Introduction

Current treatment options for IBD are limited by low clinical remission rates and loss of response. Most therapies target single pathogenic pathways and while combinations of biologics targeting different pathogenic cytokines can increase clinical remission rates, dosing schedules are inconvenient. JAK inhibitors, target multiple cytokine pathways, but are limited by safety concerns.
Salt-inducible kinases (SIKs) are a subfamily of serine/threonine kinases in the AMP-activated protein kinase (AMPK) family and act as key regulators of immune cell signaling. SIK inhibitors have been shown to target multiple cytokine pathways.
Three SIK isoforms exist: SIK1, SIK2 and SIK3. SIK inhibitors targeting multiple isoforms have been investigated in clinical trials. Although there have been signals of activity in patients with ulcerative colitis and psoriasis, limited efficacy and safety concerns related to SIK1 and 2 inhibition have hampered their development.

Aims & Methods

We performed structure based drug design to identify highly potent and selective SIK3 inhibitors that could offerbest in class efficacy and safety for the treatment of various auto-immune diseases. Our effort led to to the discovery of 100s of compounds spanning SIK3 binding sites. Compounds were tested in protein and cell-based assays to evaluate potency and selectivity against SIK3 and in a phenotypic human whole blood TNFα assay. Lead optimization involving rigorous testing in safety and pharmacology panels, resulted in the selection of lead candidates that were tested in a variety of translational models to identify the most efficacious compounds. Human PK predictions were performed using non-clinical in vivo PK assessments and allometric scaling leading to the selection of the drug candidate, which entered GLP toxicology studies.

Results

O3R-5671 is a highly potent and specific SIK3 inhibitor with sub-nanomolar potency for SIK3 and low activity against SIK1 and 2 and over all human kinases. It demonstrated potent activity in a panel of human primary phenotypic cell assays inhibiting TNFα, IL-12, and IL-23 release in LPS-stimulated myeloid cells, and inhibiting TNFa release in LPS-stimulated human whole blood. O3R-5671 also inhibited activation of TCR-stimulated human primary T cells and induced IL-10 secretion from myeloid cells.
In vivo, O3R-5671 demonstrated dose-dependent activity in a mouse LPS challenge model, dose-dependent efficacy in two distinct mouse models of IBD, and dose-dependent efficacy in mouse models of IL-23-induced psoriasis and psoriatic arthritis. Cross-species PK and allometric scaling were used to predict O3R-5671’s human PK profile- which is expected to be conducive to potent SIK3 inhibition and clinical efficacy in patients with IBD.
O3R-5671 demonstrated a highly attractive profile in ADME and in vitro safety panels. Six-week GLP toxicity studies in rats and dogs established no observed adverse effect levels (NOAELs) which support dosing in humans with doses that are predicted to be pharmacologically active with a large safety margin.

Conclusion

O3R-5671 is a highly specific and potent SIK3 inhibitor that is predicted to have a flat PK profile in humans. These properties should allow O3R-5671 to apply strong drug pressure on SIK3 while sparing SIK1 and 2. This is expected to result in the inhibition of multiple pathogenic cytokines including TNFa and IL-23, both of which have been validated as IBD targets. A clinical trial is ongoing to establish the safety and PK profile of O3R-5671 and understand its effect on pharmacodynamic biomarkers.

Disclosure

All authors were employed by Galapagos who discovered O3R-5671 or Novalix, a CRO that was employed by Galapagos. Some authors are employed by Onco3R therapeutics, who are currently developing O3R-5671

Introduction

Immune checkpoint inhibitors (ICIs) have marked a breakthrough in the management of a wide range of cancer types, leading to increased overall survival. However, this treatment is frequently associated with the onset of various immune-related adverse events (irAEs), including ICI-related diarrhea and colitis.¹ Current recommendations for patients with diarrhea or colitis grade 2 or higher (graded via CTCAE)² include the discontinuation of ICI and administration of immune suppressants (e.g. steroids or biologics), which may lead to worse outcomes in these patients.³ Therefore, alternative therapeutic strategies to manage irAEs are needed. The gut microbiota plays a pivotal role in the onset of gastrointestinal irAEs, but the role of its therapeutic modulation on these disorders is mostly unknown. ^4,5

Aims & Methods

Our aim was to evaluate the efficacy and safety of therapeutic microbiome modulation for gastrointestinal irAEs in cancer patients. We enrolled cancer patients affected by ICI-related diarrhea/colitis referred to our Microbiome Clinic from January 2023 to March 2025. After clinical evaluation, patients were stratified according to severity of diarrhea (graded via CTCAE)² and then received a microbiome-modulating therapy. Patients were followed-up for at least 8 week after the initiation of therapy. We collected data about patient demographics (age and gender), patient’s overall health status as assessed by the the Charlson Comorbidity Index (CCI)⁶, type of cancer, oncological therapy and its suspension, time in weeks from initiation of cancer therapy to onset of diarrhea, severity of diarrhea (graded via CTCAE)², time in weeks until resolution of diarrhea and resumption of oncological therapy

