Primary Hypertrophic Osteoarthropathy With SLCO2A1 Mutation in a Chinese Patient Successfully Treated With Etoricoxib

Biologics for inherited disorders of keratinisation: A systematic review

BACKGROUND/OBJECTIVES

Recent literature highlights the potential of biologics in the management of inherited disorders of keratinisation. In this study, we conducted a systematic review of existing literature on treatment outcomes of inherited keratinisation disorders treated with biologics.

METHODS

Eligible records were retrieved through searches of the electronic databases MEDLINE, Embase, PubMed and Scopus. Databases were searched from inception to July 2023 for eligible records. A snowballing method was employed to search the references of the retrieved records for the identification of potentially relevant articles.

RESULTS

One hundred and four eligible studies consisting of a total of 166 patients with an inherited disorder of keratinisation were included. Patients had a median age of 19 years (range: 0.5 to 70 years). The most common disorders were Netherton syndrome (n = 63; 38%), autosomal recessive congenital ichthyoses (n = 27; 16%), CARD14-associated papulosquamous eruptions (n = 17; 10%) and familial pityriasis rubra pilaris (PRP) (n = 15; 9%).Of the 207 times biologics were employed, the three most frequently employed biologics were secukinumab (n = 47; 23%), dupilumab (n = 44; 21%) and ustekinumab (n = 37; 18%). Complete remission was observed in 10 (5%) instances, partial remission in 129 (62%), no or limited response to biologic therapy in 68 (32%) cases, and results are still pending in one case. A total of 33 adverse events were reported.

CONCLUSIONS

Whilst biologics may be considered in cases of inherited keratinisation disorders recalcitrant to standard therapy, definitive conclusions are prohibited by the low-level of evidence and substantial heterogeneity in methodology across the included studies. Establishment of consensus definitions, and randomised clinical trials may help ascertain the efficacy and safety of biologic therapy in this context and establish the best agent and dosing protocol for each disorder.

Etoricoxib as a treatment of choice for patients with SLCO2A1 mutation exhibiting autosomal recessive primary hypertrophic osteoarthropathy: A case report

We reported a 22-year-old Emirati male with autosomal recessive primary hypertrophic osteoarthropathy caused by a possibly pathogenic homozygous non-synonymous variant in the SLCO2A1 gene (NM_005630.3: c.289C>T, p. Arg97Cys) presenting with joint swelling, forehead furrowing, and significant clubbing in all fingers and toes. Currently, no standard treatments are approved for this disease; medical care is palliative and includes non-steroidal anti-inflammatory drugs, corticosteroids, tamoxifen, retinoids, and risedronate. Colchicine may be helpful for the pain due to subperiosteal new bone formation. Our patient was treated with etoricoxib 60 mg once daily and showed a significant clinical improvement at the 6-month mark that was reversed upon the withdrawal of this medication. This case report highlights the importance of placing etoricoxib among first-line therapy recommendations for cases with confirmed primary hypertrophic osteoarthropathy diagnosis. To the best of our knowledge, this is the only case of primary hypertrophic osteoarthropathy from the Middle Eastern population of Arab ethnicity that has responded to non-steroidal anti-inflammatory drug therapy.

Primary hypertrophic osteoarthropathy related gastrointestinal complication has distinctive clinical and pathological characteristics: two cases report and review of the literature

BACKGROUND

Primary hypertrophic osteoarthropathy (PHO) is a rare disease related to HPGD and SLCO2A1 gene mutation. Gastrointestinal involvement of PHO is even rarer with unknown pathogenesis. Clinical features of GI complication in PHO mimics other auto-immune based bowel entities, such as inflammatory bowel diseases and cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). We aimed to analyze the clinical, genetic, radiological and pathological features of Chinese patients with PHO and determine the difference between PHO patients presenting with and without GI involvement.

METHODS

We reported two PHO cases with gastrointestinal involvement and reviewed all the studies of PHO in Chinese population published from January 1, 2000, to April 30, 2018. Clinical and genetic presentations of PHO in Chinese patients were analyzed. We compared the characteristics of those patients with gastrointestinal involvement against those without.

