Warning letters to sponsor-investigators at academic health centres - the regulatory "canaries in a coal mine".

PURPOSE: This study highlights Warning Letter (WL) findings issued to sponsor-investigators (S-Is) by the Food and Drug Administration (FDA). METHODS: The online index of WLs issued from October 1, 2007 through September 30, 2012 was reviewed [1]. Through a manual screening process, letters were evaluated if specifically issued to 'clinical investigators', 'sponsors' or 'sponsor-investigators'. A particular focus was given to S-Is at Academic Health Centres (AHCs). Each letter was scored for the presence of violations in 40 general regulatory categories. RESULTS: A review of FDA WLs issued over a five-year period (FDA Fiscal Years 2008-2012) revealed that WLs to S-Is represent half of the WLs issued to all sponsors (16 of 32 letters). A review of these letters indicates that S-Is are not aware of, or simply do not meet, their regulatory responsibilities as either investigators or sponsors. In comparing total sponsor letters to those of S-Is, the most cited violation was the same: a lack of monitoring. A review of publicly available inspection data indicates that these 16 letters merely represent the tip of the iceberg. CONCLUSION: This review of the WL database reveals the potential for serious regulatory violations among S-Is at AHCs. Recent translational funding initiatives may serve to increase the number of S-Is, especially among Academic Health Centres (AHCs) [2]; thus, AHCs must become aware of this S-I role and work to support investigators who assume both roles in the course of their research.

Combined Dietary Nitrate and Exercise Intervention in Peripheral Artery Disease: Protocol Rationale and Design.

BACKGROUND: Peripheral artery disease (PAD) is caused by atherosclerotic occlusions in the legs. It affects approximately 8-12 million people in the United States alone, one-third of whom suffer from intermittent claudication (IC), defined as ischemic leg pain that occurs with walking and improves with rest. Patients with IC suffer a markedly impaired quality of life and a high perception of disability. Improving pain-free walking time is a primary goal of rehabilitation in this population. OBJECTIVE: The nitric oxide (NO)-PAD trial is designed to compare the effects that 12 weeks of supervised exercise training, in combination with a high inorganic nitrate-content (beetroot [BR] juice) beverage or placebo (PL) beverage, has on clinical outcomes of exercise and functional capacity in two groups of PAD+IC patients: exercise training plus beetroot (EX+BR) and exercise training plus placebo (EX+PL). The primary aims of this randomized controlled, double-blind pilot study are to determine group differences following 12 weeks of EX+BR versus EX+PL in the changes for (1) exercise capacity: pain-free walking time (claudication onset time, COT), peak walk time (PWT), and maximal exercise capacity (peak oxygen uptake, VO2peak) during a maximal-graded cardiopulmonary exercise test (max CPX) and (2) functional capacity: 6-minute walk (6MW) distance. The secondary aims will provide mechanistic insights into the exercise outcome measures and will include (1) gastrocnemius muscle oxygenation during exercise via near-infrared spectroscopy (NIRS); (2) gastrocnemius muscle angiogenesis: capillaries per unit area and per muscle fiber, and relative fraction of type I, IIa, IIb, and IId/x fibers; and (3) vascular health/function via brachial artery flow-mediated dilation, lower-limb blood flow via plethysmography, and pulse wave velocity and reflection. METHODS: A total of 30 subjects between 40 and 80 years of age with PAD who are limited by IC will undergo exercise training 3 days per week for 12 weeks (ie, 36 sessions). They will be randomized to either the EX+BR or EX+PL group where participants will consume a beverage high in inorganic nitrate (4.2 mmol) or a low-nitrate placebo, respectively, 3 hours prior to each training session. RESULTS: Data collection from this study has been completed and is in the process of analysis and write-up. While the study is too underpowered-EX+BR, n=11; EX+PL, n=13-to determine between-group differences in the primary outcomes of COT, PWT, and 6MW, preliminary observations are promising with Cohen d effect sizes of medium to large. CONCLUSIONS: Exercise training is currently the most effective therapy to increase functional capacity in PAD+IC. If the addition of inorganic nitrate to an exercise regimen elicits greater benefits, it may redefine the current standard of care for PAD+IC. TRIAL REGISTRATION: ClinicalTrials.gov NCT01684930; https://clinicaltrials.gov/ct2/show/NCT01684930 (Archived by WebCite at http://www.webcitation.org/6raXFyEcP).

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer.

Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

Genetic analysis of the requirements for SOS induction by nalidixic acid in Escherichia coli.

Nalidixic acid, the prototype antibacterial quinolone, induces the SOS response by a mechanism that requires the RecBCD nuclease/helicase. A key step inferred for this induction pathway is the conversion of a drug-induced gyrase cleavage complex into a DNA break that can be processed by RecBC. We tried to clarify the nature of this step by searching for additional gene products that are specifically necessary for SOS induction following nalidixic acid treatment. A transposon library of approximately 19,000 insertion mutants yielded 18 mutants that were substantially reduced for SOS induction following nalidixic acid but not UV treatment, and which were also hypersensitive to nalidixic acid. All 18 mutants turned out to have insertions in recB or recC. As expected, recA insertion mutants were uncovered as being uninducible by either nalidixic acid or UV treatment. Insertions in 11 other genes were found to cause partial defects in SOS induction by one or both pathways, providing possible leads in understanding the detailed mechanisms of SOS induction. Overall, these results suggest that nalidixic acid-induced DNA breaks are generated either by RecBC itself, by redundant activities, and/or by an essential protein that could not be uncovered with transposon mutagenesis.

