6,103 research outputs found
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Global Financing and Long-Term Technical Assistance for Multidrug-Resistant Tuberculosis: Scaling Up Access to Treatment
Thomas Hwang and Salmaan Keshavjee argue that a market-based strategy combined with long-term in-country technical assistance should be used to scale-up access to the treatment of multi-drug resistant tuberculosis Please see later in the article for the Editors' Summar
Mutation supply and the repeatability of selection for antibiotic resistance
Whether evolution can be predicted is a key question in evolutionary biology.
Here we set out to better understand the repeatability of evolution. We
explored experimentally the effect of mutation supply and the strength of
selective pressure on the repeatability of selection from standing genetic
variation. Different sizes of mutant libraries of an antibiotic resistance
gene, TEM-1 -lactamase in Escherichia coli, were subjected to different
antibiotic concentrations. We determined whether populations went extinct or
survived, and sequenced the TEM gene of the surviving populations. The
distribution of mutations per allele in our mutant libraries- generated by
error-prone PCR- followed a Poisson distribution. Extinction patterns could be
explained by a simple stochastic model that assumed the sampling of beneficial
mutations was key for survival. In most surviving populations, alleles
containing at least one known large-effect beneficial mutation were present.
These genotype data also support a model which only invokes sampling effects to
describe the occurrence of alleles containing large-effect driver mutations.
Hence, evolution is largely predictable given cursory knowledge of mutational
fitness effects, the mutation rate and population size. There were no clear
trends in the repeatability of selected mutants when we considered all
mutations present. However, when only known large-effect mutations were
considered, the outcome of selection is less repeatable for large libraries, in
contrast to expectations. Furthermore, we show experimentally that alleles
carrying multiple mutations selected from large libraries confer higher
resistance levels relative to alleles with only a known large-effect mutation,
suggesting that the scarcity of high-resistance alleles carrying multiple
mutations may contribute to the decrease in repeatability at large library
sizes.Comment: 31pages, 9 figure
Therapeutic Value of Drugs Granted Accelerated Approval or Conditional Marketing Authorization in the US an Europe From 2007 to 2021
IMPORTANCE: The number of drugs approved through the accelerated approval or conditional marketing authorization pathways has increased with unclear evidence of their therapeutic value. OBJECTIVES: To assess the therapeutic value of drug indications granted accelerated approval in the US or conditional marketing authorization in the European Union (EU) overall and for cancer indications. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used the public databases of the US Food and Drug Administration and the European Medicines Agency to identify all drugs (initial and supplemental indications) granted accelerated approval in the US or conditional marketing authorization (initial indications only) in the EU between January 1, 2007, and December 31, 2021. Therapeutic value ratings were obtained from national health authorities in Germany, France, and Canada. MAIN OUTCOMES AND MEASURES: Descriptive statistics were used to assess the proportion of accelerated approvals and conditional marketing authorizations overall and for cancer vs noncancer indications rated as having high added therapeutic value. RESULTS: The cohort included 146 drug indications (94 first indications, 52 supplemental indications) in the US and 58 (all first indications) in the EU. Most drugs were approved for cancer (122 [83.6%] in the US; 40 [69.0%] in the EU). Therapeutic value ratings were available for 90 drug indications (61.6%) in the US and 56 (96.6%) in the EU. Overall, 35 drug indications granted accelerated approval (38.9%) and 21 granted conditional marketing authorization (37.5%) had high added therapeutic value in the US and EU, respectively, at the time of approval. The proportions of indications rated as having high added therapeutic value were 36.0% (27 of 75) for cancer vs 53.3% (8 of 15) for noncancer indications in the US and 30.8% (12 of 39) for cancer vs 52.9% (9 of 17) for noncancer indications in the EU. CONCLUSIONS AND RELEVANCE: In this cohort study, among new drug indications approved through the accelerated approval or conditional marketing authorization pathways in the US and Europe from 2007 to 2021, 38.9% and 37.5%, respectively, demonstrated high therapeutic value. A substantially lower proportion of cancer indications than noncancer indications were rated as having high therapeutic value. Policy makers and regulators should increase enforcement of timely postapproval study completion for drugs qualifying for these pathways
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New Regulatory Paradigms for Innovative Drugs to Treat Pediatric Diseases
Effects of Hypohydration on Muscular Performance in Females: An Ongoing Study
