Functional and metagenomic level diversities of human gut symbiont-derived glycolipids.

Bioactive metabolites produced by symbiotic microbiota causally impact host health and disease, nonetheless, incomplete functional annotation of genes as well as complexities and dynamic nature of microbiota make understanding species-level contribution in production and actions difficult. Alpha-galactosylceramides produced by Bacteroides fragilis (BfaGC) are one of the first modulators of colonic immune development, but biosynthetic pathways and the significance of the single species in the symbiont community still remained elusive. To address these questions at the microbiota level, we have investigated the lipidomic profiles of prominent gut symbionts and the metagenome-level landscape of responsible gene signatures in the human gut. We first elucidated the chemical diversity of sphingolipid biosynthesis pathways of major bacterial species. In addition to commonly shared ceramide backbone synthases showing two distinct intermediates, alpha-galactosyltransferase (agcT), the necessary and sufficient component for BfaGC production and host colonic type I natural killer T (NKT) cell regulation by B. fragilis, was characterized by forward-genetics based targeted metabolomic screenings. Phylogenetic analysis of agcT in human gut symbionts revealed that only a few ceramide producers have agcT and hence can produce aGCs, on the other hand, structurally conserved homologues of agcT are widely distributed among species lacking ceramides. Among them, alpha-glucosyl-diacylglycerol(aGlcDAG)-producing glycosyltransferases with conserved GT4-GT1 domains are one of the most prominent homologs in gut microbiota, represented by Enterococcus bgsB . Of interest, aGlcDAGs produced by bgsB can antagonize BfaGC-mediated activation of NKT cells, showing the opposite, lipid structure-specific actions to regulate host immune responses. Further metagenomic analysis of multiple human cohorts uncovered that the agcT gene signature is almost exclusively contributed by B. fragilis , regardless of age, geographical and health status, where the bgsB signature is contributed by >100 species, of which abundance of individual microbes is highly variable. Our results collectively showcase the diversities of gut microbiota producing biologically relevant metabolites in multiple layers-biosynthetic pathways, host immunomodulatory functions and microbiome-level landscapes in the host.

Estimated Medicaid Spending on Original and Citrate-Free Adalimumab From 2014 Through 2021.

This cross-sectional study assesses Medicaid spending associated with citrate-free vs original adalimumab.

Clinical Benefit and Expedited Approval of Cancer Drugs in the United States, European Union, Switzerland, Japan, Canada, and Australia.

PURPOSE: Regulatory agencies have sought to speed up the review of new cancer medicines and reduce delays in approval between countries. We examined trends in regulatory review times and association with clinical benefit for new cancer medicines in six jurisdictions: United States (Food and Drug Administration [FDA]), European Union (European Medicines Agency [EMA]), Switzerland (Swissmedic), Japan (Pharmaceuticals and Medical Devices Agency [PMDA]), Canada (Health Canada), and Australia (Therapeutic Goods Administration). METHODS: We studied all new cancer drugs approved in the six aforementioned jurisdictions from 2007 to 2020. We extracted all applicable expedited programs, total regulatory review times, and, for drugs first approved by the FDA, times to subsequent regulatory approval. Clinical benefit was assessed using the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale value framework and ASCO-Cancer Research Committee's targets. Nonparametric Kruskal-Wallis test was used to compare total review times for high versus low clinical benefit drugs. RESULTS: One hundred and twenty eight drugs received initial approval in at least one of the six included jurisdictions. Most drugs approved by the FDA (91%) and Health Canada (59%) qualified for at least one expedited program within those jurisdictions, compared with 46% of EMA approvals and 18% of PMDA approvals. The FDA was the first regulator to approve 102 (80%) drugs. Delays in submission accounted for a median of 20.2% (EMA) to 83.8% (PMDA) of the time to subsequent approval. There was no association between high clinical benefit and shorter total review times. CONCLUSION: Most new cancer therapies were approved first by the FDA, and delays in submission of regulatory applications accounted for substantial delays in approving cancer drugs in other countries. Regulators should prioritize faster review for drugs with high clinical benefit.

