What happened

The stock of CTI BioPharma (CTIC) was an outlier in the biotech sector on Thursday, and in the best way possible. The company's shares surged more than 18% higher on the day, following a new and bullish analyst note on the company based on positive anecdotal evidence.

So what

That note came from Cowen prognosticator Boris Peaker, who initiated coverage on CTI stock. Peaker rates it an unequivocal outperform (read: buy), at a price target of $10 per share. Even after Thursday's price pop, that implies significant upside of more than 40% on the stock.

In March, CTI hit an important milestone when it won its first Food and Drug Administration (FDA) approval. This was for Vonjo, a treatment for a rare bone-marrow affliction called myelofibrosis. In a survey with doctors regarding the drug, Peaker found that the responses indicated "strong adoption on label," and much commercial potential for the drug.

That tracks with Vonjo's early commercial performance. In mid-May, CTI reported its first-quarter earnings, which incorporated one month of Vonjo's sales. Even in that limited window of time, the drug recorded $2.3 million in sales, so it has fine potential to be quite the revenue stream for the company.

Now what

While the new analyst note was certainly cause for optimism with CTI, some caution is merited here. Yes, sales of Vonjo were robust, but that's no guarantee the company will be able to keep up the momentum. We should also bear in mind that CTI is a biotech still deeply and consistently in the red. In that first quarter, for example, its net loss topped $37 million.