WASHINGTON - Johnson & Johnson said Tuesday that a study of its experimental pain drug, fulranumab, has been halted after the Food and Drug Administration put the trial on hold over concerns that patients taking the drug could suffer increased joint damage.

The announcement follows several similar halted trials by other drug companies studying so-called nerve growth factor inhibitors. The drugs are thought to block osteoarthritis pain by reducing a protein linked to the condition. But the FDA has investigated reports that some patients treated with the drugs suffered severe osteoarthritis requiring joint replacement. Osteoarthritis is a chronic breakdown and eventual loss of cartilage in the joints.

Earlier Tuesday, a spokeswoman for AstraZeneca PLC's MedImmune unit, disclosed that the company halted an early-stage study of its drug MEDI-578 in July after Pfizer Inc. stopped a similar trial. Pfizer had halted studies of its drug, tanezumab, at the request of the FDA. And on Monday, Regeneron Pharmaceuticals Inc. and Sanofi-Aventis SA disclosed that they had also halted a study of their inhibitor drug after being contacted by the FDA.

J&J would not comment on the rate of injuries reported in the study, saying that to do so would interfere with the design of the trial. Patients were randomly assigned to receive the drug or a dummy treatment. The results of such "blinded" studies are generally not disclosed until the trial is completed.

In afternoon trading, shares of New Brunswick, N.J.-based J&J, which has Philadelphia-area operations, rose 17 cents to $62.22. AstraZeneca was up 16 cents to $46.10; it has operations near Wilmington, and MedImmune has facilities in and around Philadelphia.