Prioritising neonatal medicines research: UK Medicines for Children Research Network scoping survey

Management of patent ductus arteriosus - Evidence to practice

Over the past last 50 years, patent ductus arteriosus (PDA) continues to be the leading hot topic debated worldwide in search of best treatment approach and the uncertainty around whether to treat or not treat a PDA. With the availability of bedside echocardiography and the increasing number of neonatologists acquiring this skill, on one hand there is better understanding of PDA physiology during transitional circulation and objectivity in management, but on the other hand clinicians are uncertain about benefits in health outcomes. Evidence from recent trials utilizing early selective treatment guided by bedside echocardiography should help in dispelling some myths if not providing the answer about how to manage the PDA.

The effects of antibiotic therapy on neonatal sepsis-associated acute kidney injury

AIM

Neonatal sepsis remains one of the most dangerous conditions in the neonatal intensive care units. One of the organs affected by sepsis is the kidney, making acute kidney injury (AKI) a common complication of sepsis. Treatment of sepsis almost always involves antibiotic therapy, which by itself may cause some adverse effects, including nephrotoxicity. We analyzed the mutual effect of antibiotic therapy and sepsis on AKI in an experimental and clinical study in infants and neonatal rats.

MATERIALS AND METHODS

We evaluated the influence of therapy with different antibiotics on the appearance of AKI markers (blood urea nitrogen (BUN), neutrophil gelatinase-associated lipocalin (NGAL), clusterin, interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1), monocyte chemoattractant protein 1 (MCP-1), calbindin, glutation-S-transferase subtype π (GST-π)) and liver injury markers in newborns with or without clinical signs of sepsis in the intensive care unit. In parallel, we analyzed the development of AKI in experimental lipopolysaccharide (LPS)-induced systemic inflammation in newborn rats accompanied by antibiotic therapy.

KEY FINDINGS

We showed that therapy with metronidazole or ampicillin in combination with sulbactam had a beneficial effect in children with suspected sepsis, resulting in a decrease in AKI markers levels. However, treatment of newborns with netilmicin, cefepime, linezolid, or imipenem in combination with cilastatin worsened kidney function in these patients.

SIGNIFICANCE

This prospective study indicates which antibiotics are preferable in neonatal sepsis and which should be used with caution in view of the risk of AKI development.

Drug utilisation in neonatal units in England and Wales: a national cohort study

PURPOSE

To describe drug utilisation patterns in neonatal units.

METHODS

Retrospective observational cohort study using data held in the National Neonatal Research Database (NNRD) for neonatal units in England and Wales including infants born at 23 to 44 weeks' gestational age (GA) from 01 January 2010 to 31 December 2017.

RESULTS

The cohort included 17,501 (3%) extremely preterm infants; 40,607 (7%) very preterm infants; 193,536 (31%) moderate-to-late preterm infants; and 371,606 (59%) term infants. The number of unique drugs received by an infant (median (IQR)) increased with decreasing GA: 17 (11-24) in extremely preterm, 7 (5-11) in very preterm, 3 (0-4) in moderate-to-late preterm, and 3 (0-3) in term infants. The two most frequently prescribed drugs were benzylpenicillin and gentamicin in all GA groups, and caffeine in extremely preterm. Other frequently used drugs among preterm infants were electrolytes, diuretics and anti-reflux medications. Among infants <32 weeks' GA, the largest increase in use was for surfactant (given on the neonatal unit), caffeine and probiotics, while domperidone and ranitidine had the largest decline.

CONCLUSION

Antibiotics, for all GAs and caffeine, among preterm infants, are the most frequently used drugs in neonatal medicine. Preterm infants are exposed to a high burden of drugs, particularly antibiotics. Changing patterns in use reflect the emergence of evidence in some areas but several non-evidence-based drugs continue to be used widely. Improvements are needed to ensure rational drug use on neonatal units.

REGISTRATION

ClinicalTrials.gov (NCT03773289). Date of registration 21 Dec 2018.

