Kesimpta, We Need to Talk…
…and it’s not me, it’s you.
I have officially “broken up” with my Disease Modifying Therapy (DMT) for MS. I’ve been taking Kesimpta since September 2021. I was diagnosed with MS on August 17, 2021, and this was my first DMT. I no longer have a DMT in common with one of my favourite podcasters, Jamie-Lynn Sigler.
Dr. Aaron Boster, an MS-specialist neurologist with an incredibly informative YouTube channel (seriously, if you have MS and you aren’t already following him, go give him a follow), says that there are six conditions under which a patient should consider switching DMTs for MS:
A breakthrough clinical attack - this means that the patient has experienced a clinical relapse with new MS symptoms which may be temporary or permanent.
A breakthrough radiographic attack - this means that while the patient has not developed new MS symptoms, a new lesion has appeared on the patient’s MRI scans.
Worsening neurological condition - MS patients are typically administered a neurological exam during our annual appointments with our neurologists. This assesses nerve function, including balance, coordination, vision, strength, and reflexes to identify signs of myelin damage. Worsening of any of these key indicators is cause for concern.
Poor tolerability - when a DMT is causing side effects which adversely affect the patient’s quality of life.
When the DMT is no longer considered safe.
The development of new more effective DMTs.
In the past few months I’ve checked off at least one and potentially three of these conditions, warranting a reconsideration of my DMT.
As you will know if you read my recent blog post titled: “Plot Twist: Surviving a Catastrophic Gastrointestinal Hemorrhage and Discovering my Immune System is at it Again”, on January 27, 2026, I had a near death experience where I lost over half of my blood volume from a gastrointestinal hemorrhage. I had a colonoscopy while hospitalized which failed to locate the source of the gastrointestinal hemorrhage, but which found mild inflammation in my cecum. This is where the small intestine and large intestine meet. The biopsies performed during the scope returned evidence of Inflammatory Bowel Disease (IBD).
I had a follow-up appointment with my gastroenterologist on March 5, 2026, and Dr. Ghazala raised the concern that Kesimpta may have induced IBD. He advised that I am his third patient who has developed IBD while taking Kesimpta. He also advised that he is not satisfied that IBD explains my catastrophic hemorrhage, as the inflammation that he observed during my colonoscopy was limited to one small area and was mild. The inflammation observed during my scope is more consistent with Crohn’s Disease than with Ulcerative Colitis. Major hemorrhaging is not typical of Crohn’s Disease, and particularly in the absence of other symptoms (e.g., diarrhea, pain, cramping, unexplained weight loss) and in the absence of significant inflammation observable on scope. Dr. Ghazala referred me for an upper endoscopy (esophagogastroduodenoscopy) as the next step in my diagnostic journey, in the hopes that it might shed some light on the cause of my hemorrhage. My upper endoscopy occurred on April 13, 2026. It came back completely normal. So I’m still in the dark on the cause of my catastrophic hemorrhage. Dr. Ghazala is referring me for a capsule endoscopy next. This will allow him to visualize my small intestine, which at this point is the only area of my gastrointestinal tract yet to be visualized. I will have to swallow a small camera and it will transmit pictures to a device that I will keep with me on the day of the procedure. I’m keeping my fingers and toes crossed that this capsule endoscopy actually provides some answers. I found myself weirdly disappointed that the upper endoscopy was completely normal. On the one hand, that’s great news, but on the other hand it is seriously distressing to not know what caused a near fatal gastrointestinal hemorrhage. Without knowing what caused it, no one can provide any reassurance to me that it won’t happen again.
A date with one of these fancy pill cameras is the next step in my diagnostic journey following a catastrophic gastrointestinal hemorrhage in January.
I had my annual appointment with my neurologist on March 24, 2026, and he confirmed that there is a known but rare risk with DMTs that deplete CD20+ B cells, like Rituxin (rituximab), Ocrevus (ocrelizumab), Kesimpta (ofatumumab), and Briumvi (ublituximab-xiiy) that they can trigger a “Crohn's-like Disease”, a drug-induced immune-mediated colitis. B cells play a role in maintaining the gut mucosal barrier by producing protective IgA and IgM. When these DMTs kill CD20+ B cells, this can disrupt the gut’s immune balance. Dr. Schneider was careful to clarify that having one autoimmune disease puts me at a higher risk of developing another. He cannot guarantee that this is Kesimpta-induced immune-mediated colitis. It is also possible that I simply have the bad luck of having both MS and Crohn’s Disease. However, there is enough of a probability that Kesimpta is a culprit here that it made sense to cease this treatment immediately. If this is Kesimpta-induced immune-mediated colitis, then it should resolve once my B cells recover. If I truly have Crohn’s Disease, then it won’t go away with discontinuing Kesimpta.
