FDA Approvals: Retisert, WinRho SDF, IMx Sirolimus Assay
FDA Approvals: Retisert, WinRho SDF, IMx Sirolimus Assay
April 28, 2005
Yael Waknine
The U.S. Food and Drug Administration (FDA) has approved an orphan drug indication for fluocinolone acetonide 0.59-mg intravitreal implant, allowing its use for the treatment of chronic noninfectious uveitis affecting the posterior segment of the eye; a liquid formulation of Rho(D) intravenous immune globulin [human] that eliminates the need for reconstitution; and an automated immunoassay for use in monitoring whole blood levels of sirolimus in renal transplant patients receiving antirejection therapy.
Fluocinolone Acetonide Intravitreal Implant (Retisert) for Chronic Noninfectious Uveitis
On April 8, the FDA approved an orphan drug indication for fluocinolone acetonide 0.59-mg intravitreal implant (Retisert, made by Bausch & Lomb, Inc.) for the treatment of chronic noninfectious uveitis affecting the posterior segment of the eye. Fast-track status was also granted.
The implant consists of a small drug reservoir designed to deliver sustained levels of the anti-inflammatory corticosteroid directly to the back of the eye over a period of 30 months.
The approval was based on 34-week data from two 3-year randomized, double-blind, multicenter clinical trials involving 227 patients with chronic noninfectious uveitis of at least one year's duration that affected the posterior segment of one or both eyes.
Results showed that use of the implant resulted in a significant decrease in uveitis recurrence (7% - 14% vs 40% - 54%; P < .05) and use of adjunctive therapy such as systemic corticosteroids and/or immunosuppressive therapy (5% - 10% vs 47% - 63%; P < .05) at 34 weeks compared with a 34-week pretrial period. Requirements for periocular corticosteroid injections also decreased significantly (3% - 6% vs 50% - 65%; P < .05).
In addition, a significant improvement of three or more lines of visual acuity was observed in approximately 19% to 21% of study eyes at 34 weeks postimplantation.
The most commonly reported adverse events occurring in 50% to 90% of patients included cataract progression, increased intraocular pressure (IOP), procedural complications, and eye pain. The most commonly reported nonocular adverse event was headache (31%).
According to the FDA, use of the implant is expected to cause cataracts requiring surgical removal in all phakic eyes within an average two-year period. Approximately 60% of patients will require IOP-lowering medications within 34 weeks, and 32% of patients are expected to require filtering procedures to control IOP within two years.
Caution is advised for use of ocular steroids in patients with viral eye infections (including herpes simplex) due to the potential for prolongation and exacerbation of the condition.
Liquid Formulation of Rho(D) IgG (WinRho SDF) Eliminates Reconstitution Requirement
On April 11, the FDA approved a liquid formulation of a Rho(D) intravenous immune globulin [human] product (WinRho SDF, made by Cangene Corp. and marketed by Baxter Healthcare Corp.) as an alternative to the lyophilized version that requires reconstitution prior to administration.
The plasma-derived gamma globulin (IgG) fraction contains antibodies to the Rho(D) antigen of red blood cells.
It is indicated for the treatment of nonsplenectomized, Rho(D)-positive children with chronic or acute immune thrombocytopenic purpura (ITP); adults with chronic ITP; and children and adults with ITP secondary to HIV infection. In clinical situations requiring an increase in platelet count to prevent excessive hemorrhage, it is also indicated for suppression of Rh isoimmunization.
In addition to its ITP indications, the product has recently been approved in 10 member states of the European Union for preventing hemolytic disease of the newborn. Use of the product to treat dengue hemorrhagic fever is currently being evaluated in clinical trials.
Automated Immunoassay (IMx Sirolimus) for Transplant Therapy Monitoring
On April 19, the FDA approved a microparticle enzyme immunoassay (IMx Sirolimus, made by Axis-Shield plc and marketed by Abbott Laboratories) for use with Abbott's IMx automated analyzer system for the quantitative determination of sirolimus (Rapamune, made by Wyeth Pharmaceuticals, Inc.) levels in whole blood.
The assay is indicated for use as an aid in the management of renal transplant recipients receiving sirolimus therapy.
Monitoring sirolimus concentrations is required for patients receiving concentration-controlled therapy and for patients who weigh less than 40 kg, have hepatic impairment, are receiving concurrent therapy with potent CYP3A4 inducers and inhibitors, or are likely to have altered drug metabolism.
Sirolimus is indicated for the prophylaxis of organ rejection in patients aged 13 years or older receiving renal transplantation.
Previously approved Abbott IMx tests for monitoring immunosuppressant drugs include cyclosporine and tacrolimus.
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