FDA Approvals: Symlin, Mycamine, Fluzone

Yael Waknine

March 24, 2005

March 24, 2005 — The U.S. Food and Drug Administration (FDA) has approved pramlintide acetate injection for adjunctive use in patients with types 1 and 2 diabetes who are not adequately controlled by insulin therapy; micafungin sodium injection for Candida infection prophylaxis in patients undergoing hematopoietic stem cell transplantation and for the treatment of esophageal candidiasis; and a thimerosal-free formulation of a pediatric influenza vaccine.

Pramlintide (Symlin) Adjunct Improves Glucose Control in Type 1/2 Diabetes

On March 16, the FDA approved pramlintide acetate injection (Symlin, made by Amylin Pharmaceuticals, Inc.) for use as adjunct treatment in patients with type 1 or type 2 diabetes who have failed to achieve desired glucose control despite optimal insulin therapy.

Pramlintide is an amylinomimetic agent that modulates gastric emptying, prevents postprandial increases in plasma glucagon, and promotes satiety, leading to decreased caloric intake and potential weight loss.

The approval was based on the results of clinical studies showing that addition of pramlintide to insulin therapy reduced postprandial glucose levels and daily fluctuations, leading to improved long-term glucose control in adult patients with types 1 and 2 diabetes compared with insulin therapy alone.

Adverse events included nausea, vomiting, abdominal pain, headache, fatigue, and dizziness. The incidence and severity of nausea was highest at initiation of therapy and may be reduced by a gradual increase to recommended doses.

Because pramlintide is associated with an increased risk of insulin-induced severe hypoglycemia, its use is contraindicated in patients who cannot tell if their blood sugar is low. Its use is also contraindicated in patients with gastroparesis or with hypersensitivity to pramlintide, metacresol, D-mannitol, acetic acid, or sodium acetate.

Pramlintide and insulin should be administered separately because mixing prior to injection alters their individual pharmacokinetic parameters. Use of pramlintide has not been evaluated in a pediatric population.

Micafungin (Mycamine) for Candida Prophylaxis and Treatment

On March 16, the FDA approved micafungin sodium injection (Mycamine, made by Fujisawa Healthcare, Inc.) for prophylaxis against Candida infection in patients undergoing hematopoietic stem cell transplantation and for the treatment of esophageal candidiasis. The efficacy of the drug against infections caused by fungi other than Candida has not been established.

The approval was based in part of the results of a phase 3 clinical trial involving 518 patients with esophageal candidiasis who were randomized to receive treatment with micafungin 150 mg/day or fluconazole 200 mg/day for a median duration of 14 days. Micafungin was found to be comparable to fluconazole in terms of endoscopic cure, clinical cure, overall therapeutic cure, and mycological eradication. There was also no statistically significant difference in relapse rates between groups at two or four weeks after treatment.

A second study demonstrated that micafungin 50 mg/day was as effective as fluconazole 400 mg/day therapy for preventing Candida infection in hematopoietic stem cell transplantation recipients (80.7% vs 73.7%). Successful prophylaxis was defined as the absence of a proven, probable, or suspected systemic fungal infection through the end of therapy; therapy was terminated at a mean of 18 days, when absolute neutrophil count (ANC) reached 500 cells/mm3 or higher.

The most commonly observed adverse events were changes in liver and renal function. Possible histamine-related symptoms of rash, pruritus, facial swelling, and vasodilatation have also been reported, as well as injection-site reactions (including phlebitis and thrombophlebitis) with doses of 50 to 150 mg/day.

Serious adverse events were rare and included isolated cases of anaphylaxis and anaphylactoid hypersensitivity reactions (including shock), significant hemolysis, and hemolytic anemia.

Thimerosal-Free Pediatric Flu Shot (Fluzone) Available Next Season

On Dec. 23, the FDA approved a preservative-free formulation for a pediatric influenza virus vaccine (Fluzone, made by Aventis Pasteur, Inc.) to replace the previous single-dose 0.25 mL and 0.5 mL versions that contained trace amounts of thimerosal. The vaccine is the only one approved for use in children aged six to 35 months for influenza prophylaxis.

The company anticipates product availablity in time for the 2005-2006 influenza season.

Reviewed by Gary D. Vogin, MD

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