The possibility that Kesimpta has induced “Crohn’s-like Disease” potentially checks off two of the conditions which Dr. Boster suggest warrant a re-evaluation of DMT, #4 - poor tolerability, and #5 - when the DMT is no longer considered safe.
In addition, my annual MRI on February 3, 2026, returned evidence of a small new spinal cord lesion at the C4 level. This checks off Dr. Boster’s condition #2 - a breakthrough radiographic attack. Based on clinical trial data, Kesimpta has an Annualized Relapse Rate (ARR) between 0.05 and 0.1. This corresponds to one relapse every 10 to 20 years. My relapse occurred sometime between January 2, 2024, and February 3, 2026, so sometime between 2.5 and 4.5 years on Kesimpta. This is too early. I’ve never met an analogy that I didn’t love, so think of the decision to start a high efficacy DMT like Kesimpta as akin to the decision to install a high-quality transmission in your car. A good transmission should last a long time, often 150,000-200,000km without major issues. If it starts failing after 25,000-50,000km you are bound to conclude that something isn’t right. Either there’s a problem with the part or with how the part is working in your car. I wouldn’t keep driving a car with a failing transmission just because I installed a really good one, so I’m not going to stick with a DMT that should have bought me many years of quiet MS in the face of evidence that it isn’t performing as expected.
I’ll summarize my time on Kesimpta with the good, the bad, and the ugly.
The good:
Kesimpta is about as convenient as MS DMTs come. It is a once monthly self-injection. The injections themselves are relatively painless. Novartis’ support program, the Kesimpta Go Program (this is its Canadian branch, it is the Kesimpta Alongside Program in USA), is excellent. They took care of all of the paperwork to ensure coordination between my neurologist, my insurance company, my husband’s insurance company, the pharmacy, and me all ran smoothly. I liked that I wasn’t tied to an infusion schedule. I was able to travel with my DMT. It made it possible to build my treatment around my life, as opposed to having to build my life around my treatment.
The bad:
I believe that Kesimpta caused me constipation. I can’t rule out that this was caused by my MS itself. However, I started struggling with this immediately after starting the DMT. I’ll be interested to see if it resolves as the drug clears my system.
I regained a significant portion of the weight that I had lost before starting on Kesimpta throughout the last 4.5 years. Not all of it. I’m still down 17lbs from where I started in January 2021. But I’ve been frustrated to regain much of what I had lost. I have found it harder to lose weight while taking Kesimpta. Weight gain is a common side effect complained about on the online support groups for those taking Kesimpta for MS, though Novartis doesn’t include it in the list of recognized side effects.
I experienced an increase in hair shedding while taking Kesimpta, though this hasn’t translated into any significant hair thinning. Once again, this is a common side effect complained about on the online support groups, but not recognized as a side effect by Novartis.
The ugly:
Kesimpta may have caused me drug-induced immune-mediated colitis, and a resulting catastrophic hemorrhage. I reported my hemorrhage and development of apparent IBD to Novartis as a possible drug side effect.
It also didn’t work as desired for me, having developed a new spinal lesion much earlier than I would have expected given the ARR for Kesimpta.
So what’s the plan now?
After consulting with my neurologist, I’ve decided to switch to a different DMT. I’ll be switching to Mavenclad (cladribine). I’m already finding EMD Serono’s support program, ADVEVA, very helpful. Mavenclad is a selective immune reconstitution therapy. It works by targeting and temporarily reducing B and T lymphocytes. B and T lymphocytes mistakenly attack the protective myelin that insulates nerve cell axons in those living with MS. Mavenclad is a chemotherapy agent which has been repurposed for MS. It accumulates in B and T lymphocytes and mimics DNA, thereby becoming incorporated into the cell’s DNA. This triggers cell death (apoptosis). Over time, the immune system rebuilds these cells, but in a less autoreactive form. Think of it like doing a hard reboot on a computer that’s acting glitchy. Rather than leaving the system running and fixing bugs as they pop up, we’re shutting the system down, clearing out the malfunctioning parts, and hoping that things run more smoothly when back online. It’s more disruptive, but the goal is a more stable situation in the long run. Dr. Boster refers to Mavenclad as “the king of the pills”. Most of the DMTs in pill form are considered moderate-efficacy, but Mavenclad is grouped in the high-efficacy group.
EMD Serono’s marketing materials would have you thinking that they’re advertising a beach vacation rather than an aggressive MS treatment.