Host immunomodulatory lipids created by symbionts from dietary amino acids.

Small molecules derived from symbiotic microbiota critically contribute to intestinal immune maturation and regulation1. However, little is known about the molecular mechanisms that control immune development in the host-microbiota environment. Here, using a targeted lipidomic analysis and synthetic approach, we carried out a multifaceted investigation of immunomodulatory α-galactosylceramides from the human symbiont Bacteroides fragilis (BfaGCs). The characteristic terminal branching of BfaGCs is the result of incorporation of branched-chain amino acids taken up in the host gut by B. fragilis. A B. fragilis knockout strain that cannot metabolize branched-chain amino acids showed reduced branching in BfaGCs, and mice monocolonized with this mutant strain had impaired colonic natural killer T (NKT) cell regulation, implying structure-specific immunomodulatory activity. The sphinganine chain branching of BfaGCs is a critical determinant of NKT cell activation, which induces specific immunomodulatory gene expression signatures and effector functions. Co-crystal structure and affinity analyses of CD1d-BfaGC-NKT cell receptor complexes confirmed the interaction of BfaGCs as CD1d-restricted ligands. We present a structural and molecular-level paradigm of immunomodulatory control by interactions of endobiotic metabolites with diet, microbiota and the immune system.

Analysis of Launch and Postapproval Cancer Drug Pricing, Clinical Benefit, and Policy Implications in the US and Europe.

IMPORTANCE: The high cost of cancer medicines is a public health challenge. Policy makers in the US and Europe are debating reforms to drug pricing that would cover both the prices of new medicines when entering the market and price increases after they are launched. OBJECTIVE: To assess launch prices, postlaunch price changes, and clinical benefit of cancer drugs in the US compared with 3 European countries (England, Germany, and Switzerland). DESIGN, SETTING, AND PARTICIPANTS: This economic evaluation identified all new drugs that were approved for use in the US, England, Germany, and Switzerland with initial indications for treatment of adult solid tumor and hematologic cancers. Analysis included drugs approved by the US Food and Drug Administration between January 1, 2009, and December 31, 2019, and by the European Medicines Agency and Swissmedic until December 31, 2019. Prices were adjusted for currency and inflation. Clinical benefit of drugs indicated for solid tumors was assessed using the American Society of Clinical Oncology Value Framework and European Society for Medical Oncology Magnitude of Clinical Benefit Scale. Using Spearman rank correlation coefficients, correlations between clinical benefit and launch prices and postlaunch price changes for each country were evaluated. MAIN OUTCOMES AND MEASURES: Launch prices, postlaunch price changes, and clinical benefit of cancer drugs. RESULTS: The cohort included 65 drugs: 47 (72%) approved for solid tumors and 18 (28%) for hematologic cancers. In all countries, the lowest median monthly treatment costs at launch were greater in 2018-2019 vs 2009-2010: $14 580 vs $5790 in the US, $5888 vs $4289 in Germany, $6593 vs $5784 in Switzerland, and $6867 vs $3939 in England. Between 2009 and 2019, 48 of 65 (74%) cancer drugs had price increases in the US that were greater than inflation. Only 1 of 62 (2%) drugs in England, 0 of 60 drugs in Germany, and 7 of 56 drugs (13%) in Switzerland had a median price increase greater than inflation. There were no associations between launch prices or postlaunch price changes and clinical benefit in any assessed country. CONCLUSIONS AND RELEVANCE: During this economic evaluation study period, launch prices of cancer drugs were substantially higher in the US than in the assessed similar high-income European countries, a gap that increased in the years after approval. Cancer drug prices frequently increased faster than inflation in the US but decreased on inflation-adjusted terms in Europe. Price changes were not associated with clinical benefit in any country.

Cost to Medicare of Delayed Adalimumab Biosimilar Availability.

