Injection sits at the center of this dementia and brain health question.
A class of biologic injections known as anti-interleukin-23 therapies is putting a remarkable number of Crohn’s disease patients into sustained clinical remission, with some maintaining remission for three years or longer after starting treatment. Risankizumab, marketed as Skyrizi, became the first IL-23 inhibitor approved for moderate-to-severe Crohn’s disease and has shown in extension studies that roughly 60 percent of patients who responded to induction therapy maintained deep remission through 152 weeks of treatment, a result that has shifted how gastroenterologists approach this notoriously difficult condition.
For the millions of people living with Crohn’s, and for caregivers who often manage complex medication regimens alongside other conditions like dementia, this development matters on a practical level. Fewer flares mean fewer emergency hospitalizations, less cognitive strain from chronic pain and inflammation, and a more stable daily routine. This article covers how these injections work, who they are best suited for, how they compare to older biologics, the connection between gut inflammation and brain health, and what limitations patients should understand before starting treatment.
Table of Contents
- How Is a Single Injection Putting Crohn’s Disease Into Long-Term Remission?
- Who Should Consider IL-23 Inhibitor Therapy and Who Should Not
- The Gut-Brain Axis and Why Crohn’s Remission Matters for Cognitive Health
- Comparing IL-23 Inhibitors to Other Crohn’s Biologics in Practice
- Limitations and Risks That Patients Need to Understand
- Managing the Injection Schedule in a Caregiving Context
- What Is Next for Crohn’s Treatment and Where IL-23 Inhibitors Fit
- Conclusion
- Frequently Asked Questions
How Is a Single Injection Putting Crohn’s Disease Into Long-Term Remission?
The injection works by targeting interleukin-23, a specific protein in the immune system that drives the chronic inflammation responsible for Crohn’s disease symptoms. Unlike older biologics such as infliximab or adalimumab, which block tumor necrosis factor (TNF) broadly, IL-23 inhibitors are more selective. They neutralize a single subunit of the IL-23 cytokine called p19, which means the immune system retains more of its normal function while the specific inflammatory cascade causing bowel damage gets shut down. Risankizumab is administered as intravenous infusions during the first 12 weeks, then transitions to subcutaneous injections every eight weeks that patients can give themselves at home. The clinical trial data behind this is substantial.
In the ADVANCE and MOTIVATE trials, about 45 percent of patients achieved clinical remission by week 12 on induction dosing. Those who responded then entered the FORTIFY maintenance trial, where 52 percent maintained remission at one year on the standard dose. Extension data presented at gastroenterology conferences has tracked patients out to three years, with remission rates holding steady. For comparison, adalimumab, the previous standard biologic, showed remission rates closer to 36 percent at one year in its pivotal Crohn’s trials. A patient named David, profiled in a Crohn’s and Colitis Foundation case study, described going from eight daily bowel movements and constant fatigue to what he called “forgetting I have Crohn’s” within four months of starting risankizumab.
Who Should Consider IL-23 Inhibitor Therapy and Who Should Not
These injections are approved for adults with moderate-to-severe Crohn’s disease, and gastroenterologists are increasingly reaching for them as a first-line biologic rather than reserving them for patients who have already failed TNF inhibitors. The American Gastroenterological Association’s 2023 guidelines conditionally recommend IL-23 inhibitors as appropriate first-line advanced therapy, placing them on equal footing with anti-TNF agents and integrin inhibitors like vedolizumab for newly diagnosed patients needing biologic treatment. However, not every Crohn’s patient is a candidate. Patients with active, serious infections should not start treatment until the infection is resolved, and those with a history of active tuberculosis need screening and treatment before beginning therapy.
Patients who have fistulizing Crohn’s may see some benefit, but the evidence is less robust than for luminal disease, and a gastroenterologist may recommend combination approaches. For older adults, particularly those also managing dementia or cognitive decline, the decision involves weighing the reduced injection frequency against the patient’s ability to adhere to the schedule or the caregiver’s ability to administer shots. If a patient cannot reliably self-inject and has no caregiver assistance, the every-eight-week schedule may still require clinic visits, which can be logistically difficult for those with mobility or cognitive limitations.
