Ocriplasmin: Proteolytic enzyme for eye disorder

Jetrea (ocriplasmin—ThromboGenics)

FDA and ThromboGenics announced the approval of ocriplasmin (Jetrea) for the treatment of symptomatic vitreomacular adhesion, a progressive sight-threatening condition. This is the first pharmacological agent to be approved for this indication.

Ocriplasmin, formally known as microplasmin, is a proteolytic enzyme that breaks down proteins in the eye responsible for vitreomacular adhesion. It dissolves the protein matrix responsible for the vitreomacular adhesion by breaking down components of the vitreous body and the vitreoretinal interface. Ocriplasmin is an intravitreal injection that should be administered by qualified physicians. The injection will be available in January 2013.

Vitreomacular adhesion

Vitreomacular adhesion generally occurs with aging and can contribute to eye problems if the vitreous starts to move away from the macula, resulting in damage of the macula because of pulling or tugging. Patients may experience symptoms such as blurring of visual acuity with central visual-field defects.

Vitrectomy is the primary treatment to manage symptomatic vitreomacular adhesion. Because it is a surgical procedure and associated with various risks such as infection, retinal detachment, hemorrhage, and cataract, vitrectomy is not performed until there is a clinically significant loss of vision.

Nonsurgical approaches such as chondroitinase, dispase, and hyaluronidase have been tested for management of symptomatic vitreomacular adhesion, but these treatments were abandoned because of lack of efficacy, safety concerns, or both.

Ocriplasmin is the first pharmacologic agent to show efficacy in preclinical and clinical studies, and its approval offers patients a nonsurgical option to manage this serious eye condition.

Clinical efficacy, safety

Approval was based on data from two Phase III clinical studies involving 652 patients with symptomatic vitreomacular adhesion. Patients were randomly assigned to receive a single injection of ocriplasmin (n = 464) or placebo (n = 188) into the eye and were evaluated over the next 28 days for efficacy.

Results from the trials showed that ocriplasmin was superior to placebo for achieving resolution of symptomatic vitreomacular adhesion at day 28 (26.5% vs. 10.1%, P < 0.01), with results sustained through month 6. In addition, the number of patients with at least a 3-line increase in visual acuity was numerically higher in the ocriplasmin group compared with placebo in study 1 (12.8% vs. 8.4%) and study 2 (11.8% vs. 3.8%).

Treatment with ocriplasmin was associated with mainly transient ocular adverse events. The most common adverse events reported in patients treated with ocriplasmin were eye floaters, bleeding of the conjunctiva, eye pain, photopsia, blurred vision, unclear vision, vision loss, retinal edema, and macular edema.

Ocriplasmin (Jetrea)

Manufacturer: ThromboGenics

Drug class: A proteolytic enzyme

Indication: Treatment of symptomatic vitreomacular adhesion

Dosage: 0.125 mg (0.1 mL of the diluted solution) administered by intravitreal injection to the affected eye once as a single dose

Of note: Warnings and precautions for ocriplasmin include intraocular inflammation/infection, intraocular hemorrhage, and increased intraocular pressure; potential for lens subluxation; retinal breaks; yellowish vision; and decreases in vision as a result of progression of the condition which may require surgical intervention.

Patient counseling

Instruct patients to report eye pain, redness of the eye, photophobia, and blurred or decreased vision after the administration of the injection immediately. Because of the potential for temporary visual impairment following the injection, advise patients not to operate heavy machinery until the visual impairment has resolved.