Uveitis treatment candidate advances after mixed results

Santen is moving forward with a new drug application for sirolimus intravitreal injection (Opsiria) for the treatment of noninfectious uveitis, despite mixed results from their phase 3 trial, Sakura Study 2.

In a press release announcing topline results for Study 2, Santen stated that the difference between the low-dose (44 µg) and high-dose (440 µg) injection in terms of reducing vitreous haze was not statistically significant. However, they believe “clinical findings provide supportive evidence confirming the efficacy of the product.” Further details have not been released.

Unlike Study 2, Sakura Study 1 met its primary endpoint, showing that a 440-µg dose of the drug was significantly more effective than active control for inducing quiescence of ocular inflammation, as measured by a vitreous haze score of 0 after 5 months. Patients were randomized to receive either 440 µg, 880 µg or active control (44 µg) every other month for 6 months. Several clinically important secondary endpoints were also met in the 440-µg dose group, including a high percentage of patients successfully tapering off corticosteroids, and maintenance or improvement of BCVA during the study period. In addition to determining 440 µg as the optimal dose, the first trial also established the drug candidate’s safety.

Sirolimus, also known as rapamycin, is a bacteria-derived immunosuppressant that inhibits the activation of T cells and B cells and reduces cytokine production. It is the first-discovered compound in the mTOR inhibitor class, and has been approved since 1999 for treatment of organ transplant rejection.