Canakinumab treatment real world evidence in 3 monogenic periodic fever syndromes in 2009-2022: an interim analysis using the French JIR cohort database.

BACKGROUND: Our study aimed to provide real-world evidence on the treatment patterns, effectiveness and safety of canakinumab in France in Familial Mediterranean Fever (FMF), Mevalonate Kinase Deficiency (MKD), and Tumor necrosis factor Receptor Associated Periodic Syndrome (TRAPS). METHODS: This study used the JIR cohort, a multicentre international registry created in 2013 to collect data on patients with juvenile inflammatory rheumatic diseases. French patients diagnosed with FMF, MKD or TRAPS and treated with canakinumab were included in this study. RESULTS: 31 FMF, 26 MKD and 7 TRAPS patients received canakinumab during the study period. Most of them initiated canakinumab at the recommended dose of 2 mg/kg or 150 mg, but less than half of FMF and MKD patients initiated it at the recommended frequency (every 4 weeks). Two years after initiation, the rate of patients still on treatment was 78.1% in FMF, 73.7% in MKD, and 85.7% in TRAPS patients. While the dose per injection remained globally the same over the course of the treatment, some adjustments of the dose intervals were observed. Six patients had a severe adverse event reported. Of those, three were possibly related to canakinumab. CONCLUSION: This interim analysis showed a good maintenance of canakinumab treatment 2 years after initiation and confirmed its safety profile in real-life practice in France in patients diagnosed with FMF, MKD and TRAPS. The high variety of dose and interval combinations observed in canakinumab treated patients let suppose that physicians adapt the posology to individual situations rather than a fixed treatment plan.

Long-term safety and effectiveness of canakinumab in patients with monogenic autoinflammatory diseases: results from the interim analysis of the RELIANCE registry.

OBJECTIVE: Interim analysis of the RELIANCE registry, an on-going, non-interventional, open-label, multicentre, prospective study evaluating the long-term safety, dosing regimens and effectiveness of canakinumab in patients with cryopyrin-associated periodic syndromes (CAPS), familial Mediterranean fever (FMF), tumour-necrosis factor receptor-associated periodic syndrome (TRAPS) or mevalonate-kinase deficiency (MKD)/hyperimmunoglobulin-D syndrome (HIDS). METHODS: From September 2017 for patients with CAPS, and June 2018 for patients with FMF, TRAPS or MKD/HIDS, the registry enrolled paediatric (aged ≥2 years) and adult patients (aged ≥18 years) receiving canakinumab as part of their routine medical care. Safety, canakinumab dose, disease activity and quality of life outcome measures were evaluated at baseline and every 6 months until end of study visit. RESULTS: At the analysis cut-off date (December 2020), 168 patients (91 CAPS, 54 FMF, 16 TRAPS and 7 MKD/HIDS) were enrolled. 85 (50.9%) patients were female and 72 (43.1%) were children (<18 years). The median patient age was 20.0 years (range 2.0-79.0 years). In the CAPS cohort, serious infections and serious adverse drug-reactions were more common in patients receiving higher than the recommended starting dose (SD) of canakinumab. A trend to receive >SD of canakinumab was observed in the pooled population. The majority of patients were reported as having either absent or mild/moderate disease activity (physician's global assessment) from baseline to Month 30, with a stable proportion of patients (~70%) in remission under canakinumab treatment. Patient-reported disease activity (Visual Analogue Scale (VAS), Autoinflammatory Disease Activity Index), fatigue (VAS); markers of inflammation (C-reactive protein, serum amyloid A and erythrocyte sedimentation rate) remained well-controlled throughout. CONCLUSION: Data from this analysis confirm the long-term safety and effectiveness of canakinumab for the treatment of CAPS, FMF, TRAPS and MKD/HIDS.

Tocilizumab for treating mevalonate kinase deficiency and TNF receptor-associated periodic syndrome: a case series and literature review.

