Psivida’s sustained-release technology is already used in diabetic macular oedema, and it should soon be able to add another eye disease, posterior uveitis, to its approved indications. The company has reported positive phase III results in the disorder, where its drug-device combo is known as Medidur – sending its share price up 21%.
A filing with the FDA is expected in the first half of 2017, once Psivida has carried out a second phase III trial in up to 150 patients in India. Eventual approval could make the company an acquisition target as its implant should help patients avoid the side effects of current therapies such as steroids and biologicals.
The group already has a relationship with Valeant’s Bausch + Lomb division, which markets its Retisert implant for posterior uveitis and Vitrasert for AIDS-related cytomegalovirus retinitis. Psivida is also developing an implant with Pfizer delivering latanoprost in patients with ocular hypertension and glaucoma.
And these partners have been two of the most acquisitive firms in recent times, although Valeant is taking something of a hiatus at the moment.
While Retisert is small, about the size of a grain of rice, Medidur is even smaller and, unlike the former, is injected rather than implanted surgically. Both implants contain the corticosteroid flucinolone acetonide, which is released gradually into the eye over up to three years.
The same drug and micro-implant are used in diabetic macular oedema, where the product is called Iluvien and is marketed by Psivida's partner Alimera Sciences – which has also been the subject of recent acquisition rumours.
Psivida will hope that gaining approval in posterior uveitis will be easier than in diabetic macular oedema, where it took four attempts to get the go-ahead (After fourth look FDA sees its way clear to approve Alimera’s Iluvien, September 29, 2014).
The latest topline phase III data should help. The 129-patient study met its primary endpoint, prevention of recurrence of disease at six months, with an impressive p value. Other endpoints looked promising, including a reduction in systemic therapies such as steroids in those taking these drugs at baseline.
|Topline phase III results at six months|
|Recurrence of disease (primary endpoint)||18.4%||78.6%||p<0.00000001|
|Improvement in visual acuity gaining 15 or more letters from baseline on ETDRS Eye Chart||23.0%||4.9%||p=0.011|
|Loss of 15 or more letters from baseline on ETDRS Eye Chart||4.6%||31.0%||p<0.0001|
|Proportion of patients on systemic therapy at baseline still receiving drugs at six months||18.2%||52.4%||p<0.01|
However, these benefits need to be weighed against an increase in intraocular pressure, a problem that is also seen with Iluvien and Retisert. At six months 27.6% of patients receiving Medidur had an increase in IOP above 21mmHg, versus 16.7% in the control group, meaning that more patients in the Medidur group needed an incisional procedure to reduce IOP – 2.3% versus none of the controls at six months.
This might be a small price to pay to treat the third most common cause of blindness in the US. However, posterior uveitis is fairly rare, affecting around 175,000 people in the US, Psivida estimates.
The company also has preclinical candidates in other diseases including wet and dry age-related macular degeneration, glaucoma and osteoarthritis. If it wants to attract the attention of the big groups it might need to show promise in these more common disorders.
This story has been updated to reflect the incidence of incisional procedures.