Protocol: Pentoxifylline optimal dose finding trial in preterm neonates with suspected late onset sepsis (PTX-trial)

BACKGROUND

Late onset sepsis is a leading cause of death and morbidity in preterm infants. Despite optimal antibiotic treatment, sepsis related mortality and morbidity is still high. Pentoxifylline (PTX) is a methylxanthine with promising immunomodulatory properties, which can be used as an additional therapy next to antibiotics in preterm infants. PTX is increasingly used off-label in neonatal intensive care units, however up till now no dose finding study has been done for PTX in this specific population. The aim of this study (PTX-trial) is to determine the optimal dose of PTX in preterm infants (gestational age < 30 weeks) with (suspected) late onset sepsis. Dose finding in this particular population is unique, since for most drugs used in neonates the optimal dosage has not been investigated in phase II dose-seeking studies.

METHODS

The PTX-trial is a prospective open label sequential dose-optimization study with an adapted continual reassessment method. An up-and-down dose-response design will be used, with dose step-up and step-down titration after every 3 patients. The PTX starting dosage will be 30 mg/kg/day in 6 hours as described in most previous neonatal studies. Efficacy is defined by means of biochemical and clinical parameters. Toxicity in these vulnerable patients is unwarranted. The optimal dose is defined as the ED75 (i.e., clinically and chemically effective dose for 75% of patients) in preterm neonates with late onset sepsis. We plan to include 30 neonates to determine the optimal dose using this study design. Subsequently, the optimal dose will be validated in 10 additional preterm neonates. In parallel, pharmacokinetics of PTX and its metabolites will be described as well as longitudinal evaluation of metabolomics and proteomics.

DISCUSSION

The study has been approved by the Regional Medical Ethics Board of Erasmus Medical Center University Rotterdam (MEC 2019-0477) and registered at Clinicaltrials.gov (NCT04152980). Results of the main trial and each of the secondary endpoints will be submitted for publications in peer-reviewed journals.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT04152980 , Registered November 6th, 2019.

Paediatric pharmacotherapy and drug regulation: Moving past the therapeutic orphan

The development of specific drug therapy for children was a paradigm-changing event that transformed paediatric medical practice. However, a series of tragedies involving drug treatment for children resulted in a gap developing between drug regulation and practice, with the majority of drugs used in child healthcare being used off-label, rendering children therapeutic orphans. Over the past two decades changes in drug regulation led by the US Food and Drug Administration and followed by the European Union's European Medicines Agency have led to substantial changes in how new drugs with potential use in children are studied and labelled. While these changes have substantially improved labelling for new drugs, there has been much less progress with older drugs. Although the unique challenges of conducting clinical research in children have been addressed by novel clinical trial designs, many of these innovations have not been translated into approaches accepted for the drug approval process. The regulations applying to the need for paediatric studies currently are only applicable in the United States and the European Union, and there is less impetus for paediatric labelling in other jurisdictions. This impacts on a number of issues beyond labelling, including the availability of child-friendly formulations. Finally, the impact of Brexit on paediatric drug studies in the UK remains unclear and is subject to ongoing negotiations between the UK government and the European Union.

Review of Drug Utilization Studies in Neonatal Units: A Global Perspective

Rational prescribing is challenging in neonatology. Drug utilization studies help identify and define the problem. We performed a review of the literature on drug use in neonatal units and describe global variations. We searched databases (EMBASE, CINAHL and Medline) from inception to July 2020, screened studies and extracted relevant data (two reviewers). The search revealed 573 studies of which 84 were included. India (n = 14) and the USA (n = 13) reported the most. Data collection was prospective (n = 56) and retrospective (n = 26), mostly (n = 52) from one center only. Sixty studies described general drug use in 34 to 450,386 infants (median (IQR) 190 (91-767)) over a median (IQR) of 6 (3-18) months. Of the participants, 20-87% were preterm. The mean number of drugs per infant (range 11.1 to 1.7, pooled mean (SD) 4 (2.4)) was high with some reporting very high burden (≥30 drugs per infant in 8 studies). This was not associated with the proportion of preterm infants included. Antibiotics were the most frequently used drug. Drug use patterns were generally uniform with some variation in antibiotic use and more use of phenobarbitone in Asia. This study provides a global perspective on drug utilization in neonates and highlights the need for better quality information to assess rational prescribing.

Cross-sectional study of drug utilisation in a Chinese neonatal unit

Objective

This study aimed to describe drug utilisation in a large Chinese neonatal unit and to compare the findings with those from other countries.