BACKGROUND: Mevalonate kinase deficiency (MKD) and TNF receptor-associated periodic syndrome (TRAPS) are categorized as systemic autoinflammatory diseases (SAIDs), which are rare diseases characterized by early onset, severe conditions, and challenging diagnosis and treatment. Although different SAIDs have varying standard treatments, some SAIDs are poorly controlled after routine treatment, seriously affecting the growth and development of children and their quality of life. This study aims to provide more treatment strategies for SAIDs. CASE PRESENTATION: We present two Chinese patients with MKD and TRAPS who were resistant to TNF- (tumor necrosis factor-) α blockade. After using etanercept, baricitinib, and glucocorticoid, patients with MKD and TRAPS still had periodic fever and rash. Due to the unavailability of IL-1 antagonists in the Chinese Mainland, we started administering intravenous tocilizumab (TCZ) at a dosage of 240 mg every three weeks. They had not experienced fever or rash after receiving one or two doses of TCZ. Before treatment with TCZ in the MKD patient, white blood cell (WBC) count, and TNF-α level were normal, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) increased significantly, and IL-6 increased slightly. After treatment with TCZ, ESR and CRP levels returned to normal; however, IL-6 increased occasionally. In the TRAPS patient, ESR, CRP, WBC, IL-6, and TNF-α levels were increased significantly. After TCZ treatment, ESR, CRP, WBC, IL-6, and TNF-α levels returned to normal. The two patients were treated with TCZ for more than six months and achieved clinical and serological remission. Furthermore, they had no adverse reactions after injection of TCZ. CONCLUSION: In the absence of IL-1 antagonists in mainland China, tocilizumab emerges as an alternative drug in SAIDs that are resistant to TNF-α blockade.

A case of mevalonate kinase deficiency, neonatal Sweet syndrome, and inflammatory bowel disease.

Mevalonate kinase deficiency is a group of rare metabolic autoinflammatory disorders that present with recurrent fevers, abdominal pain, arthralgias, adenopathy, and a variety of cutaneous manifestations. The skin findings may mimic cellulitis, erythema elevatum diutinum, IgA vasculitis, and Sweet syndrome, and there is often a morbilliform or urticarial rash and aphthous stomatitis. Mevalonate kinase deficiency is one of the identified monogenic variants that can cause very early onset inflammatory bowel disease (IBD). We present a rare case of a patient with mevalonate kinase deficiency, neonatal Sweet syndrome, and infantile-onset IBD, who has been successfully treated with canakinumab therapy.

Long-term efficacy of canakinumab in hyperimmunoglobulin D syndrome.

Hyperimmunoglobulin D syndrome (HIDS) is a rare autoinflammatory disorder with autosomal recessive inheritance. It is caused by specific mutations in the mevalonate kinase gene (MVK). No treatment specific to HIDS has been approved to date; however, nonsteroidal anti-inflammatory drugs, steroids, colchicine, tumor necrosis factor-α inhibitors, and anti-interleukin-1 treatments are used, based on case reports and observational studies. Herein, we report a case with recurrent fever and arthritis attacks who did not respond to anakinra and was successfully treated with canakinumab. Long-term remission was achieved without any side effects with 300 mg canakinumab treatment every 4 weeks for 5 years.

Identification of FDA-approved drugs that increase mevalonate kinase in hyper IgD syndrome.

Mevalonate kinase deficiency (MKD) is an autoinflammatory metabolic disorder caused by bi-allelic loss-of-function variants in the MVK gene, resulting in decreased activity of the encoded mevalonate kinase (MK). Clinical presentation ranges from the severe early-lethal mevalonic aciduria to the milder hyper-IgD syndrome (MKD-HIDS), and is in the majority of patients associated with recurrent inflammatory episodes with often unclear cause. Previous studies with MKD-HIDS patient cells indicated that increased temperature, as caused by fever during an inflammatory episode, lowers the residual MK activity, which causes a temporary shortage of non-sterol isoprenoids that promotes the further development of inflammation. Because an increase of the residual MK activity is expected to make MKD-HIDS patients less sensitive to developing inflammatory episodes, we established a cell-based screen that can be used to identify compounds and/or therapeutic targets that promote this increase. Using a reporter HeLa cell line that stably expresses the most common MKD-HIDS variant, MK-V377I, C-terminally tagged with bioluminescent NanoLuc luciferase (nLuc), we screened the Prestwick Chemical Library®, which includes 1280 FDA-approved compounds. Multiple compounds increased MK-V377I-nLuc bioluminescence, including steroids (i.e., glucocorticoids, estrogens, and progestogens), statins and antineoplastic drugs. The glucocorticoids increased MK-V377I-nLuc bioluminescence through glucocorticoid receptor signaling. Subsequent studies in MKD-HIDS patient cells showed that the potent glucocorticoid clobetasol propionate increases gene transcription of MVK and other genes regulated by the transcription factor sterol regulatory element-binding protein 2 (SREBP-2). Our results suggest that increasing the flux through the isoprenoid biosynthesis pathway by targeting the glucocorticoid receptor or SREBP-2 could be a potential therapeutic strategy in MKD-HIDS.

