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Liraglutide Has Low CVD Risk but May Be Blocked for Approval

Apr 19, 2009

Tumor data may block approval for diabetes drug liraglutide. An FDA advisory panel declined to recommend approval for the investigational diabetes drug liraglutide (Victoza), in light of

Tumor data may block approval for diabetes drug liraglutide.  An FDA advisory panel declined to recommend approval for the investigational diabetes drug liraglutide (Victoza), in light of animal studies linking the injection to thyroid cancer.

The Endocrinologic and Metabolic Drugs Advisory Committee voted 12-1 that the rodent data could apply to humans. It then split 6-6 (with one member abstaining) on the question of whether the cancer risk should preclude FDA approval.

The manufacturer of liraglutide, Novo Nordisk, assured the panel that the C-cell adenomas and carcinomas seen in rats and mice would not occur in humans, but the committee disagreed.

“The animal data [were] worrisome,” said panelist Peter Savage, M.D., an endocrinologist at the National Institutes of Health. “We didn’t see enough data in humans.”

The panel was less concerned, however, about the five cases of papillary thyroid carcinomas — the most common type of thyroid cancer — seen in humans in the sponsor’s trials.   The panel chalked those cases up to an “ascertainment bias” and voted unanimously that the cases of human thyroid cancers seen in the trials shouldn’t prevent the FDA from approving the drug.  The committee also narrowly recommended — by an 8-5 vote — that the drug’s cardiovascular risks are acceptable.

An FDA staff review found that cardiovascular events were about the same for liraglutide compared with other diabetes drugs, but slightly more events were seen in the liraglutide group when compared with placebo. Overall event rates were low.

Liraglutide, an injectable glucagon-like peptide-1 (GLP-1) mimic, is the second diabetes drug to go before a committee since the FDA ramped up its requirements for cardiovascular safety data on such products last June.  The new standards were issued in the wake of controversy over rosiglitazone (Avandia), which was shown to increase cardiovascular event risks.

(The first such drug, saxagliptin (Onglyza), got the committee’s nod in a 10-2 vote that its safety appeared acceptable.)

The Advisory Committee reviewed data from 40 clinical studies involving more than 6,800 people with Type 2 diabetes of which more than 4,600 were treated with liraglutide.

There is already an FDA-approved GLP-1 mimic, exenatide (Byetta). However, exenatide is administered twice daily, whereas liraglutide would be given once daily.

Exenatide, which is very similar to liraglutide, has not been shown to increase cancer in human populations, said Mary Parks, M.D., an endocrinologist with the FDA.

Liraglutide is also unique because it does not cause hypoglycemia or weight gain, said panel member Kathleen Wyne, M.D., Ph.D., an endocrinologist from Methodist Hospital Research Institute in Houston. Those are “the two biggest concerns” for Type 2 diabetes patients, she said.

An FDA analysis suggested the drug might actually contribute to weight loss.

According to Dr. Parks, the agency seldom approves drugs that caused cancer in two different animals across both genders.

“A lot of drugs that have multicarcinogenicity are dropped during development,” Dr. Parks said. “It’s very rare for them to be approved when they are multicarcinogenic and multigender.”

The ultimate decision on approval is up to the FDA, which does not have to follow the advice of its advisory panels, but usually does.


DID YOU KNOW: GLUCOSE KILLS BRAIN CELLS AFTER SEVERE HYPOGLYCEMIA:     Ray Swanson, MD, Chief of Neurology and Rehabilitation at the VAMC, and his colleagues have learned through animal studies that brain damage — thought to be caused by severe hypoglycemia — actually occurs when glucose is administered to treat the low blood sugar.  Furthermore, it appears as though high levels of glucose given right after hypoglycemia is more damaging than a slower return to normal glucose levels.  Even though these studies were in animal models and haven’t been investigated in humans yet, the findings were surprising and may have clinical relevance for the treatment of hypoglycemia in an emergency room situation.  Dr. Swanson’s full study can be found in the Journal of Clinical Investigation[ journal article ]   [ Dr. Swanson ]