ATX-MS-1467 is a potential disease-modifying agent with an immune-tolerating action. It consists of four short peptides derived from the myelin basic protein, and is designed to reduce myelin attacks by “switching off” the damaging autoimmune response.
The multicenter, open-label, single arm, baseline-controlled Phase 2a clinical trial (NCT01973491) evaluated the clinical and biological effects of ATX-MS-1467 in 93 patients with relapsing MS. The study also assessed the maintenance of any effects. Study objectives included changes in contrast-enhancing brain lesions and changes in annualized relapse rates.
In the study, ATX-MS-1467 was administered under the skin (intradermal injection) every two weeks for 20 weeks. Initially patients received a dose titration of 50 and 200 μg for four weeks, and then a dose of 800 μg every two weeks for 16 weeks.
The results showed that the treatment led to statistically significant reductions in total and new T1 Gadolinium-enhancing brain lesions (measured through MRI). It also significantly reduced the volume of these lesions.
In addition, the treatment improved disability as assessed by the Multiple Sclerosis Functional Composite (MSFC) score — which provides a focused, sensitive evaluation of disability in MS patients — with no serious adverse events.
ATX-MS-1467 has previously completed two Phase 1 clinical trials, which included six patients with secondary progressive MS (SPMS), and 43 patients with relapsing MS. Both clinical trials evaluated the drug’s safety and biological disease parameters. Review of MRI data showed that treatment with intradermal injection of ATX-MS-1467 led to a 78 percent decrease in contrast-enhancing brain lesions in relapsing MS patients, an early indicator of potential efficacy.
“We are delighted with these positive results that confirm both clinical findings in our Phase Ib trial as well as preclinical results showing significant decreases in MRI-detected lesions and disability in a standard multiple sclerosis model,” Apitope CEO Keith Martin said in a press release. :We will continue to progress the development of ATX-MS-1467 as a treatment for multiple sclerosis and are currently preparing for a Phase IIb placebo-controlled study to demonstrate clinical efficacy.”
Jeremy Chataway, a consultant neurologist at London’s National Hospital for Neurology and Neurosurgery, said that as chief investigator on the previous Phase Ib study, “it is pleasing to see these promising confirmatory Phase IIa results, where ATX-MS-1467 has shown both an encouraging efficacy and an excellent safety and tolerability profile. While these patients were only treated for 20 weeks, results in a Phase IIb study with a longer treatment period will be interesting.”