The panel, in a 13 to 3 vote, recommended the approval of Sanofi and Regeneron Pharmaceuticals’ drug, alirocumab. On Wednesday, the committee will turn to Amgen’s drug, evolocumab. The F.D.A. usually follows the recommendations of its advisory panels, but not always. The agency says that if it approves the drugs based on their effects on cholesterol, the approval will not be rescinded even if trials now underway fail to show the drugs reduce the risk of heart attacks and deaths.

Once a drug is approved doctors can prescribe it to patients other than those for whom it was intended, although insurers generally will not pay.

The drugs are injected every two weeks or once a month, depending on the formulation. The companies are asking that they be approved for use in three groups: patients with high levels of LDL cholesterol who cannot lower it enough with statins, the mainstay drug for cholesterol lowering first introduced in the late 1980s; people at very high risk because they have already had a heart attack or have diabetes and cannot get their levels low enough with statins; and people with high levels of LDL who cannot tolerate statins. Doctors often aim for LDL levels of 70 for people at high risk.

The problem for the expert group was to decide if there was enough evidence to approve the Sanofi drug without waiting for results from the large clinical trials. Those who voted no said drugs should not be approved until clinical trials established their efficacy, and voiced the worry that people participating in the trials would drop out once the drugs were approved so they could be sure to get the medicine, not a placebo.

“We need clinical outcomes,” said Dr. Peter Wilson of Emory University.

Some on the panel felt comfortable recommending approval only for a narrow group of people with a genetic condition, heterozygousfamilial hypercholesterolemia, who cannot control their cholesterol with statins alone. Others favored allowing use of the drug by the much larger group of people at high risk of heart disease for whom statins are insufficient.