Maximizing the integration of virtual and experimental screening in hit discovery

INTRODUCTION

Experimental and virtual screening contributes to the discovery of more than 50% of clinical candidates. Considering the similar concept and goals, early-phase drug discovery would benefit from the effective integration of these approaches.

AREAS COVERED

After reviewing the recent trends in both experimental and virtual screening, the authors discuss different integration strategies from parallel, focused, sequential, and iterative screening. Strategic considerations are demonstrated in a number of real-life case studies.

EXPERT OPINION

Experimental and virtual screening are complementary approaches that should be integrated in lead discovery settings. Virtual screening can access extremely large synthetically feasible chemical space that can be effectively searched on GPU clusters or cloud architectures. Experimental screening provides reliable datasets by quantitative HTS applications, and DNA-encoded libraries (DEL) have enlarged the chemical space covered by these technologies. These developments, together with the use of artificial intelligence methods, represent new options for their efficient integration. The case studies discussed here demonstrate the benefits of complementary strategies, such as focused and iterative screening.

Sequential Screening to Improve Behavioral Health Needs Detection in Primary Care

OBJECTIVE

This study evaluates sequential screening to improve behavioral health needs detection, reduce unnecessary referrals, and discern adverse impacts (false negatives) for pediatric primary care populations.

METHOD

Monte Carlo simulation methodology was used to generate performance data for six sequential screening programs based on known technical properties of three broadband behavioral health measures and general psychopathology base rate estimates in pediatric primary care. Descriptive statistics, least-squares power regression, and data visualization were used to compare performance across programs.

RESULTS

Ratio of reduced referrals to net false negatives was differentially affected by measure choice, administration order, and technical properties. Certain screening programs showed greater differences at lower base rates of psychopathology (approximately 12.8:1 ratio at 3% prevalence for SDQ-PSC [SDQ = Strengths and Difficulties Questionnaire, PSC = Pediatric Symptom Checklist] program), despite observed net sensitivity/specificity (0.47/0.97) that was comparable to other programs.

CONCLUSION

Sequential screening is a viable alternative to traditional single-measure behavioral health screening practices in primary care. However, stakeholders must be deliberate with instrument selection and implementation to maximize anticipated benefits and minimize costs. Closer examination of practical issues is necessary to further discern advantages of a screening workflow in pediatric primary care.

Women should decide which conditions matter

Providing reliable prenatal screening performance estimates is critical for patient counseling and policy-making. Women who choose prenatal screening for aneuploidy are likely to be concerned not only with the common aneuploidies but with all causes of intellectual disability and serious birth defects. Sequential prenatal screening (combined serum and ultrasound testing) for aneuploidy detection commonly is offered as a primary screening test. Among women identified as screen positive, cell-free (cf)DNA has been added recently as a secondary, noninvasive screening option, before the consideration of invasive diagnostic testing (eg, amniocentesis and karyotype). With the anticipation of lower costs in the future, cfDNA might be an alternative to sequential screening in the general population. Sequential and cfDNA tests are both noninvasive, and both identify common aneuploidies. Screening via cfDNA detects more common chromosome abnormalities (eg, trisomy 21, sex trisomies). Sequential screening can identify other aneuploidies (eg, triploidy), as well as chromosome abnormalities associated with fetal structural abnormalities. When the advantages and disadvantages of routine sequential screening with routine cfDNA screening are compared, one important measure is the proportion and severity of chromosome abnormalities identified. When reporting these detection rates, authors need to carefully consider the impact of multiple well-described biases. For women to make informed choices in situations of this type, determining reliable comparative performance estimates is crucial.

Where have all the trisomies gone?

Providing reliable prenatal screening performance estimates is critical for patient counseling and policy-making. Women who choose prenatal screening for aneuploidy are likely to be concerned not only with the common aneuploidies but with all causes of intellectual disability and serious birth defects. Sequential prenatal screening (combined serum and ultrasound testing) for aneuploidy detection commonly is offered as a primary screening test. Among women identified as screen positive, cell-free (cf)DNA has been added recently as a secondary, noninvasive screening option, before the consideration of invasive diagnostic testing (eg, amniocentesis and karyotype). With the anticipation of lower costs in the future, cfDNA might be an alternative to sequential screening in the general population. Sequential and cfDNA tests are both noninvasive, and both identify common aneuploidies. Screening via cfDNA detects more common chromosome abnormalities (eg, trisomy 21, sex trisomies). Sequential screening can identify other aneuploidies (eg, triploidy), as well as chromosome abnormalities associated with fetal structural abnormalities. When the advantages and disadvantages of routine sequential screening with routine cfDNA screening are compared, one important measure is the proportion and severity of chromosome abnormalities identified. When reporting these detection rates, authors need to carefully consider the impact of multiple well-described biases. For women to make informed choices in situations of this type, determining reliable comparative performance estimates is crucial.

