A randomized, placebo-controlled experimental medicine study of RIPK1 inhibitor GSK2982772 in patients with moderate to severe rheumatoid arthritis

Background

Receptor-interacting protein kinase 1 (RIPK1) is a key mediator of inflammation through cell death and proinflammatory cytokine production. This multicenter, randomized, double-blind (sponsor-unblinded), placebo-controlled, experimental medicine study evaluated the safety, pharmacokinetics (PK), and preliminary efficacy of GSK2982772, a RIPK1 inhibitor, in moderate to severe rheumatoid arthritis (RA).

Methods

Patients with moderate to severe RA who had received ≥12 weeks’ stable-dose conventional synthetic disease-modifying antirheumatic drug (csDMARD) therapy were randomized (2:1) to GSK2982772 60 mg or placebo orally 2 or 3 times daily for 84 days. Safety, PK, disease activity, joint damage, and pharmacodynamic (PD) biomarkers were assessed at days 43 and 85.

Results

A total of 52 patients were randomized (placebo, 18; GSK2982772, 34). Adverse events (AEs) were reported in 13 (72%) in patients in the placebo group (n = 3 b.i.d; n = 10 t.i.d.) and 20 (61%) in the GSK2982772 group (n = 3 b.i.d; n = 17 t.i.d.). All treatment-related AEs were mild/moderate, except one severe case of alopecia areata at day 49 and retinal vein thrombosis at day 66 (which led to withdrawal from the study) in patients receiving GSK2982772 t.i.d. Disease Activity Score in 28 Joints–C-reactive protein (DAS28-CRP) scores, ACR20/50/70 response, and rates of low disease activity and remission were similar between placebo and GSK2982772 arms.

Conclusions

These results suggest that inhibition of RIPK1 activity at the GSK2982772 exposure levels evaluated do not translate into meaningful clinical improvement of RA.

Trial registration

ClinicalTrials.gov Identifier: NCT02858492. Registered 8 August 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02468-0.

Intranasal GSK2245035, a Toll-like receptor 7 agonist, does not attenuate the allergen-induced asthmatic response in a randomized, double-blind, placebo-controlled experimental medicine study

BACKGROUND

Allergic asthma is a heterogenous disorder predominantly driven by a type 2 inflammatory response to aeroallergens. Therapeutic modulation to rebalance these type 2 responses may offer clinical benefit for allergic respiratory inflammatory diseases, with the potential for disease modification. GSK2245035, a selective toll-like receptor-7 agonist, preferentially stimulates the induction of type 1 interferon alpha, reducing type 2 responses.

OBJECTIVE

This study investigated whether intranasal GSK2245035 reduced allergen-induced bronchial reactivity in mild allergic asthma.

METHODS

This double-blind, placebo-controlled, parallel-group Phase IIa trial randomized (1:1) participants with mild allergic asthma to intranasal GSK2245035 20 ng or placebo once weekly for 8 weeks; follow-up was conducted 1, 4, and 12 weeks after treatment. Allergen-induced late asthmatic response 1 week after treatment was measured as minimum and weighted mean forced expiratory volume in 1 second (FEV1) 4-10 hours following bronchial allergen challenge (primary endpoint). Pharmacodynamic and allergic biomarkers, and adverse events, were assessed. A Bayesian analysis framework was used; a posterior probability >0.7 denoted primary endpoint success.

RESULTS

Thirty-six participants were randomized (GSK2245035, n = 22; placebo, n = 14). The percentage attenuation in late asthmatic response was -4.6% (posterior probability: 0.385) and -10.5% (posterior probability: 0.303) for minimum and weighted mean FEV1, respectively. Type 2 responses were confirmed by changes in lung function, eosinophils (blood and sputum), interleukin-5 (sputum) and fractional exhaled nitric oxide biomarkers pre- and post-bronchial allergen challenge. However, no treatment effect was observed. Adverse events were reported by 10/14 (71%) and 21/22 (95%) participants in the placebo and GSK2245035 groups, respectively; headache was the most common.

CONCLUSIONS AND CLINICAL RELEVANCE

Although target engagement was observed, weekly intranasal GSK2245035 20 ng for 8 weeks did not substantially attenuate the late asthmatic response in participants with mild allergic asthma. Overall, treatment was well tolerated.

Expression of the duffy antigen/receptor for chemokines (DARC) by the inflamed synovial endothelium

The expression of chemokine binding sites on the endothelial cells of venules in inflamed synovia was examined and whether the Duffy antigen/receptor for chemokines (DARC) was involved. In situ binding assays were performed to determine the expression of chemokine binding sites from rheumatoid (n = 10) and non-rheumatoid (n = 10) synovia. The expression of DARC protein and mRNA was examined by immunohistochemistry and northern blotting. The involvement of DARC in chemokine binding was studied by incubating sections with blocking antibodies to DARC (Fy3 and 6), to find out if these reduced 125I-IL-8 binding. Binding of radiolabelled chemokines IL-8, RANTES, MCP-1, but not MIP-1alpha, was found on venular endothelial cells in inflamed synovia from both rheumatoid and non-rheumatoid patients. Excess homologous unlabelled chemokine displaced binding and excess unlabelled RANTES could displace radiolabelled IL-8 binding. DARC protein expression was demonstrated on venular endothelial cells in all samples and DARC mRNA could be detected in extracts from synovia. There was downregulation of DARC protein and mRNA in rheumatoid samples. Binding of IL-8 to both rheumatoid and non-rheumatoid synovia was significantly reduced in the presence of anti-DARC Fy3 and Fy6 monoclonal antibodies. These findings show the expression of a multispecific chemokine binding site on the inflamed synovial endothelium, with evidence for involvement of DARC. This suggests a potential role for DARC in the inflammatory processes involved in synovitis.