Last updated June 24, 2022, by Marisa Wexler, MS
ā Fact-checked by InĆŖs Martins, PhD
What is ATX-MS-1467 for MS?
ATX-MS-1467 is an experimental therapy designed to reduce autoimmune attacks in the body that has been tested in clinical trials for relapsing-remitting multiple sclerosis (RRMS).
It was originally developed by Apitope in collaboration with Merck KGaA (known as EMD Serono in North America). But Merck dropped out of the collaboration in 2016, and Apitope was acquired by Worg Pharmaceuticals in late 2021.
Worg is now seeking partners to co-develop the therapy ā renamed WP1303 ā for the treatment of multiple sclerosis (MS).
How does ATX-MS-1467 work in MS?
In MS, the body’s immune system mistakenly launches an inflammatory attack that causes damage to the myelin sheath, a fatty substance that wraps around nerve fibers and helps them send electrical signals.
ATX-MS-1467 contains a cocktail of four small peptides, or pieces, of the myelin basic protein (MBP). This protein is involved in the production of myelin and is believed to be targeted by the immune system in MS.
The basic concept of ATX-MS-1467 is to deliver small amounts of the protein that can help the immune system “get used” to it. The goal is to re-establish immune tolerance to myelin, reducing the autoimmune attack. In preclinical MS models, the therapy has been shown to substantially reduce disease severity.
How will ATX-MS-1467 be administered in MS?
ATX-MS-1467 is designed to be given via an injection into the skin ā either a subcutaneous injection, in which the therapy is delivered into the fat layer beneath the skin, or an intradermal injection, which administers it between the layers of the skin itself.
Clinical trials have evaluated doses up to 800 micrograms (mcg), given every other week.
ATX-MS-1467 in MS clinical trials
Phase 1 trials
A first-in-human Phase 1 study tested ATX-MS-1467 in six people with secondary progressive MS (SPMS). Patients received six intradermal injections of the medication at one- to two-week intervals, and were followed for three months.
The starting dose was 25 mcg. That was progressively increased to 50, 100, 400, and 800 mcg on subsequent visits to induce a gradual immune tolerance to MBP with fewer side effects. All participants then received an additional 800 mcg dose.
Results showed the experimental treatment to be well-tolerated. They also hinted that the therapy was modulating immune responses, particularly those from T-cells, against the MBP protein.
Apitope sponsored another Phase 1 trial (NCT01097668) that tested subcutaneous and intradermal injections of ATX-MS-1467 in 43 adults with RRMS.
Participants underwent a similar titration or “loading” period as those in the SPMS trial, with increasing doses of 25, 50, 100, 400, and 800 mcg administered every two weeks for eight weeks. All were then given the 800 mcg dose every two weeks for eight weeks.
Administered via intradermal injections, ATX-MS-1467 significantly reduced the number and volume of lesions with active inflammation after the 16 weeks, or about four months, of total treatment. These measures remained unchanged in the subcutaneous group, however.
Phase 2 trial
A Phase 2 trial (NCT01973491), sponsored by Merck, continued to examine the intradermal administration of ATX-MS-1467 in 37 adults with RRMS. Participants were initially given increasing doses of ATX-MS-1467 ā 50 mcg on day 1, 200 mcg, on day 15 and 800 mcg on day 29 ā and then received 800 micrograms every other week for 16 weeks.
Results from this trial were consistent with those from the earlier RRMS trial. Participants experienced a significant reduction in the number and lesions of inflammatory lesions in the brain and spinal cord. The therapy also was generally well-tolerated, with no serious adverse events reported.
Common side effects of ATX-MS-1467
The most common side effects of ATX-MS-1467 reported in clinical trials include:
- injection site reactions such as redness, itching, pain, and hardened skin
- hair loss
- diarrhea
- muscle spasm
- walking problems
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