Clinical results data announced at the 15th EURETINA Congress meeting reported that patients receiving “X-82”, a tyrosine kinase inhibitor under development by Tyrogenex Inc, Florida, USA, had an improvement in visual acuity of 5.3 letters from baseline. The novel drug is understood to target both vascular endothelial growth factor (VEGF) and platelet derived growth factor receptor (PDGFR), potentially leading to a more potent anti-angiogenesis effect in patients with wet AMD. The presentation of the Phase I data follows an earlier announcement in May of this year for the progression of a Phase II randomized double-blind placebo controlled safety and efficacy study in 132 patients.
According to the drug sponsor, the open-label phase 1 study tested X-82 in 35 adult patients with wet AMD to evaluate safety and preliminary efficacy. Six treatment regimens at four dose levels of X-82 were evaluated and the outcomes were reported to demonstrate a trend toward higher visual acuity of +4.3 letters of the ETDRS chart, and “a trend toward decreased foveal thickness of -48 μm at 24 weeks (average of all patient data up to injection or dropout)”. Of 25 patients completing 24-weeks on the drug, the sponsor stated that 15 required no intravitreal injections of anti-VEGF and had a mean visual acuity improvement of +5.3 letters. X-82 was generally well tolerated, with 25 of 35 patients completing the full 24-week treatment period.
The US Phase II study will be run in approximately 20 centres and will have a primary outcome measure of mean change in VA from day -1 to week 52. The trial will be randomized into four 1:1:1:1 experimental arms supplemented with Eylea (aflibercept), including: group (i): 50 mg tablet of X-82 plus Eylea prn and one placebo tablet once daily; group (ii): 2 X 50 mg tablets of X-82 plus Eylea prn.; group (iii): 4 X 50 mg tablets of X-82 plus Eylea prn and, finally; (iv) a placebo comparator arm receiving placebo plus Eylea prn. All subjects will be assessed for the need for retreatment with Eylea therapy at each visit. Commenting on the advances, Michael D. Webb, president and CEO of Tyrogenex stated, “[c]urrent treatments for wet AMD require injections into the eye, and we believe an oral treatment, like X-82, may make a significant difference for patients who are battling blindness and for whom regular visits to the physician’s office are challenging.”