Global haemostatic tests demonstrate the absence of parameters of hypercoagulability in non-hypoxic mild COVID-19 patients: a prospective matched study.

Severe COVID-19 patients demonstrate hypercoagulability, necessitating thromboprophylaxis. However, less is known about the haemostatic profile in mild COVID-19 patients. We performed an age and gender-matched prospective study of 10 severe and 10 mild COVID-19 patients. Comprehensive coagulation profiling together with Thromboelastography and Clot Waveform Analysis were performed. FBC, PT, APTT, D-dimer, fibrinogen and CWA were repeated every 3 days for both groups and repeat TEG was performed for severe patients up till 15 days. On recruitment, severe patients had markers reflecting hypercoagulability including raised median D-dimer 1.0 µg/mL (IQR 0.6, 1.4) (p = 0.0004), fibrinogen 5.6 g/L (IQR 4.9, 6.6) (p = 0.002), Factor VIII 206% (IQR 171, 203) and vWF levels 265.5% (IQR 206, 321). Mild patients had normal values of PT, aPTT, fibrinogen and D-dimer, and slightly elevated median Factor VIII and von Willebrand factor (vWF) levels. Repeated 3-day assessments for both groups showed declining trends in D-dimer and Fibrinogen. CWA of severe COVID-19 group demonstrated hypercoagulability with an elevated median values of aPTT delta change 78.8% (IQR 69.8, 85.2) (p = 0.001), aPTT clot velocity (min1) 7.8%/s (IQR 6.7, 8.3) (p = 0.001), PT delta change 22.4% (IQR 19.4, 29.5) (p = 0.004), PT min1 7.1%/s (IQR 6.3, 9.0) (p = 0.02), PT clot acceleration (min 2) 3.6%/s2 (IQR 3.2, 4.5) (p = 0.02) and PT clot deceleration (max2) 2.9%/s2 (IQR 2.5, 3.5) (p = 0.02). TEG of severe patients reflected hypercoagulability with significant increases in the median values of CFF MA 34.6 mm (IQR 27.4,38.6) (p = 0.003), CRT Angle 78.9° (IQR 78.3, 80.0) (p = 0.0006), CRT A10 67.6 mm (IQR 65.8, 69.6) (p = 0.007) and CFF A10 32.0 mm (IQR 26.8, 34.0) (p = 0.003). Mild COVID-19 patients had absent hypercoagulability in both CWA and TEG. 2 severe patients developed thromboembolic events while none occurred in the mild COVID-19 group. Mild COVID-19 patients show absent parameters of hypercoagulability in global haemostatic tests while those with severe COVID-19 demonstrated parameters associated with hypercoagulability on the global haemostatic tests together with raised D-Dimer, fibrinogen, Factor VIII and vWF levels.

Low incidence of venous thrombosis but high incidence of arterial thrombotic complications among critically ill COVID-19 patients in Singapore.

BACKGROUND: Arterial and venous thrombosis are reported to be common in critically ill COVID-19 patients. METHOD AND RESULTS: This is a national multicenter retrospective observational study involving all consecutive adult COVID-19 patients who required intensive care units (ICU) admission between 23 January 2020 and 30 April 2020 in Singapore. One hundred eleven patients were included and the venous and arterial thrombotic rates in ICU were 1.8% (n = 2) and 9.9% (n = 11), respectively. Major bleeding rate was 14.8% (n = 16). CONCLUSIONS: Critically ill COVID-19 patients in Singapore have lower venous thromboembolism but higher arterial thrombosis rates and bleeding manifestations than other reported cohorts.

COVID-19 associated coagulopathy in critically ill patients: A hypercoagulable state demonstrated by parameters of haemostasis and clot waveform analysis.

Patients with COVID-19 are known to be at risk of developing both venous, arterial and microvascular thrombosis, due to an excessive immuno-thrombogenic response to the SARS-CoV-2 infection. Overlapping syndromes of COVID-19 associated coagulopathy with consumptive coagulopathy and microangiopathy can be seen in critically ill patients as well. Blood was collected from 12 Intensive Care Unit (ICU) patients with severe COVID-19 who were on either mechanical ventilation or on high flow oxygen with a PaO2/FiO2 ratio of <300 mmHg. Laboratory tests were performed for parameters of haemostasis, clot waveform analysis and anti-phospholipid antibodies. CWA parameters were raised with elevated aPTT median Min1 (clot velocity) 9.3%/s (IQR 7.1-9.9%/s), elevated PT median Min1 10.3%/s (IQR 7.1-11.1%/s), elevated aPTT median Min2 (clot acceleration) 1.5%/s2 (IQR 1.0-1.6%/s2), elevated PT median Min2 5.2%/s2 (3.6-5.7%/s2), elevated aPTT median Max2 (clot deceleration) 1.3%/s2 (IQR 0.8-1.4%/s2) elevated PT median Max2 3.8%/s2 (IQR 2.6-4.2%/s2), increased aPTT median Delta change (decreased light transmission due to increased clot formation) 87.8% (IQR 70.2-91.8%) and PT median Delta change 33.0%. This together with raised median Factor VIII levels of 262.5%, hyperfibrinogenemia (median fibrinogen levels 7.5 g/L), increased median von Willebrand factor antigen levels 320% and elevated median D-dimer levels 1.7 µg/dl support the diagnosis of COVID-19 associated coagulopathy. A lupus anticoagulant was present in 50% of patients. Our laboratory findings further support the view that severe SARS-CoV-2 infection is associated with a state of hypercoagulability.

