Evaluating Dosage Optimality for Tofacitinib, an Oral Janus Kinase Inhibitor, in Plaque Psoriasis, and the Influence of Body Weight.

Tofacitinib is an oral Janus kinase inhibitor. An integrated analysis was conducted to evaluate dosage optimality for tofacitinib in patients with moderate-to-severe plaque psoriasis and the impact of body weight on optimality in this patient population. Data were pooled from one phase IIb trial (2, 5, and 15 mg twice daily (b.i.d.)) and four phase III trials (5 and 10 mg b.i.d.). A longitudinal exposure-response model for Psoriasis Area and Severity Index (PASI) improvement (percent change from baseline) was established. Body weight influenced potency; heavier subjects require higher doses to achieve comparable benefit to lighter subjects. Disease severity, sex, and prior biologic usage were also predictive of response. The 10 and 5 mg doses were predicted to achieve 81% and 65%, respectively, of the maximum effect based on a 75% improvement in PASI. The greater efficacy of 10 mg over 5 mg was clinically meaningful.

Effect of tofacitinib withdrawal and re-treatment on patient-reported outcomes: results from a Phase 3 study in patients with moderate to severe chronic plaque psoriasis.

BACKGROUND: Tofacitinib is an oral Janus kinase inhibitor being investigated for psoriasis. A Phase 3 withdrawal/re-treatment study (NCT01186744; OPT Retreatment) showed tofacitinib re-treatment was effective in patients with chronic plaque psoriasis. OBJECTIVES: To describe the effects of tofacitinib withdrawal/re-treatment on health-related quality of life (HRQoL) and disease symptoms measured by patient-reported outcomes (PROs). METHODS: The study was divided into initial treatment, treatment withdrawal, and re-treatment periods. Initial treatment: patients were randomized to receive tofacitinib 5 (n = 331) or 10 mg (n = 335) BID for 24 weeks. Treatment withdrawal: patients who achieved both ≥ 75% reduction in Psoriasis Area and Severity Index (PASI) score from baseline and Physician's Global Assessment of 'clear'/'almost clear' at Week (W)24 received placebo (withdrawal) or the previous dose (continuous treatment). Re-treatment: at relapse (> 50% loss of W24 PASI response) or at W40, patients received their initial tofacitinib dose. PROs included: Dermatology Life Quality Index (DLQI), Itch Severity Item (ISI), Short Form-36 (SF-36) and Patient's Global Assessment (PtGA). RESULTS: After initial treatment with tofacitinib 5 and 10 mg BID, substantial and significant improvements were reported for mean DLQI (baseline: 12.6 and 12.6; W24: 5.1 and 2.6) and ISI (baseline: 6.7 and 6.9; W24: 2.9 and 1.6). Patients continuously treated with tofacitinib 5 and 10 mg BID maintained those improvements through Week 56 (DLQI: 3.0 and 2.1; ISI: 2.3 and 1.4). By W40, patients withdrawn from tofacitinib 5 and 10 mg BID showed worsening in DLQI (5.0 and 6.2) and ISI (3.7 and 4.0) scores; improvements were regained upon re-treatment (W56, DLQI: 3.4 and 2.4; ISI: 2.2 and 1.6). Similar results were reported for PtGA and SF-36. CONCLUSION: Continuous tofacitinib treatment provided sustained improvement in HRQoL and disease symptoms. Patients randomized to treatment withdrawal lost initial improvements. Upon re-treatment, improvements were recaptured to levels comparable to those seen with continuous treatment.

Tofacitinib withdrawal and retreatment in moderate-to-severe chronic plaque psoriasis: a randomized controlled trial.

BACKGROUND: Tofacitinib is an oral Janus kinase inhibitor being investigated for the treatment of moderate-to-severe plaque psoriasis. OBJECTIVES: To compare outcomes following tofacitinib withdrawal with outcomes of continuation. METHODS: In this phase 3 study (NCT01186744), patients received tofacitinib 5 mg (n = 331) or 10 mg (n = 335) twice daily for 24 weeks. The patients who achieved both ≥ 75% reduction in Psoriasis Area and Severity Index (PASI 75) score from baseline and Physician's Global Assessment (PGA) of 'clear' or 'almost clear' (PGA response) received a placebo (withdrawal) or the previous dose. At relapse (> 50% reduction in the PASI improvement during initial treatment) or week 40, the patients received the initial dose. RESULTS: Initial treatment: 33·5% and 55·2% achieved both PASI 75 and PGA responses with tofacitinib 5 and 10 mg twice daily, respectively, making them eligible for the treatment-withdrawal period. Withdrawal: 56·2%, 62·3%, 23·3% and 26·1% maintained PASI 75 responses with tofacitinib 5, 10 mg, placebo (5 mg) and placebo (10 mg) twice daily, respectively; 49·9%, 63·9%, 22·9% and 18·0% maintained PGA responses; and 92·3%, 93·0%, 32·8% and 42·9% did not relapse. Elevations in low-density lipoprotein-cholesterol levels following initial treatment (mean increase: 8·71 mg dL(-1) with 5 mg twice daily, 10·26 mg dL(-1) with 10 mg twice daily) were reversed upon withdrawal. Retreatment: 36·8% and 61·0% of patients who relapsed achieved PASI 75 responses with tofacitinib 5 or 10 mg after 16 weeks; 44·8% and 57·1% regained PGA responses. CONCLUSIONS: Patients who received continuous treatment maintained a response more effectively when compared with placebo recipients. Safety profiles were comparable in both the continuous treatment group and retreatment group. Of those patients who relapsed, up to 60% recaptured a response with tofacitinib.