Real-world safety and effectiveness of canakinumab in patients with tumour necrosis factor receptor-associated periodic syndrome or hyperimmunoglobulinaemia D syndrome: Interim results from post-marketing surveillance in Japan.

OBJECTIVES: To assess the real-world safety and effectiveness of canakinumab in patients in Japan with tumour necrosis factor receptor-associated periodic syndrome (TRAPS) or mevalonate kinase deficiency/hyperimmunoglobulinaemia D with periodic fever syndrome (MKD/HIDS). METHODS: All patients with TRAPS or MKD/HIDS who received canakinumab following drug approval in Japan were registered in a post-marketing all-patient surveillance with a 2-year observation period. Herein, the interim results are reported. RESULTS: Fifteen patients with TRAPS and seven with MKD/HIDS were included in the safety and effectiveness analysis set. Adverse drug reactions were reported in 26.67% (n = 4) and 42.86% (n = 3) of TRAPS and MKD/HIDS patients, respectively. Most common adverse drug reactions were upper respiratory tract inflammation (13.33%, n = 2) and pyrexia (42.86%, n = 3) in TRAPS and MKD/HIDS patients, respectively. No serious adverse drug reactions were observed in either TRAPS or MKD/HIDS patients. The proportion of responders was 46.67% and 14.29% in the TRAPS and MKD/HIDS groups, respectively; 72.73% and 66.67% achieved clinical remission, while 90.91% and 66.67% achieved serological remission by Week 4 in the TRAPS and MKD/HIDS groups, respectively. CONCLUSIONS: These interim results provide the first evidence of the real-world effectiveness of canakinumab in patients with TRAPS or MKD/HIDS in Japan. No new safety concerns were identified.

Recurrent macrophage activation syndrome due to hyperimmunoglobulin D syndrome: a case-based review.

Hyperimmunoglobulin D syndrome (HIDS) is a hereditary autoinflammatory disease characterized by recurrent inflammatory attacks with fever, abdominal pain, lymphadenopathy, aphthous stomatitis, and skin lesions. There are few reports on HIDS patients complicated with macrophage activation syndrome (MAS); however, to our knowledge, there is no case of HIDS with recurrent MAS attacks. We report two pediatric patients initially diagnosed as Kawasaki disease and systemic juvenile idiopathic arthritis presented with recurrent MAS episodes with prolonged fever, skin rash, hepatosplenomegaly, cervical lymphadenopathy, aphthous stomatitis, headache, pancytopenia, hyperferritinemia, and hypofibrinogenemia, finally diagnosed as HIDS with a documented homozygous MVK gene mutation. This is the first report on recurrent MAS attacks due to HIDS in pediatric patients who were successful treated with corticosteroids and anti-IL-1 therapies. Thus, clinicians should be vigilantly investigated signs of autoinflammatory diseases in patients with recurrent MAS attacks during their disease course, and HIDS should be considered an underlying disease for triggering recurrent MAS attacks. We have also reviewed the current literature regarding HIDS cases complicated with a MAS attack and summarized their demographic, treatment, and outcome characteristics. Key points • Hyperimmunoglobulin D syndrome should be considered in differential diagnosis in patients who experienced recurrent macrophage activation syndrome attacks.

Ischemic stroke is a potential complication of uncontrolled inflammation in mevalonate kinase deficiency - A case report.

