Consensus recommendations on appropriate coagulation tests during emicizumab administration in Saudi Arabia.

INTRODUCTION: Emicizumab is a bispecific monoclonal antibody with the ability to bridge FIXa and FX, mimic FVIII, and restore normal hemostasis in patients with hemophilia A. Moreover, substantial evidence has shown that emicizumab-treated patients do not require monitoring, except before surgery or invasive procedures. However, introducing this novel drug to the market poses some challenges to physicians and clinical laboratories due to its interaction with conventional coagulation tests. METHODS: Given the challenges and laboratory interactions posed by this novel drug, there is an unmet clinical need to develop clear recommendations for emicizumab laboratory monitoring to highlight which laboratory tests should be used, which tests should be avoided, and when these tests should be performed. These expert recommendations are essential to prevent inappropriate testing or misleading interpretations and reduce the extra costs of unnecessary monitoring. RESULTS: A consensus meeting was conducted in December 2019, including top experts on hemophilia from Saudi Arabia, to discuss this issue. CONCLUSION: The experts agreed that, aPTT (activated Partial Thromboplastin Time)-based tests are not suitable for laboratory monitoring patients treated with emicizumab. Only FVIII chromogenic assays based on bovine FIX and FX proteins can be used to measure FVIII levels. They reviewed and recommended the type and time of testing for anti-factor VIII antibodies. Drug levels should be measured using the recommended test only when the anti-drug antibody (ADA) is clinically suspected and after excluding other causes (such as patient non-compliance).

Travel burden and geographic access to health care among children with cancer in Saudi Arabia.

BACKGROUND: Travel burden has a substantial psychosocial impact and financial strain on childhood cancer patients and their families. AIMS: To study the geographic distribution of childhood cancer and assess the travel burden for care in Saudi Arabia. METHODS: This was a cross-sectional multi-institutional study that enrolled 1657 children with cancer who were diagnosed between 2011 and 2014. Cancer type/stage, city/region of residence, and city/region of treating centre were recorded. Travel burden was measured based on a 1-way distance in kilometres from the city centre to the treatment institution. This study was supported by Sanad Children's Cancer Support Association. RESULTS: Diagnosis was leukaemia (45.2%), non-CNS solid tumours (30.2%), lymphoma (12.3%), CNS tumours (11.8%) and histiocytosis (0.5%). Childhood cancer centres were in the same city as where the patients lived in 652 (39.3%) cases, same region but different city in 308 (18.6%), different regions in 613 (37%), and not known in 84 (5.1%). The mean 1-way travel distance for patients who lived in different regions was 790 (range, 116-1542) km. A total of 536 (32%) patients lived ≥ 400 km and 216 (13%) > 1000 km from the treatment centre. Among 642 patients with acute lymphoblastic leukaemia who required 2-3 years of therapy, 197 (31%) lived ≥ 400 km and 94 (15%) >1000 km from the treatment centre. CONCLUSIONS: Nearly two thirds of patients with childhood cancer lived in different cities than the treatment centres, including one third of patients who lived ≥ 400 km away. There is a need to develop strategies to improve access to childhood cancer care.

Frequency of pathogenic/likely pathogenic germline variants in cancer-related genes among children with acute leukemia in Saudi Arabia.