Methods

Data were collected from electronic medical records. Prescription drugs were defined as the number of unique medication names for each patient. Medicine doses were defined as the total number of doses of all medicines administered. Information was collected regarding drugs prescribed to inpatients between March 1 and April 1 2018 in the neonatal intensive care unit and the general neonatal ward of West China Second University Hospital.

Results

The 319 neonates received 1276 prescription drugs and 11,410 medicine doses involving 81 drugs. Vitamin K1, hepatitis B vaccine, and cefoperazone-sulbactam were the three most frequently prescribed drugs. Antimicrobials were the most frequently used group of medicines, with cefoperazone-sulbactam and piperacillin-tazobactam the most frequently used in an off-label manner. Domperidone and simethicone were both widely used.

Conclusions

The most commonly prescribed antimicrobials differed greatly from those reported for other countries. The evidence base for the use of some medicines is poor, and is indicative of irrational prescribing.

Top research priorities for preterm birth: results of a prioritisation partnership between people affected by preterm birth and healthcare professionals

Background

We report a process to identify and prioritise research questions in preterm birth that are most important to people affected by preterm birth and healthcare practitioners in the United Kingdom and Republic of Ireland.

Methods

Using consensus development methods established by the James Lind Alliance, unanswered research questions were identified using an online survey, a paper survey distributed in NHS preterm birth clinics and neonatal units, and through searching published systematic reviews and guidelines. Prioritisation of these questions was by online voting, with paper copies at the same NHS clinics and units, followed by a decision-making workshop of people affected by preterm birth and healthcare professionals.

Results

Overall 26 organisations participated. Three hundred and eighty six people responded to the survey, and 636 systematic reviews and 12 clinical guidelines were inspected for research recommendations. From this, a list of 122 uncertainties about the effects of treatment was collated: 70 from the survey, 28 from systematic reviews, and 24 from guidelines. After removing 18 duplicates, the 104 remaining questions went to a public online vote on the top 10. Five hundred and seven people voted; 231 (45%) people affected by preterm birth, 216 (43%) health professionals, and 55 (11%) affected by preterm birth who were also a health professional. Although the top priority was the same for all types of voter, there was variation in how other questions were ranked.

Following review by the Steering Group, the top 30 questions were then taken to the prioritisation workshop. A list of top 15 questions was agreed, but with some clear differences in priorities between people affected by preterm birth and healthcare professionals.

Conclusions

These research questions prioritised by a partnership process between service users and healthcare professionals should inform the decisions of those who plan to fund research. Priorities of people affected by preterm birth were sometimes different from those of healthcare professionals, and future priority setting partnerships should consider reporting these separately, as well as in total.

Adverse Drug Reactions Across the Age Continuum: Epidemiology, Diagnostic Challenges, Prevention, and Treatments

Adverse drug reactions (ADRs) are common and important complications of drug therapy for children. The risk for ADRs changes over childhood, as do the nature and types of ADRs. Importantly, the risk and nature of ADRs in children are markedly different from those of adults, and adult data cannot be relied on to guide safe drug therapy in children. There are groups of children, notably those with complex and chronic diseases, who are at substantial risk for ADRs. The evaluation of an undesired effect during therapy is ideally accomplished by an organized approach that is a skill that clinicians who care for children-especially those children at high risk for ADRs must have. Additionally, clinicians as well as drug regulatory agencies and industry need to be both vigilant and astute as well as aware that ADRs in children are often different in nature and frequency from those in adults. The increasing use of pharmacogenomics to guide drug dosing and the increasing number of biological agents will provide new sets of challenges to clinicians over the next decade.

Adverse Drug Reactions in Children: Pediatric Pharmacy and Drug Safety

An underappreciated problem in child health is the risk for adverse drug reactions (ADRs). While there is an impression that children are at a lower risk than adults for ADRs, in fact a number of factors germane to pediatric therapy place certain groups of children at a high risk for adverse events associated with therapy. Given the importance of drug safety, an understanding of a diagnostic classification for ADRs and of how to approach a possible ADR clinically are key skills for pediatric pharmacists. As drug therapy for children evolves, becomes more complex, and begins to use novel molecules and biologicals there will be an increasing need for pediatric pharmacists to be more involved in clinical care, education, and research specific to drug safety.