OBJECTIVES: Mevalonate kinase deficiency (MKD) is an autosomal recessive autoinflammatory disease characterized by recurrent systemic inflammation attacks. Despite interconnections with inflammation, thrombosis is rare or underreported in MKD. Our goal is to report evidence of uncontrolled inflammation as the cause of ischemic stroke. MATERIALS AND METHODS: Case report. RESULTS: A 39-year-old French-Canadian patient consulted for stroke. He reported a previous diagnosis of familial Mediterranean fever and hospitalizations nearly monthly since birth for recurrent inflammatory attacks despite colchicine prophylaxis. Attacks were triggered by infections or stress, lasted 3-7 days, and included fever up to 41°C, painful lymphadenopathies, abdominal pain, polyarthralgia and maculopapular rash. Stroke culminated his most recent inflammatory attack. Brain MRI confirmed an acute infarct, without chronic ischemic damage. Blood tests documented increased C-reactive protein, amyloid A and immunoglobulin-D. Prothrombotic and autoantibody tests, cervicocephalic CT-angiography, echocardiography, cardiac monitoring, and toxic screen were unremarkable. Infections were excluded. His only sister had similar attacks. In both cases, sequencing of 32 autoinflammatory-associated genes identified two pathogenic mevalonate kinase mutations. Their non-consanguineous parents, half-brother and four children were asymptomatic. Following treatment with anti-interleukin-1beta monoclonal antibodies, he no longer had inflammatory attacks or stroke in >4 years. CONCLUSION: This MKD patient experienced an ischemic stroke during an attack, attributed to uncontrolled inflammation. Investigations excluded other stroke etiologies. Recurrent febrile attacks starting before age 1 and lasting >3 days, gastrointestinal symptoms, painful lymphadenopathies, maculopapular rash, triggers, aphthous stomatitis, non-Mediterranean ancestry, and ineffectiveness of colchicine prophylaxis are consistent with MKD. Anti-interleukin-1 therapy prevents recurrent autoinflammatory attacks.

Increased core body temperature exacerbates defective protein prenylation in mouse models of mevalonate kinase deficiency.

Mevalonate kinase deficiency (MKD) is characterized by recurrent fevers and flares of systemic inflammation, caused by biallelic loss-of-function mutations in MVK. The underlying disease mechanisms and triggers of inflammatory flares are poorly understood because of the lack of in vivo models. We describe genetically modified mice bearing the hypomorphic mutation p.Val377Ile (the commonest variant in patients with MKD) and amorphic, frameshift mutations in Mvk. Compound heterozygous mice recapitulated the characteristic biochemical phenotype of MKD, with increased plasma mevalonic acid and clear buildup of unprenylated GTPases in PBMCs, splenocytes, and bone marrow. The inflammatory response to LPS was enhanced in compound heterozygous mice and treatment with the NLRP3 inflammasome inhibitor MCC950 prevented the elevation of circulating IL-1ß, thus identifying a potential inflammasome target for future therapeutic approaches. Furthermore, lines of mice with a range of deficiencies in mevalonate kinase and abnormal prenylation mirrored the genotype-phenotype relationship in human MKD. Importantly, these mice allowed the determination of a threshold level of residual enzyme activity, below which protein prenylation is impaired. Elevated temperature dramatically but reversibly exacerbated the deficit in the mevalonate pathway and the defective prenylation in vitro and in vivo, highlighting increased body temperature as a likely trigger of inflammatory flares.

Use of the Auto-inflammatory Disease Activity Index to monitor disease activity in patients with colchicine-resistant Familial Mediterranean Fever, Mevalonate Kinase Deficiency, and TRAPS treated with canakinumab.