BACKGROUND: The frequency of pathogenic/likely pathogenic (P/LP) germline mutations in cancer-related genes among children with cancer in highly consanguineous populations is not well studied. METHODS: Whole-exome sequencing of germline DNA was performed in 60 children with acute leukemia. We used the St. Jude Pediatric Cancer Variant Pathogenicity Information Exchange (PeCanPIE) data portal for the classification of germline variants by the St. Jude Medal Ceremony pipeline. RESULTS: Fifty-seven patients had acute lymphoblastic leukemia (ALL) and three patients had acute myeloid leukemia. Parental consanguinity was present in 27 (45%) patients. All patients were of Arab ancestry. Three patients (5%) had a history of cancer in their siblings. Five patients (8.3%) had P/LP germline mutations in cancer-related genes. Three patients with B-ALL had heterozygous pathogenic mutations in TP53, BRCA1, and BRCA2; one patient with B-ALL had homozygous pathogenic mutation in PMS2; and one patient with T-ALL had LP homozygous mutation in AK2 that was associated with reticular dysgenesis. Among patients who had history of parental consanguinity, three (11%) had P/LP germline mutations compared with two (8%) in the absence of parental consanguinity. Fourteen (23%) patients had gold medal variants in cancer-related genes, 13 were heterozygous, and one was homozygous. Silver medal variants were present in 35 (58%) patients; all were heterozygous except one homozygous. CONCLUSIONS: Children with acute leukemia in Saudi Arabia had low frequency of P/LP mutations in cancer-related genes despite the high rate of consanguinity. Larger studies using whole-genome sequencing are needed to further explore the heritability of childhood leukemia.

Prevalence of hereditary cancer susceptibility syndromes in children with cancer in a highly consanguineous population.

BACKGROUND & AIM: Hereditary cancer susceptibility syndromes (HCSS) are reported in up to one-third of children with cancer. Diagnosis of HCSS is crucial for implementation of surveillance protocols. We identified children who fulfilled criteria for HCSS in Saudi Arabia using the American College of Medical Genetics and Genomics (ACMG) guidelines, addressing the utility of these guidelines in a highly consanguineous population. METHODS: This multi-center cross-sectional study recruited 1858 children with cancer between January 2011 and December 2014. HCSS criteria were based on the ACMG guidelines. RESULTS: Seven hundred and four (40.4%) out of 1742 eligible patients fulfilled criteria for HCSS. Consanguinity was reported in 629 (38%) patients, with 50 (2.9%) first-degree, 535 (30.7%) second-degree, and 272 (15.6%) third-degree relatives affected with cancer. Two hundred and eighty eight (17.4%) leukemia and 87 (5.3%) brain tumour patients fulfilled HCSS criteria, with parental consanguinity being the most frequent criterion in both (leukemia 85.4%, brain tumors 83.9%). However, leukemia was less frequent in patients of consanguineous parents (p = 0.023). CONCLUSION: Four out of 10 children with cancer fulfilled criteria for HCSS, most often due to consanguinity. This higher than expected prevalence suggests the need to validate consanguinity as a criterion for HCSS in highly consanguineous populations.

The prevalence of factor VIII and IX inhibitors among Saudi patients with hemophilia: Results from the Saudi national hemophilia screening program.

Hemophilia A and B are X-linked diseases that predominantly affect male patients. Patients can develop coagulation factor inhibitors, which exponentially increases the treatment cost. However, the prevalence of factor VIII and IX inhibitors in Saudi Arabia is unclear.This study aimed to determine the Saudi prevalence of factor VIII and IX inhibitors.This 4-year, 7-center, cross-sectional study evaluated the Saudi prevalences of hemophilia A and B. We collected the patients' clinical data, evaluated their disease, and tested for factor inhibitors.We included 202 patients with hemophilia (median age at diagnosis: 0.13 years, range: birth-34.8 years). The patients included 198 male patients (98%), 148 patients with hemophilia A (73.3%), and 54 patients with hemophilia B (26.7%). The patients exhibited severe factor VIII activity (<1%; 121 patients; 5.2%), moderate activity (1-5%; 7 patients; 4.9%), and mild activity (14 patients; 9.9%). Among the patients with care-related data, most patients were treated for episodic bleeding (76.8%) or received prophylaxis (22.6%); 1 patient received both treatments. Among the patients with source-related data, the factor replacements were derived from plasma (48.4%), recombinant concentrates (22.9%), both sources (14.6%), or fresh frozen plasma (14.1%). Factor VIII inhibitors were observed in 43 (29.3%) of the 147 patients, and only 1 of the 54 patients developed factor IX inhibitors. Most patients who developed inhibitors had severe hemophilia (40/44; 90.9%), and inhibitors were also common among patients who received recombinant products (14/43; 32.6%).The Saudi prevalence of factor inhibitors was similar to those among other ethnic populations.