RESULTS

The two patients were both males with complete-form PHO for more than 10 years. GI related symptoms included diarrhea, chronic gastrointestinal hemorrhage, incomplete intestinal obstruction, anemia, and edema, which were unresponsive to etoricoxib treatment. Radiological examinations revealed segmental intestinal stenosis and thickened intestinal wall. Endoscopic findings included multiple ulcers and mucosal inflammation. Both patients had mutations of SLCO2A1 according to sequence analysis. The surgical pathology revealed chronic inflammation involving the intestinal mucosa and submucosa, similar to histological changes in CMUSE. According to the systemic review of 158 Chinese patients with PHO, 17.2% had gastrointestinal involvement, including peptic ulcer, gastric polyps, hypertrophic gastritis, and segmental intestinal stenosis. Patients with gastrointestinal involvement were more likely to have anemia (40.0% vs. 4.5%, P < 0.001), hypoalbuminemia (16.7% vs. 0.9%, P = 0.003), and myelofibrosis (19.0% vs. 0.9%, P = 0.002) than those without. Most patients with gastrointestinal complication had SLCO2A1 mutation (86.7%, 13 /15).

CONCLUSIONS

Digestive tract involvement is uncommon in patients with PHO and often presents with anemia, and hypoalbuminemia resulted from intestinal inflammation. The intestinal pathologic characteristics are distinct from Crohn's disease but similar to CMUSE. Mutations in SLCO2A1 might be the pathogenic cause of GI involvement of PHO. NSAIDs may not be effective for PHO patients with gastrointestinal complications.

Safety and efficacy of cyclooxygenase-2 inhibition for treatment of primary hypertrophic osteoarthropathy: A single-arm intervention trial

Background

Primary hypertrophic osteoarthropathy (PHO) is a rare disease involving joint, bone and skin. Two underlying genes responsible for this disease-hydroxyprostaglandin dehydrogenase (HPGD) and solute carrier organic anion transporter family, member 2A1 (SLCO2A1)-are both associated with aberrant accumulation of prostaglandin E2 (PGE2). Cyclooxygenase-2 (COX-2) is a key enzyme in PGE2 synthesis. This study was intended to evaluate the safety and efficacy of COX-2 inhibitor in the treatment of PHO.

Methods

We recruited patients presenting to Peking Union Medical Hospital between January 2009 and December 2016 who were diagnosed with PHO. Participants were given the COX-2 inhibitor etoricoxib (60 mg once daily) and followed up for 9 months. Gene analysis was performed at baseline. The following data were collected at baseline and during treatment: visual analogue score (VAS), volume of the distal middle finger (VDMF), knee joint circumference (KJC), serum and urinary levels of prostaglandin E2 (PGE2) and PGE metabolite (PGE-M) and serum levels of inflammatory markers.

Results

A total of 27 patients were recruited, including seven patients with PHO type I (PHOAR1) carrying HPGD gene mutations and 20 patients with PHO type II (PHOAR2) carrying SLCO2A1 gene mutations. After treatment with etoricoxib, the majority of patients experienced resolution of symptoms including pachydermia (60.9%), joint swelling (100%), digital clubbing (74.1%) and hyperhidrosis (55.0%). In both the PHO subtypes, serum and urinary levels of PGE2 were elevated at baseline and declined sharply upon treatment. For PHOAR1 patients, serum and urinary PGE-M levels were relatively low and demonstrated minimal response to COX-2 inhibition. Among PHOAR2 patients, mean serum and urinary levels of PGE-M presented at a high level at baseline and were normalized after 3 months of treatment. No severe adverse effects were reported during the study period.

Conclusions

We found COX-2 inhibitor to be safe and effective for the treatment of PHO in our cohort.

The translational potential of this article

The underlying genes responsible for PHO suggest COX inhibitor as potential therapy, and our study demonstrates the efficacy and safety of this treatment.