Launched in 2002, originator adalimumab (Humira) is the top revenue-generating drug in the United States. Between 2016 and 2019, the US Food and Drug Administration approved 5 adalimumab biosimilars, yet none have been marketed owing to patent dispute settlements. We sought to calculate the cost of this delayed entry to Medicare over this period by estimating the difference between reported spending on originator adalimumab and estimated spending on originator and biosimilar adalimumab products assuming timely biosimilar market entry. Estimates of potential biosimilar spending were calculated based on the following evidence-based projections: (i) market capture of 15% for the first biosimilar and 5.5% for successive biosimilars in their first year on the market, and 5% annually thereafter; (ii) price reductions of 3.5% per year and 2.4% per additional biosimilar entry for originator adalimumab; and (iii) price discounts of 25% at launch, 3.4% per year, and 1.7% per additional biosimilar entry for biosimilar adalimumab. Based on these assumptions, had adalimumab biosimilars launched upon approval, estimated non-rebate spending on them would have been $18.3 million in 2016, $225.7 million in 2017, $436.2 million in 2018, and $727.7 million in 2019, whereas estimated non-rebate spending on originator adalimumab would have been $2.33 billion, $2.04 billion, $1.78 billion, and $1.42 billion. Cumulative spending on adalimumab would have thus been $8.98 billion instead of an observed $12.11 billion. Accounting for estimated rebates, total predicted savings would have been $2.19 billion. Reforms for timely biosimilar availability will be critical in ensuring optimal savings for Medicare after biosimilar approval.

Factors Associated With Generic Drug Uptake in the United States, 2012 to 2017.

OBJECTIVES: In the United States, brand-name prescription drugs remain expensive until market exclusivity ends and lower-cost generics become available. Delayed generic drug uptake may increase spending and worsen medication adherence and patient outcomes. We assessed recent trends and factors associated with generic uptake. METHODS: Among 227 drugs facing new generic competition from 2012 to 2017, we used a national claims database to measure generic uptake in the first and second year after generic entry, defined as the proportion of claims for a generic version of the drug. Using linear regression, we evaluated associations between generic uptake and key drug characteristics. RESULTS: Mean generic uptake was 66.1% (standard deviation 22.1%) in the first year and 82.7% (standard deviation 21.6%) in the second year after generic entry. From 2012 to 2017 generic uptake decreased 4.3% per year in the first year (95% confidence interval, 2.8%-5.8%, P < .001) and 3.2%/year in the second year (95% confidence interval, 1.2%-5.1%). Generic uptake was lower for injected than oral drugs in the first year (38.5% vs 70.0%, P < .001) and second year (50.3% vs 86.9%, P < .001). In the second year, generic uptake was higher among drugs with an authorized generic (86.1 vs 80.1%, P = .045) and those with ≥3 generic competitors (87.7% vs 78.6%, P = .055). CONCLUSION: Early generic uptake decreased over the past several years. This trend may adversely affect patients and increase prescription drug spending. Policies are needed to encourage generic competition, particularly among injected drugs administered in a hospital or clinic setting.

Market Exclusivity Length for Drugs with New Generic or Biosimilar Competition, 2012-2018.

Brand-name drugs have periods of market exclusivity before generic competition begins. Due to high brand-name drug prices charged during this period, market exclusivity is an important determinant of US prescription drug spending. We used claims data to estimate the market exclusivity period for 264 small molecule and 4 biologic drugs that faced new generic or biosimilar competition from 2012-2018. Exclusivity periods were longer for biologics compared with new small molecule drugs (median 21.5 vs. 14.4 years, P = 0.02), longer for drugs with annual revenue < $75 million compared with those with revenue ≥ $500 million (16.6 vs. 14.2 years, P = 0.01), and shorter in cases for which the first generic was granted 180 days of exclusivity, which is an incentive designed to expedite generic competition (14.1 vs. 15.9 years, P < 0.01). Modified versions of existing products had shorter exclusivities than new drugs (9.9 vs. 14.5 years, P < 0.01), with variation by route of administration, therapeutic area, and use of expedited approval pathways. Exclusivity periods for new drugs ranging from 13-17 years are similar to older estimates, but longer exclusivity among the small number of biologics in the cohort raises concern that overall median exclusivity may lengthen in the future because biologics represent a larger fraction of new drug approvals over the last decade than they did the previous decade. Unnecessarily long exclusivity periods delay patient access to lower-priced medications, and policymakers should consider options to encourage timely competition, particularly among biologic drugs.

