Vitamin D deficiency and its correction in children with sickle cell anaemia.

Vitamin D deficiency is common in sickle cell anaemia (SCA, HbSS), although its significance and optimal means of correction are unknown. We conducted an audit to assess the clinical significance of 25-hydroxy vitamin D (25-OHD) deficiency in children with SCA and to evaluate two methods of vitamin D supplementation. We audited 25-OHD levels in 81 children with SCA and looked for statistical associations with biochemical, haematological and clinical parameters. In a separate group of regularly transfused children with SCA, we compared changes in 25-OHD blood concentrations following treatment with either high-dose intramuscular ergocalciferol (n = 15) or 4 days of high-dose oral cholecalciferol (n = 64). Ninety-one percent of children with SCA had 25-OHD levels <20 µg/L. The 25-OHD levels were negatively correlated with increasing age (P < 0.001) but showed no significant relationship to laboratory measurements, transcranial Doppler velocities or hospital attendance. Both intramuscular ergocalciferol and oral cholecalciferol supplementations resulted in increases of 25-OHD blood concentration to normal levels. The mean dose of ergocalciferol was greater than that of cholecalciferol (7,729 versus 5,234 international units (IU)/kg, P < 0.001), but the increment in 25-OHD levels was significantly greater in the oral cholecalciferol group (6.44 versus 2.82 (ng/L)/(IU/kg), P < 0.001). Both approaches resulted in vitamin D sufficiency for about 120 days. Increased 25-OHD concentration was significantly associated with increased serum calcium concentration. Vitamin D deficiency is very common in SCA and can be effectively corrected with high-dose intramuscular ergocalciferol or 4 days of high-dose oral cholecalciferol. Prospective, randomised studies are needed to assess the clinical value of vitamin D supplementation.

Effect of low-level BCR-ABL1 kinase domain mutations identified by next-generation sequencing in patients with chronic myeloid leukaemia: a population-based study.

BACKGROUND: Kinase domain mutations in BCR-ABL1 are associated with resistance to tyrosine kinase inhibitors in patients with chronic myeloid leukaemia. Next-generation sequencing (NGS) allows detection of low-level kinase domain mutations, but its relevance in clinical practice remains debated. We aimed to examine the clinical effects of low-level kinase domain mutations identified using NGS in patients with chronic myeloid leukaemia. METHODS: In this population-based study, we included consecutive patients newly diagnosed with chronic myeloid leukaemia treated with first-line tyrosine kinase inhibitors, and patients identified at the time of resistance to first-line treatment with imatinib at six institutions (teaching hospitals and district hospitals) in southeast England. We screened patients for BCR-ABL1 kinase domain mutations using NGS, irrespective of patient response to tyrosine kinase inhibitor therapy. When we detected a mutation with NGS, we retrospectively analysed all previous samples to establish the date of first occurrence and subsequent kinetics of the mutant subclone (or subclones). The primary endpoints of this study were progression-free and event-free survival at 5 years. FINDINGS: Between Feb 1, 2007, and Dec 31, 2014, we screened 121 patients with chronic myeloid leukaemia for BCR-ABL1 kinase domain mutation. 99 consecutive patients were newly diagnosed, with available sequential RNA stored. The remaining 22 patients were diagnosed between June 1, 1999, and June 30, 2006, and were screened at the time of resistance to first-line treatment with imatinib. Imatinib was the first-line treatment for 111 patients, nilotinib for seven patients, and dasatinib for three patients. We detected a kinase domain mutation in 25 (21%) of 121 patients. Low-level kinase domain mutations were first identified in 17 (68%) of 25 patients with mutation. For patients with a complete cytogenetic response, 13 (14%) of 93 patients screened had a mutation. Five (71%) of the seven patients with a clinically relevant mutation lost complete cytogenetic response compared with 15 (17%) of 86 patients without a clinically relevant mutation (80 patients without mutation and six patients with a tyrosine kinase inhibitor-sensitive mutation, p=0·0031). Patients harbouring a mutant clone had poorer 5-year progression-free survival (65·3% [95% CI 40·5-81·8] vs 86·9% [75·8-93·2]; p=0·0161) and poorer 5-year event-free survival (22·2% [CI 5·6-45·9] vs 62·0% [50·4-71·6]; p<0·0001) than did patients without a mutation. We identified a kinase domain mutation in four (10%) of 41 patients with samples available at 3 months after starting first-line tyrosine kinase inhibitor treatment; all four subsequently progressed to accelerated phase disease compared with only three (8%) of 37 without a mutation (p<0·0001). INTERPRETATION: NGS reliably and consistently detected early appearance of kinase domain mutations that would not otherwise be detected by Sanger sequencing. For the first time, to our knowledge, we report the presence of kinase domain mutations after only 3 months of therapy, which could have substantial clinical implications. NGS will allow early clinical intervention and our findings will contribute to the establishment of new recommendations on the frequency of kinase domain mutation analysis to improve patient clinical care. FUNDING: None.

The safety and efficacy of hydroxycarbamide in infants with sickle cell anemia.

The BABYHUG study is the first randomized controlled prospective trial of hydroxycarbamide in infants with sickle cell anemia to look at its effect on organ function. Almost 200 patients were recruited, irrespective of disease severity, over a 3-year period and followed for 2 years. The primary end points of splenic function and glomerular filtration rate were not reached. The trial did show a benefit in frequency of pain, dactylitis, acute chest syndrome, hospital admissions and transfusion requirements. Adverse effects were low.