OBJECTIVES: To evaluate the feasibility of the autoinflammatory disease activity index (AIDAI) as a tool to assess disease activity in patients with hereditary recurrent fever syndromes (HRFs) treated with canakinumab. METHODS: Patients with active colchicine-resistant familial Mediterranean fever (crFMF), mevalonate kinase deficiency (MKD), or tumor necrosis factor receptor-associated periodic syndrome (TRAPS) were enrolled in the phase III CLUSTER study and asked to complete the AIDAI questionnaire daily. All patients included in the analysis were treated with canakinumab, but regimens and periods of treatment varied per study protocol. The AIDAI for each patient was calculated weekly over the first 40 weeks of study, based on the diaries completed over 30 days. Disease-specific cut-off AIDAI values for inactive disease were calculated in a ROC analysis by comparing AIDAI scores with the occurrence of clinically inactive disease, based on the physician global assessments of disease activity and the occurrence of flares. RESULTS: Sixty patients with crFMF, 70 with MKD, and 43 with TRAPS were included in the analysis. Median AIDAI scores were high during the first 4 weeks for the three disease cohorts, and decreased afterwards, with some differences between disease cohorts. AIDAI values of 12.0, 9.6 and 15.5 were obtained as the most optimal thresholds to discriminate patients with inactive disease, with sensitivity and specificity values mostly over 75%. CONCLUSIONS: The AIDAI allows to discriminate between patients with active and inactive HRFs, and can be used in clinical practice to monitor the disease course of patients and the effect of medications.

The 2021 EULAR/American College of Rheumatology Points to Consider for Diagnosis, Management and Monitoring of the Interleukin-1 Mediated Autoinflammatory Diseases: Cryopyrin-Associated Periodic Syndromes, Tumour Necrosis Factor Receptor-Associated Periodic Syndrome, Mevalonate Kinase Deficiency, and Deficiency of the Interleukin-1 Receptor Antagonist.

BACKGROUND: The interleukin-1 (IL-1) mediated systemic autoinflammatory diseases, including the cryopyrin- associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD) and deficiency of the IL-1 receptor antagonist (DIRA), belong to a group of rare immunodysregulatory diseases that primarily present in early childhood with variable multiorgan involvement. When untreated, patients with severe clinical phenotypes have a poor prognosis, and diagnosis and management of these patients can be challenging. However, approved treatments targeting the proinflammatory cytokine IL-1 have been life changing and have significantly improved patient outcomes. OBJECTIVE: To establish evidence-based recommendations for diagnosis, treatment and monitoring of patients with IL-1 mediated autoinflammatory diseases to standardise their management. METHODS: A multinational, multidisciplinary task force consisting of physician experts, including rheumatologists, patients or caregivers and allied healthcare professionals, was established. Evidence synthesis, including systematic literature review and expert consensus (Delphi) via surveys, was conducted. Consensus methodology was used to formulate and vote on statements to guide optimal patient care. RESULTS: The task force devised five overarching principles, 14 statements related to diagnosis, 10 on therapy, and nine focused on long-term monitoring that were evidence and/or consensus-based for patients with IL-1 mediated diseases. An outline was developed for disease-specific monitoring of inflammation-induced organ damage progression and reported treatments of CAPS, TRAPS, MKD and DIRA. CONCLUSION: The 2021 EULAR/American College of Rheumatology points to consider represent state-of-the-art knowledge based on published data and expert opinion to guide diagnostic evaluation, treatment and monitoring of patients with CAPS, TRAPS, MKD and DIRA, and to standardise and improve care, quality of life and disease outcomes.

The 2021 EULAR/American College of Rheumatology points to consider for diagnosis, management and monitoring of the interleukin-1 mediated autoinflammatory diseases: cryopyrin-associated periodic syndromes, tumour necrosis factor receptor-associated periodic syndrome, mevalonate kinase deficiency, and deficiency of the interleukin-1 receptor antagonist.

BACKGROUND: The interleukin-1 (IL-1) mediated systemic autoinflammatory diseases, including the cryopyrin-associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD) and deficiency of the IL-1 receptor antagonist (DIRA), belong to a group of rare immunodysregulatory diseases that primarily present in early childhood with variable multiorgan involvement. When untreated, patients with severe clinical phenotypes have a poor prognosis, and diagnosis and management of these patients can be challenging. However, approved treatments targeting the proinflammatory cytokine IL-1 have been life changing and have significantly improved patient outcomes. OBJECTIVE: To establish evidence-based recommendations for diagnosis, treatment and monitoring of patients with IL-1 mediated autoinflammatory diseases to standardise their management. METHODS: A multinational, multidisciplinary task force consisting of physician experts, including rheumatologists, patients or caregivers and allied healthcare professionals, was established. Evidence synthesis, including systematic literature review and expert consensus (Delphi) via surveys, was conducted. Consensus methodology was used to formulate and vote on statements to guide optimal patient care. RESULTS: The task force devised five overarching principles, 14 statements related to diagnosis, 10 on therapy, and nine focused on long-term monitoring that were evidence and/or consensus-based for patients with IL-1 mediated diseases. An outline was developed for disease-specific monitoring of inflammation-induced organ damage progression and reported treatments of CAPS, TRAPS, MKD and DIRA. CONCLUSION: The 2021 EULAR/American College of Rheumatology points to consider represent state-of-the-art knowledge based on published data and expert opinion to guide diagnostic evaluation, treatment and monitoring of patients with CAPS, TRAPS, MKD and DIRA, and to standardise and improve care, quality of life and disease outcomes.

