OMS Manual/Chapter 8

CHAPTER 8 - OMS TREATMENTS

Description
Medical treatment for OMS can vary from child to child, generally a combination of several agents are used to reach remission or maintenance. Steroids, ivig, chemotherapy, and anti-rejection drugs are among the drugs regularly prescribed to treat OMS. Treatments all work in different ways to suppress the immune system and decrease inflammation to reduce the attack on the brain. Initially an aggressive approach using multiple agents has shown to yield better outcomes. Since OMS is a complicated and relatively unknown disease even in medical circles, it is a generally agreed upon practice in the OMS community for the patient to utilize the OMS specialist to set the treatment protocol while the local pediatrician, oncologist, neurologist, or other local practitioner implements the treatment protocol.

The current treatment protocol is documented by eighteen OMS specialists in a February 2022 publication titled "Diagnosis and Management of Opsoclonus Myoclonus Ataxia Syndrome in Children - An International Perspective". For more information about the publication, go to

Diagnosis and Management of Opsoclonus Myclonus Ataxia Syndrome in Children - An International Perspective

TREATMENTS
During the acute phase of the illness, higher doses and multiple agents are often used to hopefully halt disease activity. As the child recovers from onset, doses and the number of drugs used will decrease. If relapse occurs, doses may be increased and agents may be added until disease activity is again slowed or stopped. The course and duration of treatment is determined by severity of symptoms and expansion of b and/or t cells in the CSF. It is reasonable to expect your child to be on some combination of treatment for at least one year, though it is not uncommon for treatment to last several years. There is some controversy about right and wrong ways to treat. It is critical that you have an open dialog with your prescribing physician so you can discuss your questions and concerns or a new plan of attack if you don’t feel current treatment is effective. Most important, do what works for your child.

Intense treatment is exhausting and can be traumatic for a young child. Remember that treatment may continue for several years, every attempt should be made to lessen the anxiety experienced by the child at each hospital visit or treatment so that he/she will be able to endure. Work with your treating physician to create a plan to make hospital visits and treatment more fun. Many children’s hospitals have staff whose sole job is to entertain patients and make their experiences less stressful.

Many parents find it to be less traumatic and easier to have a port-a-cath placed in the child’s upper chest for infusions. A port allows for easy access to the blood stream for infusions. Instead of searching for veins and starting an IV, all the nurse has to do is basically “plug in” by using a special needle that pokes directly through the skin into the port. The skin over the port can be numbed using EMLA (lidocaine) cream, so that the child feels little pain when being accessed. Another benefit of a port is that it is out of the way and won’t be accidently bumped or easily pulled out as can happen if the child is upset and an IV is placed in the hand or arm.

STEROIDS
Steroids are usually the first type of treatment used to treat OMS. Commonly used to treat autoimmune disease, steroids suppress the immune system and are also some of the most powerful anti-inflammatory drugs. Generally dosing begins high and slowly tapers down as the child recovers. If the child suffers a relapse of symptoms due to illness (cold, flu, infection) or tapering too quickly, it is often necessary to increase the dose, and hold until the symptoms subside before continuing the taper. Steroids can be given in a daily dose or a pulse dose. Pulse dosing consists of steroids being given once a week or once a month. Some parents report less severe side effects with pulse dosing as opposed to a more consistent dosing schedule. Depending on the drug, steroids can be administered in pill or liquid form by mouth, injected intramuscularly, or given intravenously.

Steroids can cause irritability, elevated blood pressure, water retention, increased hunger, increased stomach acid production, susceptibility to infection, insomnia, nausea, dizziness, stunted growth, and frequent urination. Rare side effects include; cataracts, diabetes, bone weakness, bone death, and psychosis. At the beginning of treatment, you should expect weekly visits to the doctor to check blood pressure, glucose levels in the urine, and weight. A low sodium diet is highly recommended to reduce swelling due to fluid retention (Cushing’s syndrome). It is often recommended to give ranitidine (Zantac) along with steroids to prevent stomach discomfort and excess stomach acid production. Because steroids reduce calcium absorption, a calcium supplement is recommended. Never suddenly discontinue steroids, always follow a doctor’s recommendation for a tapering schedule. Sudden discontinuation of steroids will likely cause relapse and result in symptoms of steroid withdrawal.

•	ACTH: Acthar Gel is the brand name of the pharmaceutical preparation of ACTH. ACTH comes in a small vial which when refrigerated for storage is a gel, but when warmed to room temperature for administering, turns into a thick liquid. ACTH must be injected intramuscularly, usually in the upper thigh. It is recommended to alternate thighs and injection spots when giving a dose. Your hospital or home nurse should teach you how to inject ACTH. Some parents find it helpful to practice injecting with an empty syringe and an orange. The ACTH dosing schedule starts at a high dose twice a day, drops to a daily dose, then drops to a dose every other day. Once the every other day schedule begins, the amount of ACTH in the dose will begin to decrease. Acthar Gel is extremely expensive. Contact the National Organization of Rare Diseases (NORD) for assistance with paying for Acthar Gel if the child in uninsured or underinsured.

•	Prednisone: Prednisone is taken orally in pill form. In the acute phase of OMS, it will be prescribed in a daily high dose. In the event of a flare or relapse later, it may be prescribed in a pulse dose, likely given on the weekend.

•	Dexamethasone (Decadron): “Dex” is given in pill form or intravenously. It can be prescribed daily or in pulse doses consisting of 2-3 days a month in very high doses.

•	Methylprednisolone: Given intravenously in pulse doses.