An Overview Of Vaccine Development, Approval, And Regulation, With Implications For COVID-19.

The Food and Drug Administration (FDA) approves vaccines when their benefits outweigh the risks for their intended use. In this article we review the standard FDA approach to vaccine evaluation, which underpins its current approaches to assessment of vaccines to prevent coronavirus disease 2019 (COVID-19). The FDA has established pathways to accelerate vaccine availability before approval, such as Emergency Use Authorization, and to channel resources to high-priority products and allow more flexibility in the evidence required for approval, including accelerated approval based on surrogate markers of effectiveness. Among the thirty-five new vaccines approved in the US from 2006 through October 2020, about two-thirds of their pivotal trials used the surrogate outcome of immune system response, and only one-third evaluated actual disease incidence. Postapproval safety surveillance of new vaccines, and particularly vaccines receiving expedited approval, is crucial. This has generally been accomplished through such mechanisms as the Centers for Disease Control and Prevention (CDC) and FDA Vaccine Adverse Event Reporting System, the CDC Vaccine Safety Datalink, and the CDC Clinical Immunization Safety Assessment Project. Adverse events detected in this way may lead to changes in a vaccine's recommended use or withdrawal from the market. Regulatory oversight of new vaccines must balance speed with rigor to effectively address the pandemic.

Clinical Development Times for Biosimilars in the United States.

Biosimilars are versions of biologic drugs made by different manufacturers that can help lower spending by promoting competition. However, few biosimilars are currently available in the US. To assess the role of testing requirements in this outcome, we investigated clinical development times for 40 biosimilars that initiated phase I testing between 2012 and 2015. We found that most biosimilars underwent phase III testing with an average trial length of 22 months. Of 20 biosimilars that had been approved by October 2019, the median time from initiation of phase I testing to approval was 69.9 months. These findings reveal a high testing bar for approval that likely contributed to limited market entry.

Associations Between Patient-Reported Outcome Measures of Asthma Control and Psychosocial Symptoms.

There is growing emphasis on using patient-reported outcome measures to enhance clinical practice. This study was a retrospective review of scores on the Childhood Asthma Control Test (C-ACT) and the Pediatric Symptom Checklist-17 (PSC-17) at a pediatric primary care center in Boston, Massachusetts. A total of 218 patients were selected at random using billing codes for well-child (WC) care and asthma, excluding complex medical conditions. Cutoff scores were used to identify uncontrolled asthma (C-ACT ⩽19) and clinically significant psychosocial symptoms (+PSC-17). Multiple logistic regression was used to measure associations between C-ACT ⩽19 and +PSC-17, adjusting for covariates. In multivariable analysis, C-ACT ⩽19 at WC visits was associated with +PSC-17 at WC visits (adjusted odds ratio = 3.2 [95% confidence interval = 1.3-8.6]). C-ACT ⩽19 at non-WC visits was also associated with +PSC-17 at WC visits (adjusted odds ratio = 3.1 [95% confidence interval = 1.2-8.9]). Patient-reported outcome measures of asthma control and psychosocial symptoms were positively correlated in this sample.

Seasonal changes in diet and chemical defense in the Climbing Mantella frog (Mantella laevigata).

