H.P. Acthar Gel

H.P. Acthar Gel (adrenocorticotropic hormone or ACTH), marketed by Mallinckrodt Pharmaceuticals, is a hormone that works by stimulating the body to produce more adrenocortical hormones. It is used to treat conditions caused by allergies, breathing issues, blood or endocrine problems, arthritis, skin or eye problems, bowel inflammation, certain cancers, and multiple sclerosis (MS).

For MS patients, Acthar Gel has been approved by the U.S. Food and Drug Administration for short-term treatment of acute relapses or flare-ups. Studies have shown that the gel is effective in speeding recovery from an MS relapse, but there is no evidence that it affects the natural progression of the disease or its outcome.

Acthar Gel is available for people with MS who do not tolerate the side effects from high doses of corticosteroids, prefer self-injection, have been treated without success with corticosteroids, or have difficulty receiving medication into their bloodstream.

For acute MS exacerbations, 80–120 units of Acthar Gel are usually injected once daily for two to three weeks, and then the dose is gradually decreased. If it is administered at home, the injection procedures must be carefully followed

How H.P. Acthar Gel works

How Acthar Gel works is not entirely understood, but its anti-inflammatory properties is thought to help inhibit the immune system’s ability to attack myelin, the fatty substance that surrounds and insulates nerve fibers.

Acthar Gel’s active ingredient is ACTH, which is a peptide or small protein that binds to melanocortin receptors (MCR) on immune cells. This initiates a signaling cascade that leads to the inhibition of NF-ĸB, which then suppresses the reproduction of inflammatory cells.

ACTH can also bind to MCR receptors that are present on adrenal cortical cells found in the adrenal glands above the kidneys. This binding stimulates the production of the hormone cortisol. Because cortisol is a corticosteroid — which is also used to treat acute MS relapses — Acthar Gel’s benefit might partly be due to its ability to increase the production of corticosteroids.

H.P. Acthar Gel in clinical trials

Methylprednisolone and other corticosteroids are known to cause neuropsychiatric side effects, such as mood changes. A case series involved six patients with relapsing-remittent MS (RRMS) who had previously experienced detrimental mood changes with methylprednisolone treatment. All six were injected with 80 iu of Acthar Gel per day. MS symptoms improved, and the rate of neuropsychiatric side effects was low.

In a randomized trial, 20 participants with MS injected themselves with 80 iu of Acthar Gel per day either under the skin or into a muscle for five consecutive days. Patients rated their symptoms on a patient global impression of change scale with scores ranging from one (very much improved) to seven (very much worse). On day 14, 77.7 percent of patients who injected the treatment into their muscle, and 44.4 percent of those who injected it under their skin rated their overall symptoms as very much improved or much improved. Because the group sizes were small, the difference was not statistically significant. Injection into the muscle was associated with more injection site pain than under-the-skin injection.

Several clinical trials assessing Acthar Gel for MS are currently recruiting patients.

An open-label trial (NCT01900093) aims to evaluate the response to Acthar Gel treatment in 10 adult patients who have failed to make adequate recovery after treatment with methylprednisolone. Participants will receive 80 iu of Acthar Gel for 14 days in this trial, based in New York, U.S.

A randomized Phase 4 clinical trial (NCT03126760) plans to assess the efficacy and safety of Acthar Gel in 66 adult patients with RRMS. Patients who experience a relapse will receive treatment with high doses of corticosteroids. Those whose symptoms do not improve upon corticosteroid treatment will be randomized to receive either 80 iu of Acthar Gel or a placebo for 14 days. The trial is recruiting participants across the U.S.

Another randomized Phase 4 clinical trial (NCT02446886) in New York plans to evaluate the effect of Acthar Gel on the myelination of nerve fibers. Participants will receive either 80 iu of Acthar Gel for three to five days, or 80 iu of Acthar Gel for three to five days followed by monthly three-day treatments for 12 months.

A randomized Phase 2 clinical trial (NCT01950234) aims to assess the safety and efficacy of repeated treatments with Acthar Gel. Participants will receive either Acthar Gel or a placebo for three consecutive days per month. The trial is recruiting MS patients in Minnesota, North Dakota, and Wisconsin.

Additional information

The most common side effects of Acthar Gel are similar to those of steroids and include fluid retention, changes in blood sugar, increased blood pressure, behavior and mood changes, and changes in appetite and weight.


Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.


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