Aminoglycoside-induced nephrotoxicity in children

Aminoglycoside antibiotics, in particular gentamicin and tobramycin, are still commonly used in paediatric clinical practice. These drugs cause nephrotoxicity, which particularly affects the proximal tubule epithelial cells due to selective endocytosis and accumulation of aminoglycosides via the multi-ligand receptor megalin. Recent epidemiological studies, using more widely accepted definitions of acute kidney injury (AKI), have suggested that AKI may occur in between 20 and 33 % of children exposed to aminoglycosides. A consensus set of phenotypic criteria for aminoglycoside-induced nephrotoxicity have recently been published. These are specifically designed to provide robust phenotyping for pharmacogenomic studies, but they can pave the way for standardisation for all clinical studies. Novel renal biomarkers, in particular kidney injury molecule-1, identify aminoglycoside-induced proximal tubular injury earlier than traditional markers and have shown promise in observational studies. Further studies need to demonstrate a clear association with clinically relevant outcomes to inform translation into clinical practice. Extended interval dosing of aminoglycosides results in a reduction in nephrotoxicity, but its use needs to become more widespread. Inhibition of megalin-mediated endocytosis by statins represents a novel approach to the prevention of aminoglycoside-induced nephrotoxicity which is currently being evaluated in a clinical trial. Recommendations for future directions are provided.

Neonatal gram-negative infections, antibiotic susceptibility and clinical outcome: an observational study

BACKGROUND

Neonatal gram-negative (GN) infections are associated with high mortality and morbidity. Early appropriate antibiotic treatment is vital and gentamicin is the most frequently used antibiotic on neonatal units (NNUs). Antimicrobial breakpoints are predominantly based on adult data and the relationship between minimum inhibitory concentrations (MICs) and outcome in neonates is unclear. We aimed to determine the MIC of GN pathogens causing neonatal infections and relate this to clinical outcomes.

METHODS

MICs for eight antibiotics plus extended spectrum β-lactamase (ESBL) production were determined for invasive GN bacterial isolates from eight UK NNUs. European Committee on Antimicrobial Susceptibility Testing breakpoints were applied. MIC was correlated with clinical outcome using multivariable regression analysis.

RESULTS

118 isolates from 116 patients were analysed. The median birth gestation and postnatal age was 27 weeks (IQR 24.6-32.3) and 20 days (IQR 5-44), respectively. Pathogens included Escherichia coli (51%), Klebsiella spp (23%) and Enterobacter spp (22%). 10-day attributable mortality was 18.1% (21 patients) with the highest mortality from Pseudomonas aeruginosa infections. ESBL producers accounted for 13.8% of the isolates. In regression analysis, increasing gentamicin MIC was associated with increased mortality in gentamicin treated patients across the full MIC range (OR per log_e increase in MIC: 2.29; 95% CI 1.23 to 4.26, p=0.009), including susceptible isolates only (MIC ≤4) (OR 3.05; 95% CI 1.10 to 8.46, p=0.032).

CONCLUSIONS

Neonatal mortality from GN infections remains high and is associated with increasing gentamicin MIC, even for isolates deemed susceptible. A better understanding of population-specific MICs and aminoglycoside dosing is required to guide empiric antibiotic treatment.

Review of drug utilization patterns in NICUs worldwide

WHAT IS KNOWN AND OBJECTIVES

When considering acute care settings, such as the neonatal intensive care unit (NICU), the inappropriate use of medicines poses a great risk to vulnerable babies at the start of their lives. However, there is limited published literature that explores the current medication management practices in NICUs and where the main misuse issues lie. Therefore, the purpose of this review was to give an overview of medicine use in NICUs worldwide and identify therapeutic areas requiring more targeted pharmaceutical care. Specific objectives include the following: identifying the most commonly used medicines, comparing these to the A-PINCH (Anti-infectives, Potassium and other electrolytes, Insulin, Narcotics and sedatives, Chemotherapy agents, Heparin and other anticoagulants), high-risk medicines list, and determining whether there are any differences in medicine use between countries.

METHOD

Quasi-systematic literature review.

SEARCH STRATEGY

Google Scholar, MEDLINE/PubMed, Scopus and EMBASE were searched utilizing selected MeSH terms.