Poison frogs acquire chemical defenses from the environment for protection against potential predators. These defensive chemicals are lipophilic alkaloids that are sequestered by poison frogs from dietary arthropods and stored in skin glands. Despite decades of research focusing on identifying poison frog alkaloids, we know relatively little about how environmental variation and subsequent arthropod availability impacts alkaloid loads in poison frogs. We investigated how seasonal environmental variation influences poison frog chemical profiles through changes in the diet of the Climbing Mantella (Mantella laevigata). We collected M. laevigata females on the Nosy Mangabe island reserve in Madagascar during the wet and dry seasons and tested the hypothesis that seasonal differences in rainfall is associated with changes in diet composition and skin alkaloid profiles of M. laevigata. The arthropod diet of each frog was characterized into five groups (i.e. ants, termites, mites, insect larvae, or 'other') using visual identification and cytochrome oxidase 1 DNA barcoding. We found that frog diet differed between the wet and dry seasons, where frogs had a more diverse diet in the wet season and consumed a higher percentage of ants in the dry season. To determine if seasonality was associated with variation in frog defensive chemical composition, we used gas chromatography / mass spectrometry to quantify alkaloids from individual skin samples. Although the assortment of identified alkaloids was similar across seasons, we detected significant differences in the abundance of certain alkaloids, which we hypothesize reflects seasonal variation in the diet of M. laevigata. We suggest that these variations could originate from seasonal changes in either arthropod leaf litter composition or changes in frog behavioral patterns. Although additional studies are needed to understand the consequences of long-term environmental shifts, this work suggests that alkaloid profiles are relatively robust against short-term environmental perturbations.

Medicare Spending on Brand-name Combination Medications vs Their Generic Constituents.

Importance: Brand-name combination drugs can be more expensive than the sum of their components, especially when the constituent products are available as generic medications. The potential savings that could be achieved using generic components is not known. Objective: To estimate the additional cost to Medicare of prescribing brand-name combination medications instead of generic constituents. Design, Setting, and Participants: Retrospective analysis for 2011 through 2016 using the Medicare data set of Part D beneficiaries prescribed any of the 1500 medications that accounted for the highest total spending in 2015. Brand-name combination drugs that had identical or therapeutically equivalent generic constituents were included. Exposures: Brand-name, oral combination medications with constituents available either as generic drugs or therapeutically equivalent generic substitutes. Main Outcomes and Measures: The estimated difference between the amount spent by Medicare on brand-name combination drugs and the estimated amount that would have been spent on substitutable generic components. Results: Among the 1500 medications evaluated, 29 brand-name combination medications were separated into 3 mutually exclusive categories: constituents available as generic medications at identical doses (n = 20), generic constituents at different doses (n = 3), and therapeutically equivalent generic substitutes (n = 6). For the constituents available as generic medications at identical doses category, total spending by Medicare in 2016 on the brand-name combination products was $303 million and the estimated spending for the generic constituents would have been $68 million, which is an estimated difference of $235 million. For the generic constituents at different doses category, total spending by Medicare in 2016 on the brand-name combination products was $232 million and the estimated spending for the generic constituents would have been $13 million, which is an estimated difference of $219 million. For the therapeutically equivalent generic substitutes category, total spending by Medicare in 2016 on the brand-name combination products was $491 million and the estimated spending for the generic constituents would have been $20 million, which is an estimated difference of $471 million. In 2016, the estimated spending for the generic constituents for these 29 drugs would have been $925 million less than the estimated spending for the brand-name combinations. For the 10 most costly combination products available during the entire study period, the listed Medicare spending could have been an estimated $2.7 billion lower between 2011 and 2016 if the generic constituents had been prescribed. Conclusions and Relevance: In 2016, the difference between the amount that the Medicare drug benefit program reported spending on brand-name combination medications and the estimated spending for generic constituents for the same number of doses was $925 million. Promoting generic substitution and therapeutic interchange through prescriber education and more rational substitution policies may offer important opportunities to achieve substantial savings in the Medicare drug benefit program.