Current treatment options for monogenic periodic fever syndromes - the role of interleukin 1 inhibitors.

Monogenic periodic fever syndromes are heterogeneous group of autoinflammatory diseases including distinct syndromes, such as cryopyrin-associated periodic syndrome (CAPS), tumor necrosis factor alpha receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency/hyper IgD syndrome (MKD/HIDS), and familial Mediterranean fever (FMF). Individual diseases differ in pathogenesis, clinical manifestations, and severity. However, cytokines from the interleukin 1 (IL-1) family play a key role in all of them. Inhibition of these cytokines, especially IL-1, thus plays a crucial role in their treatment. At present, we have a wide range of drugs that differ in structure, mechanism of action, efficacy, and spectrum of side effects. The most available are anakinra, canakinumab and rilonacept. Moreover, several clinical trials are currently underway with other very promising drugs, such as gevokizumab, tadekinig alfa or tranilast. In the following review, we provide a new perspective on the efficacy and safety of IL-1 inhibitors that have provided the novel results coming from recently published clinical trials.

Uveitis, glaucoma, and cataract with mevalonate kinase deficiency.

We report 7 years of follow-up data on ocular findings in a 2-month-old boy who presented with early-onset bilateral granulomatous panuveitis with subsequent development of secondary glaucoma and total cataract, along with multisystem involvement. He was diagnosed with mevalonate kinase deficiency (MKD), with a homozygous missense variant in exon-6 of the mevalonate kinase (MVK) gene on chromosome-12 that resulted in the substitution of aspartic acid for asparagine at codon 205 (p.Asn205Asp). Despite being managed with topical/systemic steroids and immunosuppression therapy with methotrexate and a short course of adalimumab, the patient continued to develop recurrent episodes of uveitis along with multisystem manifestations. The occurrence of early-onset uveitis is rare, as is the diagnosis of MKD.

Long-term efficacy and safety of canakinumab in patients with mevalonate kinase deficiency: results from the randomised Phase 3 CLUSTER trial.

OBJECTIVES: To evaluate the long-term efficacy and safety of canakinumab in patients with mevalonate kinase deficiency during the open label extension (weeks 41-113) of the randomized controlled CLUSTER trial. METHODS: During a 72-week period, patients received open-label canakinumab 150 or 300 mg, every 4 or 8 weeks. The disease activity was evaluated every 8 weeks using physician global assessment and counting the number of flares. Concentrations of CRP and serum amyloid A protein were measured. The safety was studied by determination and classification of observed adverse events. The safety and efficacy were analysed separately in three subgroups of patients receiving a cumulative dose of less than <35 mg/kg, ≥35 to <70 mg/kg or ≥70 mg/kg. RESULTS: Of the 74 patients who started the CLUSTER study, 66 entered Epoch 4 and 65 completed it. During the 72-week period, 42 (64%) patients experienced no flares, while 13 (20%) had one flare, as compared with a median of 12 flares per year reported at baseline. Low physician global assessment scores were seen at the end of the study for all groups with >90% reporting minimal disease activity or none at all. Median CRP concentrations were consistently equal or lower than 10 mg/l, while median serum amyloid A concentrations remained only slightly above the normal range of 10 mg/l. The study showed no new or unexpected adverse events. CONCLUSION: Canakinumab proved effective to control disease activity and prevent flares in mevalonate kinase deficiency during the 72-week study period. No new safety concerns were reported. TRIAL REGISTRATION: NCT02059291. https://clinicaltrials.gov.