The Gut-Brain Axis and Why Crohn’s Remission Matters for Cognitive Health
research into the gut-brain axis has made it increasingly clear that chronic intestinal inflammation does not stay contained to the digestive tract. Inflammatory cytokines produced during active Crohn’s disease, including IL-23 itself, can cross the blood-brain barrier and contribute to neuroinflammation. A 2021 study published in the journal Inflammatory Bowel Diseases found that patients with active Crohn’s had measurably higher rates of cognitive complaints, including brain fog, difficulty concentrating, and short-term memory problems, compared to those in remission. For patients who are simultaneously managing early-stage dementia or mild cognitive impairment, uncontrolled Crohn’s inflammation may be compounding their cognitive burden.
The chronic pain, disrupted sleep from nighttime bowel symptoms, malnutrition from poor absorption, and the systemic inflammatory load all create conditions that accelerate cognitive decline. A gastroenterologist at Mount Sinai, Dr. Jean-Frederic Colombel, has noted in published interviews that achieving deep remission in IBD patients does more than heal the gut; it reduces the total inflammatory burden on every organ system, including the brain. Caregivers who have noticed that their loved one’s confusion or agitation worsens during Crohn’s flares are observing this connection firsthand.
Comparing IL-23 Inhibitors to Other Crohn’s Biologics in Practice
Patients and caregivers often face a confusing landscape of biologic options, and the practical differences between them matter as much as the efficacy data. Anti-TNF drugs like infliximab require intravenous infusions every six to eight weeks at an infusion center, which means regular transportation and time commitments. Adalimumab can be self-injected at home every two weeks, which is more frequent than risankizumab’s every-eight-week maintenance schedule. Vedolizumab, which targets gut-specific integrin receptors, requires intravenous infusions initially, though a subcutaneous formulation is now available. The safety tradeoff is notable.
Anti-TNF agents carry well-documented risks of serious infections, reactivation of latent tuberculosis, and a small but real increased risk of lymphoma with long-term use. IL-23 inhibitors, based on data through three years, have shown lower rates of serious infections compared to anti-TNF drugs. In the FORTIFY trial, serious infection rates were about 3 percent per year for risankizumab versus historical rates of 5 to 7 percent for infliximab. For elderly patients or those on immunosuppressive medications for other conditions, this lower infection risk can be a deciding factor. The tradeoff is cost. Without insurance, risankizumab runs roughly $20,000 to $25,000 per year, and while manufacturer assistance programs exist, navigating them requires paperwork that can be a burden for caregivers already stretched thin.
Limitations and Risks That Patients Need to Understand
No biologic works for everyone, and IL-23 inhibitors are not an exception. Roughly 40 to 45 percent of patients do not achieve remission during the induction phase, and among those who do respond initially, some will lose response over time. Unlike anti-TNF agents, where loss of response is frequently tied to the development of anti-drug antibodies, the mechanisms behind loss of response to IL-23 inhibitors are less well understood, which makes it harder for doctors to predict who will maintain long-term benefit. There are also conditions where the data simply does not exist yet.
Patients with Crohn’s disease complicated by primary sclerosing cholangitis, extensive surgical history with short bowel syndrome, or significant stricturing disease may not see the same benefit as those with primarily inflammatory disease. The three-year remission data, while encouraging, comes from controlled trial populations that tend to exclude patients with the most complex disease phenotypes. Patients should also be aware that stopping therapy, even after years of remission, carries a high risk of relapse. A study of anti-TNF discontinuation showed relapse rates above 50 percent within one year, and while equivalent long-term discontinuation data for IL-23 inhibitors is still being collected, gastroenterologists generally counsel patients to continue therapy indefinitely.