Before starting Mavenclad, infection screening and baseline bloodwork is required. I have already completed this step. I had to be screened for Hepatitis, HIV, and TB. They also check liver function and obtain a complete blood count, primarily to assess baseline lymphocyte counts. A number of vaccines are recommended before starting Mavenclad. Thankfully, I’m up to date on my vaccinations, even opting to get my Shingrix vaccine at the ripe old age of 37 (you can read my blog post titled: “Shingles: The Uninvited Guest at the MS Party” to learn more about why vaccinating against shingles early is prudent for most people living with MS). The need for additional vaccinations is a frequent bottleneck in the process of starting Mavenclad. At this point, I am just waiting on the green light from insurance before I can begin my new DMT.
Mavenclad is a discontinuous therapy. I will take it for 5 days. Four weeks later, I will once again take it for 5 days. The following year, I will repeat this process. After that, I won’t have to take a DMT again until and unless I develop new MS disease activity, in the form of a clinical attack, a radiographic attack, or worsening neurological condition. Mavenclad aims for long-lasting MS disease control without ongoing medication. I like the idea of not being in a state of consistent and continuous immune suppression. Mavenclad has an ARR between 0.09 and 0.14, so it should, if it’s working for me, get me 7-11 years of quiet MS. The ARR is a population average, and not a personal prediction. However, it is a helpful metric in understanding the efficacy of a DMT and whether it is working to expectations.
Mavenclad comes with its own long list of potential side effects. Lymphopenia (a low lymphocyte count) is a serious and expected side effect, and evidence that Mavenclad is acting as expected. Lymphopenia weakens the immune system and it can lead to frequent, long-lasting, or unusual infections. While in a state of lymphopenia, I will be more susceptible to viruses, bacteria, fungi, and parasites. I will have to be extra careful while in a state of lymphopenia, including frequent hand washing, wearing a mask when in indoor crowded places, and avoiding high risk environments (no trips to Great Wolf Lodge during periods of lymphopenia, sorry kiddo!). I’m keen to start Mavenclad as soon as possible because starting in the spring will mean that my period of most significant immune suppression will land in the summer and away from cold and flu season. The good news is that lymphopenia is a temporary side effect, and one that will be carefully monitored with regular bloodwork. A delayed recovery from lymphopenia can delay the second year’s dosing schedule. Nausea, fatigue, and headaches are very common side effects of Mavenclad. Rash, hair thinning/loss, abdominal pain, toothache, back pain, and anxiety are all common side effects of Mavenclad. Mavenclad has two black box warnings from the FDA regarding an increased risk of malignancies (cancer) and the risk of teratogenicity (fetal harm). Our family is complete, so I’m not worried about the risk of teratogenicity, but it is concerning that clinical studies showed a higher incidence of cancer in patients treated with Mavenclad compared to those taking a placebo. There is also a small risk for liver injury. While I try not to get bogged down in the “rare, but scary” side effects, and instead focus on the more common side effects, it’s hard not to note them with a certain degree of fright when I have potentially just seen some of the worst of the “rare, but scary” side effects that Kesimpta has to offer.
Mavenclad is insanely expensive. It costs $3,212 per tablet here in Ontario, for a total of $54,604 per year for my dosing schedule. Keep your fingers and toes crossed for me that our insurers agree to cover it and that EMD Serono’s patient assistance agrees to cover the share beyond the maximums of our insurance coverage. Best case scenario, this medication will leave me with absolutely no coverage for anything else. Let’s hope that I don’t really have Crohn’s Disease, because there’ll be no benefits left to cover treating it. The upside, however, is that I could have many treatment free years after two costly treatment years.
Switching to a new DMT is both scary and exciting. On the one hand, there are lots of gnarly potential side effects, and there’s uncertainty around which of these side effects I will experience. But on the other hand, Mavenclad may work better for me than Kesimpta did and give me a good long period of remission. Making the decision to switch is both uncomfortable and empowering. Choosing an option is difficult when every option comes with risk and significant downsides. This has me reflecting back on choosing my first DMT, which I wrote about in the blog post titled: “It’s a Multiple Choice Exam, and Wrong Answers will be Penalized”. It’s 4.5 years later, but the sentiment I had then about the high stakes multiple choice exam rings true now too. There’s no way of knowing whether I’m making the “right” decision until I gain the benefit of hindsight. And even then, I can never know what the path not travelled would have looked like.
For now I’m playing the waiting game. Waiting for my planned MS treatment to be approved. Waiting for my capsule endoscopy to be scheduled. And waiting for Kesimpta to clear my system and for my B cells to recover so that we can assess whether I really have Crohn’s Disease or whether my gastrointestinal symptoms can be chalked up to Kesimpta-induced immune-mediated colitis.