RESULTS

A total of 19 articles from 12 countries were reviewed. Medication use between countries was very similar with no discernible differences in types of medicines prescribed. The most commonly used medicines included gentamicin, ampicillin, caffeine, furosemide and vitamin K. The median number of medicines prescribed per patient ranged from 3 to 11, and an inverse relationship was identified between gestational age and the number of medications that were prescribed. Nine of the 20 most commonly used medicines were listed as A-PINCH medicines, and included antibiotics, fentanyl, morphine and heparin. Inappropriate prescribing, as well as the high use of off-label/unlicensed medicines, was highlighted as areas of practice that require consideration to improve medication safety and minimize the potential risk for medication errors.

WHAT IS NEW AND CONCLUSION

Overall, the types of medicines used in NICUs worldwide are similar, with consistent reports on the common use of antibiotics, caffeine and vitamins. However, it cannot be definitively stated that the findings of the review accurately depict current practice in NICUs, due to the limited amount of published literature available. There are several areas of concern that warrant further investigation to improve rational use of medicines in the neonatal populations, including high use of antibiotics and off-label and unlicensed medicines.

Development and Evaluation of a Gentamicin Pharmacokinetic Model That Facilitates Opportunistic Gentamicin Therapeutic Drug Monitoring in Neonates and Infants

Trough gentamicin therapeutic drug monitoring (TDM) is time-consuming, disruptive to neonatal clinical care, and a patient safety issue. Bayesian models could allow TDM to be performed opportunistically at the time of routine blood tests. This study aimed to develop and prospectively evaluate a new gentamicin model and a novel Bayesian computer tool (neoGent) for TDM use in neonatal intensive care. We also evaluated model performance for predicting peak concentrations and the area under the concentration-time curve from time 0 h to time t h (AUC0- t). A pharmacokinetic meta-analysis was performed on pooled data from three studies (1,325 concentrations from 205 patients). A 3-compartment model was used with the following covariates: allometric weight scaling, postmenstrual and postnatal age, and serum creatinine concentration. Final parameter estimates (standard errors) were as follows: clearance, 6.2 (0.3) liters/h/70 kg of body weight; central volume (V), 26.5 (0.6) liters/70 kg; intercompartmental disposition (Q), 2.2 (0.3) liters/h/70 kg; peripheral volume V2, 21.2 (1.5) liters/70 kg; intercompartmental disposition (Q2), 0.3 (0.05) liters/h/70 kg; peripheral volume V3, 148 (52.0) liters/70 kg. The model's ability to predict trough concentrations from an opportunistic sample was evaluated in a prospective observational cohort study that included data from 163 patients and 483 concentrations collected in five hospitals. Unbiased trough predictions were obtained; the median (95% confidence interval [CI]) prediction error was 0.0004 (-1.07, 0.84) mg/liter. Results also showed that peaks and AUC0- t values could be predicted (from one randomly selected sample) with little bias but relative imprecision, with median (95% CI) prediction errors being 0.16 (-4.76, 5.01) mg/liter and 10.8 (-24.9, 62.2) mg · h/liter, respectively. neoGent was implemented in R/NONMEM and in the freely available TDMx software.

Clinical trials of medicines in neonates: the influence of ethical and practical issues on design and conduct

In the past, there has been a perception that ethical and practical problems limit the opportunities for research in neonates. This perception is no longer appropriate. It is now clear that research about the medicines used in neonates is an ethical requirement. It is possible to conduct high quality research in neonates if the research team adapt to the characteristics of this population. Good practice involves respecting the specific needs of newborn babies and their families by adopting relevant approaches to study design, recruitment, pharmacokinetic studies and safety assessment. Neonatal units have a unique culture that requires careful development in a research setting. Clinical investigators need to recognize the clinical and ethical imperative to conduct rigorous research. Industry needs to engage with neonatal networks early in the process of drug development, preferably before contacting regulatory agencies. Follow-up over 3-5 years is essential for the evaluation of medicines in neonates and explicit funding for this is required for the assessment of the benefit and risk of treatments given to sick newborn babies. The views of parents must be central to the development of studies and the research agenda. Ethical and practical problems are no longer barriers to research in neonates. The current challenges are to disseminate good practice and maximize capacity in order to meet the need for research among newborn babies.

Drug utilisation profile in the neonatal unit of a university hospital: a prospective observational study in Brazil

BACKGROUND

Advances in neonatology have contributed to changes in the drug utilisation profile in neonates, both in the number of drugs and the pharmacotherapeutic groups.