ClinicalTrials.gov reporting: strategies for success at an academic health center.

The Food and Drug Administration Amendments Act of 2007 (FDAAA 2007, US Public Law 110-98) mandated registration and reporting of results for applicable clinical trials. Meeting these registration and results reporting requirements has proven to be a challenge for the academic research community. Duke Medicine has made compliance with registration and results reporting a high priority. In order to create uniformity across a large institution, a written policy was created describing requirements for clinical trials disclosure. Furthermore, a centralized resource group was formed with three full time staff members. The group not only ensures compliance with FDAAA 2007, it also acts as a resource for study teams providing hands-on support, reporting, training, and ongoing education. Intensive resourcing for results reporting has been crucial for success. Due to implementation of the institutional policy and creation of centralized resources, compliance with FDAAA 2007 has increased dramatically at Duke Medicine for both registration and results reporting. A consistent centralized approach has enabled success in the face of changing agency rules and new legislation.

Recommendations from the Investigational New Drug/Investigational Device Exemption Task Force of the clInical and Translational Science Award Consortium: developing and implementing a sponsor-investigators training program.

OBJECTIVE: The objective of this study was to provide recommendations for provision of training for sponsor and investigators at Academic Health Centers. BACKGROUND: A subgroup of the Investigational New Drug/Investigational Device Exemption (IND/IDE) Task Force of the Clinical and Translational Science Award (CTSA) program Regulatory Knowledge Key Function Committee was assembled to specifically address how clinical investigators who hold an IND/IDE and thus assume the role of sponsor-investigators are adequately trained to meet the additional regulatory requirements of this role. METHODS: The participants who developed the recommendations were representatives of institutions with IND/IDE support programs. Through an informal survey, the task force determined that a variety and mix of models are used to provide support for IND/IDE holders within CTSA institutions. In addition, a CTSA consortium-wide resources survey was used. The participants worked from the models and survey results to develop consensus recommendations to address institutional support, training content, and implementation. RECOMMENDATIONS: The CTSA IND/IDE Task Force recommendations are as follows: (1) Institutions should assess the scope of Food and Drug Administration-regulated research, perform a needs analysis, and provide resources to implement a suitable training program; (2) The model of training program should be tailored to each institution; (3) The training should specifically address the unique role of sponsor-investigators, and the effectiveness of training should be evaluated regularly by methods that fit the model adopted by the institution; and (4) Institutional leadership should mandate sponsor-investigator training and effectively communicate the necessity and availability of training.

Isolation of SOS constitutive mutants of Escherichia coli.

The bacterial SOS regulon is strongly induced in response to DNA damage from exogenous agents such as UV radiation and nalidixic acid. However, certain mutants with defects in DNA replication, recombination, or repair exhibit a partially constitutive SOS response. These mutants presumably suffer frequent replication fork failure, or perhaps they have difficulty rescuing forks that failed due to endogenous sources of DNA damage. In an effort to understand more clearly the endogenous sources of DNA damage and the nature of replication fork failure and rescue, we undertook a systematic screen for Escherichia coli mutants that constitutively express the SOS regulon. We identified mutant strains with transposon insertions in 42 genes that caused increased expression from a dinD1::lacZ reporter construct. Most of these also displayed significant increases in basal levels of RecA protein, confirming an effect on the SOS system. As expected, this collection includes genes, such as lexA, dam, rep, xerCD, recG, and polA, which have previously been shown to cause an SOS constitutive phenotype when inactivated. The collection also includes 28 genes or open reading frames that were not previously identified as SOS constitutive, including dcd, ftsE, ftsX, purF, tdcE, and tynA. Further study of these SOS constitutive mutants should be useful in understanding the multiple causes of endogenous DNA damage. This study also provides a quantitative comparison of the extent of SOS expression caused by inactivation of many different genes in a common genetic background.

A unique type II topoisomerase mutant that is hypersensitive to a broad range of cleavage-inducing antitumor agents.

Bacteriophage T4 provides a useful model system for dissecting the mechanism of action of antitumor agents that target type II DNA topoisomerases. Many of these inhibitors act by trapping the cleavage complex, a covalent complex of enzyme and broken DNA. Previous analysis showed that a drug-resistant T4 mutant harbored two amino acid substitutions (S79F, G269V) in topoisomerase subunit gp52. Surprisingly, the single amino acid substitution, G269V, was shown to confer hypersensitivity in vivo to m-AMSA and oxolinic acid [Freudenreich, C. H., et al. (1998) Cancer Res. 58, 1260-1267]. We purified this G269V mutant enzyme and found it to be hypersensitive to a number of cleavage-inducing inhibitors including m-AMSA, VP-16, mitoxantrone, ellipticine, and oxolinic acid. While the mutant enzyme did not exhibit altered DNA cleavage site specificity compared to the wild-type enzyme, it did display an apparent 10-fold increase in drug-independent DNA cleavage. This suggests a novel mechanism of altered drug sensitivity in which the enzyme equilibrium has been shifted to favor the cleavage complex, resulting in an increase in the concentration of cleavage intermediates available to inhibitors. Mutations that alter drug sensitivities tend to cluster within two specific regions of all type II topoisomerases. Residue G269 of gp52 lies outside of these regions, and it is therefore not surprising that G269V leads to a unique mechanism of drug hypersensitivity. We believe that this mutant defines a new category of type II topoisomerase mutants, namely, those that are hypersensitive to all inhibitors that stabilize the cleavage complex.