Tolerability of Daratumumab Amongst Asian Patients with Plasma Cell Dyscrasias - A Single Centre Experience.

Daratumumab is increasingly incorporated into the standard treatment regimens for patients with plasma cell dyscrasias in Asia, especially with cost-containment measures implemented by various regional health authorities. This analysis aimed to study daratumumab's tolerability amongst Asian patients. This is a retrospective medical records review of patients who received daratumumab between November 2016 and August 2021 as part of routine clinical care. Sixty-two patients were included in the study: 62.9% had renal impairment, and 27.4% had creatinine clearance (CrCl) \<30ml/min. Forty-five patients (72.6%) received daratumumab combination therapy, with a median 1 line of prior therapy. The median duration of follow-up was 12.4 months, and the median duration patients were on treatment with daratumumab was 12.3 months. Twenty-one of 62 (33.9%) patients experienced infusion-related reactions (IRRs) after the first dose of intravenous daratumumab. Seven developed mostly grades 1 and 2 respiratory events, and 14 showed grades 1 and 2 non-respiratory IRRs. Only one patient experienced a grade 1 IRR with the second infusion, with none developing any IRRs in the third or subsequent infusions. Eight (12.9%) patients were affected by hematological adverse events (AEs), mostly grades 2 and 3, with one experiencing grade-4 neutropenia without sepsis. Six (9.7%) patients experienced non-hematological AEs, the commonest being pneumonia and other infections, with one developing Nocardia pneumonia (grade 4) 14 months after the initiation of daratumumab. In conclusion, daratumumab is tolerable amongst Asian patients, including the elderly, and patients with severe renal impairment and chronic lung diseases.

Daratumumab-Based Therapeutic Approaches and Clinical Outcomes in Multiple Myeloma and other Plasma Cell Dyscrasias: Insights from a Nationwide Real-World Chart Review Study.

Singapore leads Southeast Asia in the routine use of daratumumab for multiple myeloma and other plasma cell dyscrasias. This retrospective review analyzed 112 patients who received daratumumab between 2012 and 2020. Tolerability, and efficacy based on prior lines (PL) of therapy, cytogenetic risk group, and the presence of renal impairment were presented. Infusion-related reactions occurred in 26.8% of patients. Grades 1 and 2 hematological and non-hematological adverse events were observed in 14.3% and 33.9% of patients, respectively. After a median follow-up of 16.9 months, there was no significant difference in overall response rates (ORR) (86% versus 76.3%, p = 0.082) or depth of response (≥ complete response (CR), 35.1% versus 28.9%, p = 0.469) between myeloma patients with and without renal dysfunction. Newly diagnosed and relapsed/refractory patients had an ORR of 92% and 76.3%, and a ≥ VGPR (very good partial response) rate of 80% and 55.3%, respectively. Median progression-free survival (PFS) was better for patients with 0/1 PL compared to ≥ 2 PLs (19.8 versus 6.2 months, p < 0.001), with a deeper response (≥ CR, 38.5% versus 16.7%, p = 0.033). Forty-six and a half percentage of patients had high-risk FISH abnormalities, and those with 0/1 PL had a significantly better ORR than those with ≥ 2 PLs (83.3% vsersus 47.1%, p = 0.022), achieving an ORR similar to that of the general cohort (80.2%, p = 0.905). In conclusion, positioning daratumumab in earlier lines of therapy leads to better outcomes and may mitigate the impact of high-risk FISH abnormalities.

Anaphylatoxin Complement 5a in Pfizer BNT162b2-Induced Immediate-Type Vaccine Hypersensitivity Reactions.