OBJECTIVE

To analyse drug use in the neonatal care unit of a teaching hospital in Brazil and to evaluate the associations among perinatal, clinical care and drug use data.

SETTING

The neonatal care unit of a teaching hospital in Brazil.

METHODS

A prospective observational study was conducted. Perinatal, clinical care and pharmacotherapy data were collected from the patients' medical records. Labelling information regarding neonatal use was analysed for prescribed drugs. The data were analysed using univariate descriptive statistics and quasi-Poisson regression.

MAIN OUTCOME MEASURE

Frequency of drug use by gestational age.

RESULTS

The study included 187 patients; 157 (84.0 %) received drugs. The mean gestational age was 35.8 weeks. The mean number of drugs prescribed per patient was 6.4. The number of drugs used was inversely correlated to gestational age and birth weight. The most commonly prescribed drugs belonged to the following anatomical therapeutic chemical groups: nervous system drugs, anti-infectives for systemic use, and alimentary tract and metabolism drugs. Information regarding neonatal use was given in the labelling of only 20.5 % of the prescribed drugs. Of these, only 9.5 % had information specific for preterm infants.

CONCLUSIONS

Drug administration to neonates is frequently and inversely correlated to gestational age and birth weight. Neonates are exposed to different therapeutic classes, reflecting scientific advances in neonatology. In Brazil, the percentage of drugs with neonate-specific labelling information is low. Consequently, there is an evident need for efforts to guarantee effective and safe pharmacotherapy for neonates.

Aminoglycoside toxicity in neonates: something to worry about?

Toxicity has limited the use of aminoglycosides and adult studies report high rates of both ototoxicity and nephrotoxicity. Conversely paediatric studies have shown lower rates and extended interval dosing may have reduced toxicity further. We review the animal and human evidence for aminoglycoside toxicity in neonates including mechanisms, measurement and rates of toxicity; and differences between aminoglycosides and dosing regimens. We discuss genetic susceptibility and the impact of other synergistic effects.

Educational paper: do we need neonatal clinical pharmacologists?

Effective and safe drug administration in young infants should be based on integrated knowledge concerning the evolving physiological characteristics of the infant who will receive the drug and the pharmacokinetic and pharmacodynamic characteristics of a given drug. Consequently, clinical pharmacology in neonates is as dynamic and diverse as the neonates we are entitled to take care of. Even more than median estimates, covariates of variability within the population are of clinical relevance. We aim to illustrate the complexity and the need for neonatal clinical pharmacology based on the gap between current and likely best clinical practice for two commonly administered compounds (aminoglycosides for infection and ibuprofen for patent ductus arteriosus) and one new compound (bevacizumab, to treat threshold retinopathy of prematurity). Progression has been made to render pharmacokinetic studies child size, e.g., low volume samples, optimal study design, and population pharmacokinetics. Challenges to further improve clinical pharmacology in neonates include, when appropriate, the validation of off-patent drug dosing regimens and of infant-tailored formulations. Knowledge integration, i.e., the use of available data to improve current drug use and to predict pharmacokinetics/pharmacodynamics for similar compounds is needed. Development of clinical research networks is helpful to achieve these goals.

Drug research and treatment for children in Canada: A challenge

Historically, children have been 'therapeutic orphans'. Many drugs have not been studied or labelled for use in children and adolescents, making the development and definition of optimally safe and effective drug therapies for the paediatric age group an ongoing challenge. Over the past decade, networks have developed in the United States and Europe to enhance drug research for this group, while no comparable evolution has occurred in Canada. The present statement provides context for the Canadian situation and makes recommendations that address two pressing needs: for more drug research focused on Canadian children and adolescents, including dedicated support for such research; and for increasing human capacity to undertake targeted studies. These initiatives should be undertaken collaboratively, nationally and internationally, and include strategic, innovative approaches to the unique problems and ethical issues posed by drug research in this population.

Neonatal drug development

Drug development is crucial to improving the care given to neonates through new and existing medicines. Pressure from regulatory agencies has improved the way in which pharmaceutical companies work with neonates. This provides new opportunities for the neonatal community. This paper describes the issues that arise during the development of new drugs and considers how the contemporary approach to new drugs can inform research on existing drugs.