Results

We enrolled 42 patients in the study period (8 males, 34 females, mean age 58,3 years-old, mean CCI-index 5.8). All patients were treated with ICI (Pembrolizumab: n=25 , Dostarlimab: n=4, Nivolumab: n=4; Atezolizumab: n=3; Novulumab and Ipilumab: n=2, Cemiplimab: n=2; Mogamulizumab: n=1; Pertuzumab: n=1). Ten patients experienced G1 diarrhea (23,8%), 16 (38,1) G2, 15 (35,7%) G3 and one G4 (2,4%). As indicated by current European Guidelines³, 30 patients (71,4%) had to interrupt ICI due to diarrhea. Multi-strain probiotics were administered to 27 (64.3% ) patients, rifaximin to 22 (52,4%). Overall, 21 patients (50%) needed therapy with systemic steroids. Seven patients who experienced ICI-related colitis refractory to steroids and biologics were successfully treated with FMT. Twenty-eight patients (66.7% ) had a resolution of the diarrhea (G0) and 11 patients (26.2%) had diarrhea G1 at a mean time of 8 weeks. Upon resolution of diarrhea, nine of the 30 patients who had interrupted ICI (30%) were able to resume the treatment. None of the patients experienced any adverse event related to gut microbiota modulation as defined by CTCAE².

Conclusion

Therapeutic modulation of gut microbiota appears to be a promising safe and effective approach for treating ICI-related diarrhea and colitis. However, these preliminary findings need confirmation through more consolidated and well-designed studies.

References

1. Dougan M, Wang Y, Rubio-Tapia A, Lim JK. AGA Clinical Practice Update on Diagnosis and Management of Immune Checkpoint Inhibitor Colitis and Hepatitis: Expert Review. Gastroenterology. 2021;160(4):1384-1393. doi:10.1053/j.gastro.2020.08.063
2. Freites-Martinez A, Santana N, Arias-Santiago S, Viera A. Using the Common Terminology Criteria for Adverse Events (CTCAE - Version 5.0) to Evaluate the Severity of Adverse Events of Anticancer Therapies. Actas Dermosifiliogr. 2021;112(1):90-92. doi:10.1016/j.ad.2019.05.009
3. Haanen J, Obeid M, Spain L, et al. Management of toxicities from immunotherapy: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol. 2022;33(12):1217-1238. doi:10.1016/j.annonc.2022.10.001
4. Wang Y, Wiesnoski DH, Helmink BA, et al. Fecal microbiota transplantation for refractory immune checkpoint inhibitor-associated colitis. Nat Med. 2018;24(12):1804-1808. doi:10.1038/s41591-018-0238-9
5. Wang T, Zheng N, Luo Q, et al. Probiotics Lactobacillus reuteri Abrogates Immune Checkpoint Blockade-Associated Colitis by Inhibiting Group 3 Innate Lymphoid Cells. Front Immunol. 2019;10. doi:10.3389/fimmu.2019.01235
6. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. J Chronic Dis. 1987;40(5):373-383. doi:10.1016/0021-9681(87)90171-8

Disclosure

G.I. has received personal fees for acting as speaker for Biocodex, Danone, Sofar, Malesci, Metagenics and Tillotts Pharma, and for acting as consultant and/or advisor for Ferring Therapeutics, Giuliani, Malesci and Tillotts Pharma. A.G. reports personal fees for consultancy from Eisai Srl, 3PSolutions, Real Time Meeting, Fondazione Istituto Danone, SinergieSrl, Board MRGE and Sanofi SpA personal fees for acting as a speaker for Takeda SpA, AbbVie and Sandoz SpA and personal fees for acting on advisory boards for VSL3 and Eisai. G.C. has received personal fees for acting as advisor for Ferring Therapeutics. All other authors have no conflicts of interest to disclose.

Introduction

Genome-wide association studies (GWAS) have identified more than 250 risk variants linked to inflammatory bowel disease (IBD). Most genetic variants increase the risk of disease onset, and their impact on clinical presentation is limited.^1,2,3 Variants in NOD2 and IL23R not only modulate the risk of disease onset, but also influence disease behaviour and localisation. Their role in predicting treatment response remains unclear.^3,4
A variant in an intron of TNRC18 (rs7486781, allele frequency 3.6%) was recently identified as having a strong risk-increasing effect (OR 3.2, p=2.4x10-61) for IBD in the FinnGen biobank study. The same allele was also associated with a risk for ankylosing spondylitis (AS), uveitis and psoriasis.⁵ The functional effect of rs7486781 is not yet fully established.⁶

Aims & Methods

The FinnGen biobank study includes the genotype data of 520 000 individuals and their longitudinal register data from national health registers, including 11 298 individuals with verified diagnosis for IBD. The data also include drug purchases, procedure codes and laboratory measurements of the individuals.
Our aim was to study the impact of the TNRC18-variant on IBD phenotype, particularly disease behavior. We assessed established aspects of disease severity⁷: use of immunosuppressants and advanced therapies, necessity to switch medications, frequent use of corticosteroids and risk of procedures. We also evaluated the presence of extraintestinal manifestations (EIM) and other disease complications.