Dehydration (~3%) has been shown to negatively affect anaerobic performance. A majority of this research has been conducted using male participants. Like males, females have been shown to underestimate sweat loss, which could lead to insufficient rehydration and thus hypohydration. Additionally, due to differences in thermoregulation, it is possible that females respond to hypohydration differently than males. To date, no research has examined the effects of previous night dehydration on muscular performance in females. PURPOSE: The purpose of this ongoing study was to determine the effects of previous night dehydration on muscular strength, muscular endurance, lower body power, and perceptual measures in resistance trained females. METHODS: Healthy, resistance trained females (n = 7) completed two bouts of resistance exercise, either dehydrated (~3% body weight) (DT) or heat exposed with fluid replacement (HT). Each exercise bout consisted of one rep maximum (1RM) for bench press followed by 5 sets to failure of 75% of 1RM, 1RM for leg press followed by 5 sets to failure of 75% of 1RM, and vertical jump assessment. Participants estimated ratings of perceived exertion (RPE) after each exercise. Session RPE (SRPE) was estimated 5 minutes following completion of the protocol and estimations for feelings of recovery (PRS), perceived readiness to exercise (PR), thirst, and sleep quality were estimated prior to workouts. RESULTS: Analysis revealed a bench press 1RM (p = 0.05) and leg press 1RM (p = 0.03) were significantly lower for DT (bench: 95.0 ± 34.0; leg press: 461.4 ± 141.7) compared to HT (bench: 97.9 ± 34.3; leg press: 500.0 ± 141.0). There was no difference in total reps completed for bench press (p = 0.32) or leg press (p = 0.37) for DT (bench press: 31.0 ± 6.7; leg press: 47.9 ± 21.6) compared to HT (bench press: 31.7 ± 5.0; leg press: 49.6 ± 22.8). There was no significant difference (p = 0.15) for vertical jump height (DT: 17.6 ± 2.2, HT: 18.1 ± 2.6). RPE was not significantly different following bench press (p = 0.5) (DT: 7.1 ± 1.1, HT: 7.1 ± 0.9) or leg press (p = 0.41) (DT: 6.7 ± 0.5, HT: 6.9 ± 1.7). SRPE was significantly higher (p = 0.05) for DT (6.6 ± 0.5) vs HT (5.9 ± 0.7). Significant differences for PRS (p = 0.03) (DT: 5.4 ± 2.2, HT: 7.05 ± 1.3) and PR (p = 0.01) (DT: 3.9 ± 0.9, HT: 2.6 ± 0.5) indicate participants expected impaired performance during DT. Feelings of thirst were significantly higher (p = 0.001) for DT (6.5 ± 2.5) vs HT (2.1 ± 2.3). Estimations of sleep quality were significantly lower (p = 0.05) for DT (4.3 ± 3.3) vs HT (7.2 ± 2.1). CONCLUSION: Even though only preliminary data from a presently ongoing study, the current results suggest that previous night dehydration has a negative influence on both performance and perceptual measures in resistance trained females
Model for the Quasifree Polarization-Transfer Measurements in the (p,n) reaction at 495 MeV
The recent (p,n) polarization transfer experiments at LAMPF are explained in
terms of a dropping rho-meson mass in the medium.Comment: 12 pages of text (LATEX), 4 figures (not included, available from the
authors). February 199
Coverage of new drugs in medicare Part D
Context: Medicare Part D is an outpatient prescription drug benefit for older Americans covering over 46 million beneficiaries. Except for mandatory coverage for essentially all drugs in six “protected classes”, plans have substantial flexibility in how they design their formularies: which drugs are covered, which drugs are subject to restrictions, and what factors determine formulary placement. Our objective in this paper was to document the extent to which Part D plans limit coverage of newly approved drugs. Methods: We examined the formulary design of 4,582 Part D plans from 2014 through 2018 and measured (1) the decision to cover newly approved drugs in non-protected classes, (2)nuse of utilization management tools in protected and non-protected classes, and (3) the association between plan design and drug-level characteristics such as 30-day cost, therapeutic benefit, and the US Food and Drug Administration (FDA) expedited regulatory pathway. Findings: The FDA approved 109 new drugs predominantly used in outpatient settings between 2013 and 2017. Of these, 75 fell outside of the six protected drug classes. One-fifth of drugs in non-protected classes (15 out of 75) were covered by more than half of plans during the first year after approval. Coverage was often conditional on utilization management strategies in both protected and non-protected classes: only 7 drugs (6 percent) were covered without prior authorization requirements in more than half of plans. Higher 30-day drug costs were associated with more widespread coverage in non-protected classes: drugs that cost less than 30,000 per 30 days were covered by more than 50 percent of plans. Plans were also more likely to implement utilization management tools on high-cost drugs in both protected and non-protected classes. A higher proportion of plans implemented utilization management strategies on covered drugs with first-in-class status than drugs that were not first-in-class. Other drug characteristics, including availability of added therapeutic benefit and inclusion in FDA expedited regulatory approval, were not consistently associated with plan coverage or formulary restrictions. Conclusions: Newly approved drugs are frequently subject to formulary exclusions and restrictions in Medicare Part D. Ensuring that formulary design in Part D is linked closely to the therapeutic value of newly approved drugs would improve patients’ welfare
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