The underlying immunological mechanisms of immediate-type hypersensitivity reactions (HSR) to COVID-19 vaccines are poorly understood. We investigate the mechanisms of immediate-type hypersensitivity reactions to the Pfizer BNT162b2 vaccine and the response of antibodies to the polyethylene glycol (PEG)ylated lipid nanoparticle after two doses of vaccination. Sixty-seven participants, median age 35 and 77.3% females who tolerated two doses of the BNT162b2 vaccine (non-reactors), were subjected to various blood-sampling time points. A separate group of vaccine reactors (10 anaphylaxis and 37 anonymised tryptase samples) were recruited for blood sampling. Immunoglobulin (Ig)G, IgM and IgE antibodies to the BNT162b2 vaccine, biomarkers associated with allergic reaction, including tryptase for anaphylaxis, complement 5a(C5a), intercellular adhesion molecule 1 (ICAM-1) for endothelial activation and Interleukin (IL)-4, IL-10, IL-33, tumour necrosis factor (TNF) and monocyte chemoattractant protein (MCP-1), were measured. Basophil activation test (BAT) was performed in BNT162b2-induced anaphylaxis patients by flow cytometry. The majority of patients with immediate-type BNT162b2 vaccine HSR demonstrated raised C5a and Th2-related cytokines but normal tryptase levels during the acute reaction, together with significantly higher levels of IgM antibodies to the BNT162b2 vaccine (IgM 67.2 (median) vs. 23.9 AU/mL, p < 0.001) and ICAM-1 when compared to non-reactor controls. No detectable IgE antibodies to the BNT162b2 vaccine were found in these patients. The basophil activation tests by flow cytometry to the Pfizer vaccine, 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol (DMG-PEG) and PEG-2000 were negative in four anaphylaxis patients. Acute hypersensitivity reactions post BNT162b2 vaccination suggest pseudo-allergic reactions via the activation of anaphylatoxins C5a and are independent of IgE-mechanisms. Vaccine reactors have significantly higher levels of anti-BNT162b2 IgM although its precise role remains unclear.

Reference range for ADAMTS13 antigen, activity and anti-ADAMTS13 antibody in the healthy adult Singapore population

INTRODUCTION: ADAMTS13 (a disintegrin-like and metalloproteinase with a thrombospondin Type 1 motif, member 13) plays a fundamental role in the regulation of haemostasis and thrombosis. Its deficiency leads to an accumulation of ultra-large von Willebrand multimers, inducing spontaneous platelet aggregation, thrombosis in the microvasculature, and thrombotic thrombocytopenic purpura (TTP), a condition with 90% mortality when left untreated. Prompt quantification of ADAMTS13 antigen, activity and autoantibody plays a crucial role in the diagnosis and management of TTP and can help differentiate it from other thrombotic microangiopathies (TMAs). Reference ranges for ADAMTS13 are generally derived from Caucasian patients. Given that polymorphism in the ADAMTS13 gene can be associated with variable ADAMTS13 levels, we aimed to establish the first reference range in Singapore and provide a crucial laboratory test for institutions here and elsewhere. METHODS: 150 healthy voluntary donors (75 men, 75 women) aged 21-60 years, with an ethnic mix mirroring Singapore's population profile, were recruited. ADAMTS13 antigen, activity and autoantibody levels were measured using the fluorescence resonance energy transfer-vWF73 and enzyme-linked immunosorbent assay methodologies. RESULTS: Levels (activity 0.65-1.79 IU/mL, antigen 0.36-1.17 IU/mL, autoantibody 1.4-12.5 U/mL) were not statistically different between the genders and various age groups. CONCLUSION: TTP and TMAs are encountered in a wide range of specialties. The availability of new assays in Singapore will aid clinicians in the timely management of these conditions. Standardising reference ranges established for Singapore against World Health Organization standards allows harmonisation of measurements between laboratories and for future research collaborations.

TPMT and NUDT15 testing for thiopurine therapy: A major tertiary hospital experience and lessons learned.

Variants in thiopurine methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15) are associated with an accumulation of cytotoxic metabolites leading to increased risk of drug-related toxicity with standard doses of thiopurine drugs. We established TPMT and NUDT15 genetic testing for clinical use and evaluated the utilization, service outcomes and potential value of multi-gene PGx testing for 210 patients that underwent pharmacogenetics (PGx) testing for thiopurine therapy with the aim to optimize service delivery for future prescribing. The test was most commonly ordered for Gastroenterology (40.0%) and Neurology (31.4%), with an average turnaround time of 2 days. Following testing, 24.3% patients were identified as intermediate or poor metabolizers, resulting in 51 recommendations for a drug or dose change in thiopurine therapy, which were implemented in 28 (54.9%) patients. In the remaining patients, 14 were not adjusted and 9 had no data available. Focusing on drug gene interactions available for testing in our laboratory, multi-gene PGx results would present opportunities for treatment optimization for at least 33.8% of these patients who were on 2 or more concurrent medications with actionable PGx guidance. However, the use of PGx panel testing in clinical practice will require the development of guidelines and education as revealed by a survey with the test providers. The evaluation demonstrated successful implementation of single gene PGx testing and this experience guides the transition to a pre-emptive multi-gene testing approach that provides the opportunity to improve clinical care.

