.

Ahead of that data, Jefferies has boosted its rating on the stock from a "hold" to "buy." Jefferies analysts also set a price target of $12 for Karyopharm Therapeutics shares.

Now What: There's a significant need for new treatment options for heavily pretreated cancer patients, and in previous studies selinexor has shown solid efficacy. In June, a study conducted at the Moffitt Cancer Center showed that six of 10 patients had some level of response to a treatment regimen containing selinexor.

Karyopharm Therapeutics reported in June that 43% of heavily pretreated patients with diffuse large B-cell lymphoma who took selinexor for at least one month showed an overall response rate, too.

If the company's upcoming data is positive, then management plans to approach the FDA to discuss an accelerated approval. Such an approval would be welcome news for investors because the company's cancer operating expenses are clocking in at an annualized $120 million pace.

The multiple myeloma market is worth billions of dollars in sales annually, so an eventual approval could significantly improve the company's financials. It could also spark interest from potential acquirers, and for those reasons Karyopharma Therapeutics is an intriguing, yet high-risk stock.