Managing the Injection Schedule in a Caregiving Context
For caregivers managing both Crohn’s disease treatment and dementia care for the same individual, or caring for someone with Crohn’s who also has cognitive impairment, the eight-week injection cycle requires planning. Setting calendar reminders, coordinating with the prescribing gastroenterologist’s office for refill timing, and ensuring proper storage of the medication in the refrigerator are all tasks that fall to the caregiver.
One approach used by home health agencies is to align the injection schedule with other recurring medical appointments, reducing the number of separate care tasks to track. If the patient previously self-administered their injections but is losing the ability to do so due to cognitive decline, the transition period needs to be handled carefully. Gastroenterology nurse specialists can train caregivers on proper subcutaneous injection technique, and most manufacturer patient support programs include nurse educator visits at no additional cost.
What Is Next for Crohn’s Treatment and Where IL-23 Inhibitors Fit
The pipeline for Crohn’s disease treatment is more active than it has been in decades. Guselkumab, another IL-23 inhibitor already approved for psoriasis, has completed phase 3 trials for Crohn’s and is expected to reach the market soon, providing another option in the class. Combination biologic strategies, pairing an IL-23 inhibitor with vedolizumab, are being studied in clinical trials for patients with refractory disease.
Further out, oral small-molecule JAK inhibitors like upadacitinib, already approved for ulcerative colitis, are being evaluated for Crohn’s and could eventually offer a pill-based alternative to injections. For the near term, IL-23 inhibitors represent the clearest advance in Crohn’s treatment in over a decade. Their combination of strong efficacy data, favorable safety profile, and manageable dosing schedule makes them particularly well suited for patients whose care involves multiple conditions and multiple caregivers. As longer-term real-world data accumulates outside of clinical trials, gastroenterologists expect the remission durability numbers to become even more reliable for guiding treatment decisions.
Conclusion
IL-23 inhibitor injections, led by risankizumab, have demonstrated the ability to put a meaningful percentage of Crohn’s disease patients into sustained remission lasting three years and beyond. For patients and caregivers navigating the intersection of inflammatory bowel disease and cognitive health challenges, the reduced flare frequency, lower infection risk compared to older biologics, and manageable injection schedule offer real practical advantages. The connection between gut inflammation and brain health makes achieving and maintaining Crohn’s remission not just a gastrointestinal goal but a cognitive one as well.
Anyone considering this treatment should have a detailed conversation with their gastroenterologist about their specific disease phenotype, prior treatment history, and overall care situation. For caregivers, understanding the injection schedule, storage requirements, and signs of potential complications like infection is essential. The data supports optimism, but informed decision-making, not enthusiasm alone, should guide the path forward.
Frequently Asked Questions
How long does it take for risankizumab to start working for Crohn’s disease?
Most patients undergo a 12-week induction phase with three intravenous infusions. Clinical improvement is often noticed by week 4 to 8, but full assessment of response happens at week 12 before transitioning to maintenance injections.
Can IL-23 inhibitors be used alongside immunosuppressants like azathioprine?
Some gastroenterologists do use combination therapy during induction, but unlike anti-TNF agents, IL-23 inhibitors do not appear to require concomitant immunosuppression to maintain efficacy. The decision depends on individual patient factors and should be discussed with the prescribing physician.
Are there cognitive side effects from IL-23 inhibitor injections?
Clinical trial data has not identified cognitive impairment as a side effect of risankizumab. In fact, by reducing systemic inflammation, patients often report improvements in brain fog and mental clarity that were being driven by active Crohn’s disease.
What happens if a patient misses a maintenance injection?
Missing a single dose does not automatically mean a flare will occur, but patients should contact their gastroenterologist’s office as soon as possible to reschedule. The drug has a relatively long half-life, so a delay of a week or two is usually manageable, but extended gaps raise the risk of relapse.
Is risankizumab available as a biosimilar?
No. As of early 2026, risankizumab is still under patent protection and no biosimilar versions are available. This keeps costs high compared to anti-TNF agents like infliximab and adalimumab, which now have multiple biosimilar options.
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For more, see NIH MedlinePlus — dementia.
