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For those of you who have never heard of the term, “crap gap,” before you’re not alone. I had never heard of it myself until recently and now, I’m officially in the crap gap.

So, what in the world is this “crap gap” I’m talking about? This is also referred to as an “end of dosing interval,” but it is more commonly known as the dreaded crap gap throughout the MS community. In short, the crap gap is period of time where some people may experience a transient worsening of MS symptoms prior to receiving their next disease-modifying therapy infusion or injection. For some, this time period can last only a few days, while others have reported it lasting weeks. 

My experience:

I am about three weeks out from getting my next Briumvi infusion. About a week ago, I started to feel “off.” Weird things were going on with me both physically and mentally, but I blew it off to stress of just doing too much (which is typical of me). Anyway, I noticed I would wake up in the morning feeling fairly decent and would start to go about my day. Then, without warning, my fatigue and pain levels would start to take over me, in a way that feltdifferent than my usual MS stuff (neuropathy and spasticity).

Wearing-off phenomenon in MS patients – Research study via Science Direct: sciencedirect.com A Retrospective Evaluation of Infusion Tolerability (ENAMOR) by TG Therapeutics: tgtherapeutics.com

Dr. Aaron Boster: youtu.be youtube.com/shorts Kathy Reagan Young: youtu.be Dr. Gretchen Hawley: youtube.com/shorts Other YouTube video shorts with patients discussing their crap gap experiences: youtube.com/shorts youtu.be

I felt like a slug and as the hours passed it only got worse – feeling as if I was carrying around a 500-pound backpack. My focus was also out of whack. My thought processing was annoyingly erratic – even nonexistent at times, or so it seemed. 

Typical symptoms of the crap gap include:

• Increased fatigue
• Cognitive changes – thinking, memory, cog fog, speech and word finding
• Motor function and balance
• Burning, tingling, etc.
• Overall achiness
• Mood swings

First of all, not everybody on IV or injectable DMTs will experience the symptomatic effects of crap gap. Some people remain stable, while others have reported their wearing-off symptoms were ongoing, always showing up sometime prior to their next infusion or injection. Others who had dealt with the crap gap in the early days of taking their DMT have reported their symptoms had tapered off or lessened in duration over time. 
 
Which drugs can come with a crap gap? 

The crap gap has been most commonly reported by people receiving ocrelizumab (Ocrevus), ublituximab (Briumvi), natalizumab (Tysabri), and rituximab (Rituxan). Some taking ofatumumab (Kesimpta), which is a monthly injectable, have also reported issues with the crap gap prior to their next injection.

It’s important to keep in mind that if you’re experiencing any of the symptoms or issues related to crap gap, this does not mean you’re having a relapse or going through a worsening/progressing of your MS – nor does this mean you’re having an increase in MS activity (new lesions). This also does not necessarily mean you need to switch medications either. 

Moving infusion or injection schedules to an earlier date may sound like a good idea to avoid the crap gap, but it is not. For example, one of the most serious risks or side effects from long-term use of natalizumab (Tysabri) is PML. Therefore, this is one of the key reasons doctors have set specific schedules and time frames that limit the frequency of infusions and injections to keep patients at a low PML risk, yet still offers an effective dosing regimen for treating MS. 

That being said, do talk to your doctor about any uncomfortable or strange symptoms you may be going through and, depending on the severity of such symptoms, there might be medications or other helpful remedies available to help patients better manage those temporary crap gap issues in between DMT treatments. 

I would encourage you to discuss any issues, questions, or concerns with your doctor. In the meantime, if you are currently living in the crap gap time warp, you’re not alone – I am there with you and so many others are too.

Hang in there.