Results

Regarding disease severity, the use of therapies beyond 5-ASA was more common among variant carriers; the use of thiopurines and other immunosuppressants (OR 1.21-1.27, p-values 1.35x10^-5 - 0.00849), ustekinumab and other IL-inhibitors (OR 1.46-1.48, p-values 0.00324 - 0.00286) and TNF-α-inhibitors (OR 1.26, p=0.00753) was more frequent.
In addition, perianal and anal canal operations were more prevalent with TNRC18 variant carriers (OR 2.44, p=1.41x10^-4), indicating perianal disease.
Assessing EIM, we observed that diagnoses for AS and uveitis (OR 1.62-1.67, p=1.3x10^-5 - 1.55x10^-4) were more frequent within IBD in patients with rs7486781.
Interestingly, a reduced risk of primary sclerosing cholangitis (PSC) was implicated by lower number of cholangitis (K83.0) diagnoses (OR 0.617, p=0.00221) and fewer purchases of ursodeoxycholic acid (OR 0.55, p=2.83x10^-5), in addition to lower levels of ALP (mean 75 vs 82, p=0.00296), IgG4 (mean 0.45 g/l vs 0.81 g/l, p=4.81x10^-5) and IgM (0.12 vs 0.15, p=0.00115) among variant carriers. All events survived the false discovery rate–adjusted p threshold of 0.05.
Our results also suggest that the cumulative risk for IBD related procedures⁸ (patients with procedures n=2209) from diagnosis and birth were elevated in TNRC18 variant carriers (HR=1.12 and HR=1.14, p=0.050 and p=0.023, assuming additive effect) using a Cox regression model.
Finally, our results in ulcerative colitis indicate that TNRC18 variant carriers are at higher risk of transitioning from 5-ASA/immunomodulators to biologics/JAK-inhibitors (HR=1.38, p=0.016). Variant carriers receiving immunomodulators or advanced therapies were not, however, in increased risk of colectomy (HR~0.97-1.34, p~0.86-0.37).

Conclusion

TNRC18 variant was associated with greater risk of operative treatment, the need of more advanced medication and perianal disease. AS and uveitis were more common EIMs, but PSC appeared less infrequent. Our preliminary results indicate that TNRC18 variant carriers might benefit from early intervention with immunomodulators or advanced therapies.

References

1. Chang, J. T. Pathophysiology of Inflammatory Bowel Diseases. N Engl J Med 383, 2652–2664 (2020).

2. Cleynen, I. et al. Inherited determinants of Crohn’s disease and ulcerative colitis phenotypes: a genetic association study. Lancet 387, 156–167 (2016).

3. Atreya, R. & Neurath, M. F. Biomarkers for Personalizing IBD Therapy: The Quest Continues. Clin Gastroenterol Hepatol 22, 1353–1364 (2024).

4. Kayali, S. et al. NOD2 and Crohn’s Disease Clinical Practice: From Epidemiology to Diagnosis and Therapy, Rewired. Inflamm Bowel Dis 31, 552–562 (2025).

5. Kurki, M. I. et al. FinnGen provides genetic insights from a well-phenotyped isolated population. Nature 613, 508–518 (2023).

6. Rahimov, F. et al. A genome-wide CRISPR screen supported by human genetics identifies the TNRC18 gene locus as a novel regulator of inflammatory signaling. bioRxiv 2023.10.04.560902 (2023) doi:10.1101/2023.10.04.560902.

7. Swaminathan, A. et al. The Disease Severity Index for Inflammatory Bowel Disease Is a Valid Instrument that Predicts Complicated Disease. Inflamm Bowel Dis 30, 2064–2075 (2024).

Disclosure

Anna Aarni: Speaker fee from Abbvie, Clinic visit: travelling expenses from Tillots Pharma

Pauliina Molander: Speaker, consultancy and advisory board member fees from Abbvie, Johnson & Johnson, Lilly, Pfizer and Takeda. Clinic visit: traveling expenses from Tillots Pharma

Jukka Koskela: Pfizer-FinnGen genetic advisory board, traveling, clinic and congress visits: FinnGen partners, Tillots Pharma, Takeda, consulting: Pfizer