FDA Panel Backs Updates to Bulk Drugs List for Compounding

Troy Brown, RN

February 25, 2015

The Pharmacy Compounding Advisory Committee of the US Food and Drug Administration (FDA) voted yesterday to add squaric acid dibutyl ester, diphenylcyclopropenone, and cantharidin to its bulk drug substances list but voted not to add piracetam to the list.

The bulk drug substances list is a list of bulk drug substances that may be used to compound drug products according to section 503A of the Federal Food, Drug, and Cosmetic Act, even though they are neither the subject of a United States Pharmacopeia or National Formulary monograph nor components of drugs approved by the FDA.

On February 23, the committee voted to place thymol iodide on the list and not to place silver protein mild on the list.

Squaric Acid Dibutyl Ester Added to List

The committee voted unanimously (1 no-vote) in favor of adding squaric acid dibutyl ester to the bulk list.

Squaric acid dibutyl ester is a contact sensitizer that has been used topically to treat alopecia areata and warts. It has demonstrated effectiveness for eradicating warts from patients who have recurrent multiple warts and has no significant adverse effects. It is safe and effective for children.

Imiquimod is an alternative to squaric acid dibutyl ester but it is not approved by the FDA for treatment of children younger than 12 years.

"I would actively support both an indication for it — the indications for its use need to be real clear — as well as any adverse effects [need to] be clearly included," said voting committee member Padma Gulur, MD, professor, Department of Anesthesiology and Perioperative Care, University of California, Irvine, Orange.

Diphenylcyclopropenone Added to List

The committee voted 9 to 1 (1 no-vote) in favor of adding diphenylcyclopropenone to the bulk list.

Diphenylcyclopropenone has been used topically for the treatment of extensive alopecia areata and recalcitrant warts. It has been used in compounding for more than 30 years and is used worldwide for treatment of these conditions. It is the most effective treatment and has the best safety profile for treatment of such conditions.

"I voted 'yes' based on safety and effectiveness data provided for the indications that were discussed," Dr Gulur said.

Cantharidin Added to List

The committee voted 8 to 2 (1 no-vote) in favor of adding cantharidin to the bulk list.

Cantharidin is used to treat warts and molluscum contagiosum. It has been used since the 1950s and is currently used widely. The standard of care for its use in in-office application by a licensed healthcare professional.

"[There is a] long history of this compound being safely used, largely because when it is available to be compounded, providers...do make a quality product," said voting committee member John J. DiGiovanna, MD, staff clinician, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.

Piracetam Not Added to List

The committee voted 9 to 1 (1 no-vote) against adding piracetam to the bulk list.

Piracetam is a gamma-aminobutyric acid derivative that has been used to treat cognitive disorders, Alzheimer's disease, vertigo, and cortical myoclonus. It was synthesized in 1964 and entered clinical investigation in 1971. In rigorous trials, the results have proven lack of clinical significance. Other approved medications are available.

"It met three of the criteria [for inclusion on the list,] but it didn't show sufficient evidence of benefit," said voting committee member Jürgen Venitz, MD, PhD, committee chairperson and associate professor, Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond.

One committee member was recused from discussing or voting on three drug substances because of a conflict of interest. The remaining committee members have disclosed no relevant financial relationships.


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