Classic myeloproliferative neoplasms in Singapore: A population-based study on incidence, trends, and survival from 1968 to 2017.

BACKGROUND: Current descriptive epidemiological information on classic myeloproliferative neoplasms (MPNs) is incomplete. Published data among Asian population are particularly sparse. METHODS: We conducted a large population-based study to determine the incidence rates and survival patterns of MPN reported to the Singapore Cancer Registry during the period 1968-2017. Age-standardised incidence rates(ASR), overall survival, 5-/10-year relative survival ratio (RSR) were estimated. Joinpoint regression was used to evaluate quinquennial percent change (QPC) in incidence. RESULTS: We identified 2557 individuals diagnosed with MPN including 1031 chronic myeloid leukaemia (CML), 424 polycythaemia vera (PV), 389 essential thrombocythaemia (ET), 134 primary myelofibrosis (PMF) and 579 MPN unclassifiable (MPN-U). The overall respective ASRs per 100,000 for CML, PV, ET, PMF and MPN-U were 1.24, 1.15, 1.07, 0.43, and 0.80 in 2013-2017. Males had higher ASR than females in all MPNs. A gradual rise in incidence trends of CML was observed between 1968 and 2017 (QPC 2.1%, 95% CI -0.9, 5.3). The overall incidence trends of non-CML MPNs including PV (QPC 62.9%, 95% CI 19.3, 122.6), ET (QPC 54.2%, 95% CI 23.5, 92.3) and PMF (QPC 103.5%, 95% CI 19.1, 247.6) increased sharply during 1993-2017. Survival was lower in MPNs compared with expected survival in general population: 5-year RSRs were 0.82 (95% CI 0.78, 0.86), 0.96 (95% CI 0.91, 1.01), 0.96 (95% CI 0.92, 1.01), 0.53 (95% CI 0.43, 0.65), and 0.74 (95% CI 0.68, 0.80) for CML, PV, ET, PMF and MPN-U respectively. CONCLUSION: CML incidence has increased marginally, whereas non-CML MPNs incidences have sharply increased. MPN patients have a lower relative survival compared to the general population, and patients with PV and ET have the most favourable relative survival. Median survival for CML patients has increased dramatically over the last 50 years.

Compound Heterozygous Factor VII Deficiency c.1025G>A p.(Arg342Gln) With Novel Missense Variant c.194C>G p.(Ala65Gly).

Factor VII (FVII) deficiency manifests as prolonged prothrombin time (PT) and reduced FVII activity. We report a case of an asymptomatic 60-year-old gentleman with discrepancies in PT and FVII coagulant activity levels (FVII:C) on three different thromboplastin reagents used. Further sequence analysis on genomic DNA showed double heterozygosity for c.1025G>A p.Arg342Gln and c.194C>G p.Ala65Gly in the F7 gene. To date, p.Ala65Gly in exon 2 of the F7 gene represents a novel variant in patients with FVII deficiency and is classified as likely pathogenic. Computational prediction tools support a deleterious effect on the gene. The genotype-phenotype association and the clinical significance of this exon 2 missense variant is proposed in this case report.

Efficacy and safety of bosutinib versus imatinib for newly diagnosed chronic myeloid leukemia in the Asian subpopulation of the phase 3 BFORE trial.

Bosutinib is approved in the United States, Europe, Japan, and other countries for treatment of newly diagnosed chronic phase (CP) chronic myeloid leukemia (CML), and CML resistant/intolerant to prior therapy. In the phase 3 BFORE trial (Clinicaltrials.gov, NCT02130557), patients were randomized 1:1 to first-line bosutinib or imatinib 400 mg once daily. We examined efficacy, safety, and patient-reported outcomes of bosutinib vs imatinib and pharmacokinetics of bosutinib in the Asian (n = 33 vs 34) and non-Asian (n = 235 vs 234) subpopulations of BFORE followed for at least 24 months. At the data cutoff date, 72.7 vs 66.7% of Asian and 70.6 vs 66.4% of non-Asian patients remained on treatment. The major molecular response rate at 24 months favored bosutinib vs imatinib among Asian (63.6 vs 38.2%) and non-Asian (60.9 vs 52.6%) patients, as did the complete cytogenetic response rate by 24 months (86.7 vs 76.7%, 81.5 vs 76.3%). Treatment-emergent adverse events in both subpopulations were consistent with the primary BFORE results. Trough bosutinib concentration levels tended to be higher in Asian patients. Health-related quality of life was maintained after 12 months of bosutinib in both subpopulations. These results support bosutinib as a first-line treatment option in Asian patients with CP CML.