The Food and Drug Administration said a shortage of the leukemia drug cytarabine has been resolved, although record shortages remain for cancer drugs and medicine used by hospitals for critical care.

Cytarabine has been in short supply for about a year, but the shortage became so severe in the spring that even top cancer centers were unable to get it at times.

Cytarabine is the main treatment for people with acute myeloid leukemia, or AML, and part of a treatment regimen for other types of blood cancers. For AML patients, there was no substitute drug.

Valerie Jensen, the associate director of FDA's drug shortage program, said production problems at Hospira Inc. (HSP) and APP Pharmaceuticals, a unit of Fresenius SE (FRE.XE), have been fully resolved, and that there's currently "really good national supply" of cytarabine.

In 2010, Hospira had problems getting active ingredient used to make cytarabine. Then Hospira and APP Pharmaceuticals had problems with particles in some of the cytarabine vials, which temporarily stopped shipments of the medicine. The particles turned out to be tiny clumps of dried active ingredient.

As a stop-gap measure, the FDA allowed the cytarabine to be shipped with instructions that the vials be warmed to dissolve the clumps before the drug was administered.

A third manufacturer of cytarabine, Bedford Laboratories, couldn't keep up with demand while the other firms resolved their manufacturing problems.

Although the cytarabine shortage is resolved the FDA, companies and hospitals are still grappling with shortages of other drugs, including Johnson & Johnson's (JNJ) cancer drug Doxil.

The Food and Drug Administration reported a record 178 drug shortages in 2010 and has said there's a greater number of shortages so far this year.

Most of the shortages involve older, generic drugs administered by injection or intravenously. Along with cancer drugs, they also include antibiotics to treat infections and nutritional drugs for patients who can't eat.

Most of the drugs are generic, not highly profitable and are now made by only one or two companies. Teva Pharmaceutical Industries Ltd. (TEVA) and Hospira are two of the bigger producers of generic drugs.

The shortages are growing more severe, in part because of industry consolidation and manufacturing problems in the past year. When one company runs into a manufacturing problem with a product or decides to quit making a drug, competing companies can't quickly fill the void. In April, Teva reopened a California plant that it had shut down voluntarily for about a year, in part to retool to meet Food and Drug Administration manufacturing guidelines.

-By Jennifer Corbett Dooren; Dow Jones Newswires, 202-862-9294; jennifer.corbett@dowjones.com