Cell-free DNA vs sequential screening for the detection of fetal chromosomal abnormalities

BACKGROUND

Sequential and cell-free DNA (cfDNA) screening are both tests for the common aneuploidies. Although cfDNA has a greater detection rate (DR) for trisomy 21, sequential screening also can identify risk for other aneuploidies. The comparative DR for all chromosomal abnormalities is unknown.

OBJECTIVE

To compare sequential and cfDNA screening for detection of fetal chromosomal abnormalities in a general prenatal cohort.

STUDY DESIGN

The performance of sequential screening for the detection of chromosome abnormalities in a cohort of patients screened through the California Prenatal Screening Program with estimated due dates between August 2009 and December 2012 was compared with the estimated DRs and false-positive rates (FPRs) of cfDNA screening if used as primary screening in this same cohort. DR and FPR for cfDNA screening were abstracted from the published literature, as were the rates of "no results" in euploid and aneuploid cases. Chromosome abnormalities in the entire cohort were categorized as detectable (trisomies 13, 18, and 21, and sex chromosome aneuploidy), or not detectable (other chromosome abnormalities) by cfDNA screening. DR and FPR were compared for individual and all chromosome abnormalities. DR and FPR for the cohort were compared if "no results" cases were considered "screen negative" or "screen positive" for aneuploidy. DR and FPR rates were compared by use of the Fisher exact test.

RESULTS

Of 452,901 women who underwent sequential screening during the time period of the study, 2575 (0.57%) had a fetal chromosomal abnormality; 2101 were detected for a DR of 81.6%, and 19,929 euploid fetuses had positive sequential screening for an FPR rate of 4.5%. If no results cases were presumed normal, cfDNA screening would have detected 1820 chromosome abnormalities (70.7%) with an FPR of 0.7%. If no results cases were considered screen positive, 1985 (77.1%) cases would be detected at a total screen positive rate of 3.7%. In either case, the detection rate of sequential screening for all aneuploidies in the cohort was greater than cfDNA (P<.0001).

CONCLUSION

For primary population screening, cfDNA provides lower DR than sequential screening if considering detection of all chromosomal abnormalities. Assuming that no results cfDNA cases are high-risk improves cfDNA detection but with a greater FPR. cfDNA should not be adopted as primary screening without further evaluation of the implications for detection of all chromosomal abnormalities and how to best evaluate no results cases.

Opportunistic screening and health promotion for type 2 diabetes: an expanding public health role for the community pharmacist

BACKGROUND

Early detection to identify people at risk of diabetes is an important approach to prevent or delay type 2 diabetes. This study aimed to implement the Diabetes Prevention Program in community pharmacy using a diabetes risk prediction tool.

METHODS

The program was conducted in seven pharmacies in Bangkok, Thailand. Participants were the pharmacy's clients aged ≥ 35 years without the history of diabetes. A validated risk prediction tool was used to assess individuals' diabetes risk. Educational information was offered to all participants. Those with a high risk score (≥ 9 out of 17) were offered a self-check of fasting capillary blood glucose (CBG). A referral was made for those with CBG ≥ 126 mg/dl.

RESULTS

During a 3-month service, 397 individuals participated in the program. Nearly half of the participants (49.4%) were at a high risk of diabetes (risk score: ≥ 9). Ninety five (48.5%) of these high risk individuals undertook fasting CBG. Elevated fasting CBG (≥ 126 mg/dl) was found in 12 persons (12.7%). Overall, two patients with diabetes were identified during the provision of the program.

CONCLUSIONS

The Diabetes Prevention Program in community pharmacies uncovered half of the clients who were at risk of diabetes and provided an opportunity for participants to learn more about the prevention of diabetes.