Influenza vaccines: a review and rationale for use in developed and underdeveloped countries.

Multiple studies have demonstrated that influenza infection results in considerable morbidity and mortality, as well as other economic consequences, such as school and work absenteeism. Influenza vaccine has been shown to be both cost-effective and cost-saving. Despite this, the influenza vaccine appears to be under-utilized throughout the world, with significant variations both between countries and within countries over time. Data will be discussed that provide a rationale for the use of the influenza vaccine to protect the public health. Recommendations for the use of the influenza vaccine in various countries and guidelines for influenza vaccine use worldwide will be proposed.

The association of ATR protein with mouse meiotic chromosome cores.

The ATR (ataxia telangiectasia- and RAD3-related) protein is present on meiotic prophase chromosome cores and paired cores (synaptonemal complexes, SCs). Its striking characteristic is that the protein forms dense aggregates on the cores and SCs of the last chromosomes to pair at the zygotene-pachytene transition. It would appear that the ATR protein either signals delays in pairing or it is directly involved in the completion of the pairing phase. Atm-deficient spermatocytes, which are defective in the chromosome pairing phase, accumulate large amounts of ATR. The behaviour of ATR at meiotic prophase sets it apart from the distribution of the RAD51/DMC1 recombinase complex and our electron microscope observations confirm that they do not co-localize. We failed to detect ATM in association with cores/SCs and we have reported elsewhere that RAD1 protein does not co-localize with DMC1 foci. The expectation that putative DNA-damage checkpoint proteins. ATR, ATM and RAD1, are associated with RAD51/DMC1 recombination sites where DNA breaks are expected to be present, is therefore not supported by our observations.

The C terminus of Ku80 activates the DNA-dependent protein kinase catalytic subunit.

Ku is a heterodimeric protein with double-stranded DNA end-binding activity that operates in the process of nonhomologous end joining. Ku is thought to target the DNA-dependent protein kinase (DNA-PK) complex to the DNA and, when DNA bound, can interact and activate the DNA-PK catalytic subunit (DNA-PKcs). We have carried out a 3' deletion analysis of Ku80, the larger subunit of Ku, and shown that the C-terminal 178 amino acid residues are dispensable for DNA end-binding activity but are required for efficient interaction of Ku with DNA-PKcs. Cells expressing Ku80 proteins that lack the terminal 178 residues have low DNA-PK activity, are radiation sensitive, and can recombine the signal junctions but not the coding junctions during V(D)J recombination. These cells have therefore acquired the phenotype of mouse SCID cells despite expressing DNA-PKcs protein, suggesting that an interaction between DNA-PKcs and Ku, involving the C-terminal region of Ku80, is required for DNA double-strand break rejoining and coding but not signal joint formation. To gain further insight into important domains in Ku80, we report a point mutational change in Ku80 in the defective xrs-2 cell line. This residue is conserved among species and lies outside of the previously reported Ku70-Ku80 interaction domain. The mutational change nonetheless abrogates the Ku70-Ku80 interaction and DNA end-binding activity.

Analysis of the ATM protein in wild-type and ataxia telangiectasia cells.

Ataxia telangiectasia (A-T) is a human disorder that results in a number of clinical symptoms, including cerebellar degeneration and increased cancer predisposition. Recently the gene that is defective in A-T has been cloned and designated ATM. Here, we describe the production of antisera raised against the approximately 350 kDa ATM protein. Antisera specificity is confirmed by them recognising a approximately 350 kDa polypeptide in wild-type cells but not in A-T cells containing mutations that truncate ATM upstream of the antibody binding sites. We show that ATM is almost exclusively nuclear and is expressed in all cell lines and tissues analysed. However, ATM levels are not regulated in response to u.v. or ionising radiation. These data are consistent with ATM being a component of the DNA damage detection apparatus rather than being an inducible downstream effector of the DNA damage response. In addition, we analyse ATM protein expression in a variety of A-T patients. Strikingly, ATM expression is reduced drastically or absent in all patients analysed, including those predicted to express proteins that should be detected by our antisera. Thus, the A-T phenotype may result not only from mutations that disrupt functional domains of ATM, but also from mutations that destabilise the ATM mRNA or protein. Finally, we report that a group of patients displaying an intermediate A-T phenotype express low levels of apparently full-length ATM. This suggests that the ATM pathway is partially active in these individuals and that there is a correlation between levels of residual ATM expression and disease severity.