Meet the Trialist: Dr Jiwon Oh

Medicom Medical Publishers interviewed neurologist Dr Jiwon Oh (St Michael’s Hospital, University of Toronto, Canada), who presented one of the late-breaking abstracts at the ACTRIMS Forum 2025 [1].

Dr Oh, thank you for your time. Reflecting on the recent ACTRIMS meeting, were there any key presentations or discussions that stood out to you?

“ACTRIMS is a fantastic meeting because it is not as overwhelmingly large as some other MS conferences. It also provides a great opportunity for networking and in-depth discussions. Around ACTRIMS, various affiliated meetings also take place. I am involved in the North American Imaging in MS Cooperative, and we hosted a full-day workshop on spinal cord imaging in MS the day before the conference officially started.”

“We dedicated an entire workshop to spinal cord imaging in MS, which was a great opportunity to focus on an area we often do not have the luxury to explore in depth. Additionally, ACTRIMS offers numerous educational symposia, including a major resident summit, where neurology residents considering a career in MS can engage with faculty members. I participated in several faculty panels during this educational day. This type of meeting fosters opportunities for clinicians and scientists at all levels to interact, learn, and establish long-term professional relationships.”

From a research perspective, were there any particularly interesting findings presented at the conference?

“There were several notable presentations. Of course, I am biased because I was involved in the late-breaking session. I presented data on paramagnetic rim lesions (PRLs), which are an imaging marker of chronic active lesions [1]. This was the first time PRLs were systematically evaluated in a phase 3 clinical trial.”

“Our subgroup analysis found that individuals with higher numbers of PRLs at baseline had a significantly increased likelihood of disease progression over the 2-to-3-year duration of the trial. While we have had cross-sectional data suggesting this association, confirming it within a clinical trial setting is crucial. Additionally, we observed that participants with a higher PRL burden experienced greater treatment effects when treated with tolebrutinib.”

“This is an exciting finding, albeit with the usual caveats of a post hoc subgroup analysis. However, it represents the first time this concept has been demonstrated in a clinical trial setting, with potential implications for future trial design.”

Were there any other findings at ACTRIMS that caught your attention?

“Yes, one presentation that stood out was by Dr Michael Kornberg (Johns Hopkins University, Baltimore, MD, USA), who explored the impact of a ketogenic diet on immune markers over 6 months [2]. Diet is a frequent topic of interest among MS patients, yet our guidance is often limited. We generally recommend a Mediterranean diet because it benefits heart and brain health, but we lack robust evidence specifically for MS.”

“Dr Kornberg’s findings demonstrated clear immune profile changes over 6 months in individuals following a ketogenic diet. Although these are early-stage results, they suggest potential clinical relevance, making this an area worth following closely.”

Turning to smouldering MS, what are the current treatment options, and how important is early intervention?

“Smouldering MS is a key area of focus in the field. We are beginning to appreciate that this phenomenon is becoming more evident, in part, due to the effectiveness of high-efficacy treatments. These therapies successfully suppress relapses and MRI activity, meaning that people do not develop new or contrast-enhancing lesions, yet some patients still develop slowly progressive symptoms over time.”

“We are gaining insight into the pathophysiological mechanisms underlying smouldering MS, but current therapies do not effectively target these processes. Some treatments, such as ocrelizumab and ofatumumab, have demonstrated a modest impact on progression independent of relapse activity (PIRA), which is one clinical measure thought to reflect smouldering disease. Post hoc analyses suggest that these therapies offer a greater effect on PIRA than their comparators.”

“However, if you ask whether we have a drug that definitively alters the trajectory of smouldering MS, the answer is no. This is precisely why there is significant interest in Bruton’s tyrosine kinase (BTK) inhibitors and other emerging therapies. While some existing treatments may have a modest effect, the need for novel therapeutics targeting smouldering MS remains critical.”

Should trigeminal neuralgia be considered a diagnostic symptom of MS?

“Trigeminal neuralgia (TN) is notably more common in MS than in the general population, but it also occurs spontaneously. Could TN be a manifestation of smouldering MS? Possibly, any MS symptom could be.”

“The distinction between smouldering MS and a clinical relapse lies in the onset and duration of symptoms. Smouldering MS tends to present with chronic symptoms that gradually worsen, whereas relapses emerge acutely and may resolve over time. If TN were part of smouldering MS, one might expect its frequency and severity to increase progressively.”

“However, there is an ongoing debate within the field regarding whether TN should be classified as a presenting symptom of MS. A colleague of mine, Dr Andy Solomon (The University of Vermont, Burlington, VT, USA), who specialises in MS diagnosis, contributed to a paper we published in Toronto addressing this exact question [3]. The current diagnostic criteria for relapsing MS include symptoms indicative of optic neuritis, partial myelitis, or infratentorial syndromes—but not TN, despite its high prevalence in MS. This raises the question of whether it should be included in future diagnostic criteria.”

Looking ahead, what developments in MS research are you most excited about?

“The upcoming results from BTK inhibitor clinical trials will be closely watched. In the next 12 to 18 months, we expect to hear more about fenebrutinib’s phase 3 programme and the results of the tolebrutinib primary progressive MS clinical trial.”

“While there was disappointment regarding the evobrutinib trial, tolebrutinib has shown intriguing results, particularly in non-relapsing secondary progressive MS. Even in the GEMINI I (NCT04410978) and GEMINI II (NCT04410991) clinical trials, while relapse rates were not significantly different from teriflunomide, there was a clear difference in disability progression, which is compelling [4]. Given what we understand about smouldering MS, and that we know tolebrutinib has CNS penetrance at bioactive concentrations, the field remains interested in tolebrutinib and other BTK inhibitors, and fenebrutinib has properties that suggest it may offer clinical benefit.”

“Additionally, the phase 2 data for frexalimab were promising, and we anticipate phase 3 results in the next 2–2.5 years. There is also increasing interest in how fluid and imaging biomarkers can be integrated into clinical practice and trial design to assess progression and treatment response better. These advancements can potentially reshape how we approach MS treatment and monitoring.”

1. Oh J, et al. Paramagnetic rim lesions as a prognostic and predictive biomarker in the tolebrutinib phase 3 trials for disability outcomes. LB1.1, ACTRIMS 2025, 27 February–01 March 2025, West Palm Beach, FL, USA.
2. Kornberg M, et al. A six-month ketogenic diet alters the immune and metabolic landscape in multiple sclerosis. LB1.2, ACTRIMS 2025, 27 February–01 March 2025, West Palm Beach, FL, USA.
3. Laakso SM, et al. Mult Scler. 2024 Dec 27:13524585241309257.
4. Oh J, et al. Abstract O135, ECTRIMS 2024, 18–20 September, Copenhagen, Denmark.

The views and opinions of the interviewee are their own, and do not necessarily represent the stance or responsibility of the Editor or the Publisher. The content is provided for informational purposes only and should not be considered official editorial content, endorsement, or medical advice.

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Posted on 5 March 202525 March 2025