IVIG - Intravenous immunoglobulin
IVIG is a pooled blood product containing IgG antibodies extracted from the plasma of over 1000 donors per infusion. IVIG is thought to work for OMS patients by reducing neuro- inflammation and temporarily “replacing’ defective immunity. The standard dose of IVIG for children with OMS is 1g/kg, a double dose is 2g/kg. The effects of IVIG can last between 2 weeks and 3 months. In children with OMS it is given every 4 weeks, but some children receive infusions more frequently. Parents of children with OMS will often report seeing slight symptoms of disease activity (specifically related behaviors)  return in the week leading up to the next infusion. Before infusion, patients are pre-medicated with Tylenol, Benadryl, and often IV Decadron. These drugs are given to prevent an allergic reaction during infusion and reduce the side effects post infusion. When a child with OMS begins treatment with ivig, they are often given two doses, back-to-back on two consecutive days. Infusion can take between 6-8 hours to complete depending on the quantity being infused and the rate of infusion.

IVIG can be given at home, while inpatient at the hospital, or in an outpatient infusion clinic. The decision often depends upon insurance, home health care availability, prescribing doctor, and the parents’ comfort level. There are several brands of IViG available; the two that are used most often are Gammaguard and Gammunex.

CHEMOTHERAPY
Chemotherapy drugs are used for their ability to temporarily eliminate either b or t cells. OMS patients don’t experience many of the risks of infection that cancer patients experience because one chemotherapy drug is used at a time eliminating only some of the overall lymphocytes. OMS patients also experience less severe side effects from chemo drugs partly because of the nature of the specific agents used and also because the doses used are smaller. As with all forms of immunosuppression, chemotherapy does increase the risk of infection and infection can potentially cause relapse.

•	Rituximab (Rituxan): Rituxan works by depleting b cells. It is given in four doses of 375mg/m2, one week apart. It can also be given in two double doses given two weeks apart. The effects of Rituxan on the B cell population last for about 6-8 months. After this time, the B cell population regenerates and in some children remission is achieved, in others repeat doses or a different agent is needed. Rituxan has a black box warning. Instances of death upon infusion due to severe allergic reaction have occurred. Rituxan has also been linked with cases of Progressive Multifocal Luekoencephalopathy (PML). PML is caused by activation of the JC virus. 90% of the population has dormant JC virus. Both death upon infusion and due to PML are extremely rare, but parents should be aware and informed. No cases of death from anaphylaxis during infusion or PML due to Rituxan have been reported in children with OMS. Rituxan can also activate dormant hepatitis B, testing for hepatitis B should be done before treatment with Rituxan. Less serious side effects of Rituxan include; nausea, headaches, fever, and chills. Many children with OMS treated with Rituxan have had few if any side effects.

•	Cyclophosphamide (Cytoxan): Cytoxan works by depleting t cells. It is given in six doses one time per month by IV. Common side effects of Cytoxan given at the protocol dose and frequency for OMS include: low white blood cell count, nausea, vomiting, fatigue, and hair thinning. A drug called Zofran can be given to prevent nausea. The doctor prescribing Cytoxan will be closely monitoring your child’s white blood cell counts and will let you know if your child is especially at risk to infection because of immunosuppression.

•	Mercaptopurine (6-MP): 6-MP also works by suppressing the immune system. It is given in tablet form. In OMS, it can be used as a drug to maintain remission for short periods of time. Common side effects include: fatigue, nausea, vomiting, and diarrhea. Cell counts will also be monitored closely while your child is being treated with 6-MP.

•	Ofatumamab: Ofatumamab is the second generation drug of Rituxan. It works in the same way as Rituxan, but is derived from human protein as opposed to mouse protein. This may make it possible to use as an alternative if your child is allergic to Rituxan. At the time of this writing, Ofatumamab is not FDA approved for use in OMS, but there has been a case in which it was successfully used to treat a child with OMS who was allergic to Rituxan.

OTHER DRUGS AND OVER THE COUNTER DRUGS COMMONLY USED
Trazadone

Melatonin

Bactrim

Calcium

Vitamins

DRUG TAPERING
OMS children will often be on steroids and IVIG treatments for years. The tapering of the drugs is one that should be closely monitored by the OMS specialist and the local doctor. Many patients find that a rapid tapering of the steroids reintroduces the OMS symptoms. It is not uncommon for the patients to require an increase in the dosage at times for the symptoms to be eliminated. Then, the tapering process can begin again. The spikes and drops of the steroid tapering process can proceed for years. Once the steroids have been eliminated, most doctors generally begin removing the IVIG treatments. This often occurs by extending the length of time between treatments until the treatment is no longer needed.

STEROID SPARING DRUGS
Steroid sparing drugs are most often used to prevent rejection in organ transplant patients. They work by suppressing the immune system. Steroid sparers may be used if your child cannot tolerate steroids because of severe side effects or if attempts to taper off of steroids have been unsuccessful because of relapses or persistent flares. They can also be used to maintain remission. Steroid sparing drugs can be difficult to dose because in order to be truly effective, they have to be given on an empty stomach, at doses that are almost exactly twelve hours apart. They also cannot be crushed, so the child must be able to swallow pills or the liquid version of the drug must be prescribed. Initially the side effects include stomach discomfort and diarrhea though these issues should resolve after a few weeks of taking the drug. The two steroid sparing agents used OMS are Cellcept (mycophenolate motefil) and Imuran (Azathioprine). These drugs also carry warnings of rare, but serious side effects including developing certain types of cancer, and increasing the risk of developing PML.