Compromised Protein Prenylation as Pathogenic Mechanism in Mevalonate Kinase Deficiency.

Mevalonate kinase deficiency (MKD) is an autoinflammatory metabolic disorder characterized by life-long recurring episodes of fever and inflammation, often without clear cause. MKD is caused by bi-allelic pathogenic variants in the MVK gene, resulting in a decreased activity of the encoded enzyme mevalonate kinase (MK). MK is an essential enzyme in the isoprenoid biosynthesis pathway, which generates both non-sterol and sterol isoprenoids. The inflammatory symptoms of patients with MKD point to a major role for isoprenoids in the regulation of the innate immune system. In particular a temporary shortage of the non-sterol isoprenoid geranylgeranyl pyrophosphate (GGPP) is increasingly linked with inflammation in MKD. The shortage of GGPP compromises protein prenylation, which is thought to be one of the main causes leading to the inflammatory episodes in MKD. In this review, we discuss current views and the state of knowledge of the pathogenetic mechanisms in MKD, with particular focus on the role of compromised protein prenylation.

Mevalonate Kinase Deficiency: A Cause of Severe Very-Early-Onset Inflammatory Bowel Disease.

Mevalonate kinase deficiency should be considered in patients with severe very-early-onset inflammatory bowel disease (IBD), especially in patients with a history of recurrent or chronic fever, peritoneal adhesions, and atypical IBD pathology. Anti-interleukin-1 therapy may be efficacious in these patients with monogenic very-early-onset IBD.

Reasons for canakinumab initiation among patients with periodic fever syndromes: a retrospective medical chart review from the United States.

BACKGROUND: Although canakinumab has demonstrated efficacy in multiple trials in patients with periodic fever syndromes (PFS), the evidence on initiation of canakinumab among PFS patients in real world setting is not well understood. We aimed to characterize the reasons for canakinumab initiation among patients with PFS, specifically, cryopyrin-associated periodic syndrome (CAPS), hyperimmunoglobulin D syndrome/mevalonate kinase deficiency (HIDS/MKD), TNF receptor-associated periodic syndrome (TRAPS) and familial Mediterranean fever (FMF). METHODS: Physicians retrospectively reviewed the medical charts of PFS patients prescribed canakinumab between 2016 and 2018. Information collected included patient clinical characteristics, reasons for previous treatment discontinuation and canakinumab initiation. The results were summarized for overall patients, and by children (< 18 years) and adults and by subtype of PFS. RESULTS: Fifty-eight physicians in the US (rheumatologists, 44.8 %; allergists/immunologists, 29.3 %; dermatologists, 25.9 %) abstracted information for 147 patients (children, 46.3 %; males, 57.1 %; CAPS, 36.7 %; TRAPS, 26.5 %; FMF, 26.5 %; HIDS/MKD, 6.8 %; Mixed, 3.4 %). Overall, most patients (90.5 %) received treatment directly preceding canakinumab (NSAIDs, 27.8 % [40.0 % in HIDS/MKD]; anakinra, 24.1 % [32.7 % in CAPS]; colchicine, 21.8 % [35.9 % in FMF]), which were discontinued due to lack of efficacy/effectiveness (39.5 %) and availability of a new treatment (36.1 %). The common reasons for canakinumab initiation were physician perceived efficacy/effectiveness (81.0 %; children, 75.0 %; adults, 86.1 %), lack of response to previous treatment (40.8 %; children, 38.2 %; adults, 43.0 %) and favorable safety profile/tolerability (40.1 %; children, 42.6 %; adults, 38.0 %). Within subtypes, efficacy/effectiveness was the most stated reason for canakinumab initiation in HIDS/MKD (90.9 %), lack of response to previous treatment in FMF (52.4 %) and convenience of administration/dosing in CAPS (27.1 %). CONCLUSIONS: This study provided insights into how canakinumab is initiated in US clinical practice among PFS patients, with physician perceived efficacy/effectiveness of canakinumab, lack of response to previous treatment and favorable safety profile/tolerability of canakinumab being the dominant reasons for canakinumab initiation in all patients and in children and adults and PFS subtypes. Notably, the favorable safety profile/tolerability of canakinumab was more often the reason for initiation among children versus adults.