A Food and Drug Administration advisory panel said Thursday that anti-anemia drugs by Amgen Inc. and Johnson & Johnson should continue to be marketed to cancer patients despite concerns the drugs could increase the risk of tumor growth and death.

The FDA’s committee of cancer-drug experts was considering whether new restrictions should be implemented to prevent most cancer patients from using the popular anemia drug Aranesp, as well as Johnson & Johnson’s Procrit.

The panel voted 13 to 1 in favor of allowing companies to continue selling the drugs for use in cancer patients undergoing chemotherapy — but the panel is still mulling whether the drugs should be restricted with certain cancer types.

Thousand Oaks-based Amgen’s anemia drug and J & J;’s Procrit both saw sales decline last year amid concern over the safety of the two drugs. Amgen lost more than $29 billion in market value last year after the medicines were tied to higher risks of stroke, heart attacks and death.

Investors showed they were confident the panel would rule in Amgen’s favor, sending shares in the biotech company up 4.7 percent to $47.10 in afternoon trading Thursday.