Taxol for the treatment of proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) results in retinal detachment and visual impairment due to fibroblastic proliferation in the vitreous and subsequent cellular contraction. The authors have used an in vitro model for PVR to evaluate the action of the antineoplastic drug, taxol, on chorioretinal fibroblast proliferation and contractility. Dose response curves obtained show taxol to be a potent inhibitor of both cellular events. Fifty percent inhibition of contraction and proliferation occurred at 2 X 10(-8)M and 3 X 10(-9)M, respectively. On the basis of this pharmacodynamic data, three dosage regimes were chosen to evaluate possible prevention of PVR in an animal model based on the intravitreal injection of cultured fibroblasts. These animals trials show that a single intravitreal dose of either 35 micrograms or 0.5 microgram taxol significantly reduces incidence and extent of PVR. The average grade of vitreoretinal traction at 28 days for 35 micrograms taxol and 250,000 cells was 0.4 (control 1.8); for 35 micrograms taxol and 700,000 cells, 1.0 (control 2.2); and for 0.5 microgram taxol and 250,000 cells, 1.0 (control 2.3). Delayed optic nerve damage was noted with the highest dose used, but a good therapeutic margin may exist. Long-term clinical histopathologic and electrophysiologic studies will be required. The authors conclude from these preliminary studies that taxol holds definite promise for the relief of traction retinal detachment and PVR.