Evolution of a gene therapy clinical trial. From bench to bedside and back

Recommendations for nanomedicine human subjects research oversight: an evolutionary approach for an emerging field

The nanomedicine field is fast evolving toward complex, "active," and interactive formulations. Like many emerging technologies, nanomedicine raises questions of how human subjects research (HSR) should be conducted and the adequacy of current oversight, as well as how to integrate concerns over occupational, bystander, and environmental exposures. The history of oversight for HSR investigating emerging technologies is a patchwork quilt without systematic justification of when ordinary oversight for HSR is enough versus when added oversight is warranted. Nanomedicine HSR provides an occasion to think systematically about appropriate oversight, especially early in the evolution of a technology, when hazard and risk information may remain incomplete. This paper presents the consensus recommendations of a multidisciplinary, NIH-funded project group, to ensure a science-based and ethically informed approach to HSR issues in nanomedicine, and to integrate HSR analysis with analysis of occupational, bystander, and environmental concerns. We recommend creating two bodies, an interagency Human Subjects Research in Nanomedicine (HSR/N) Working Group and a Secretary's Advisory Committee on Nanomedicine (SAC/N). HSR/N and SAC/N should perform 3 primary functions: (1) analysis of the attributes and subsets of nanomedicine interventions that raise HSR challenges and current gaps in oversight; (2) providing advice to relevant agencies and institutional bodies on the HSR issues, as well as federal and federal-institutional coordination; and (3) gathering and analyzing information on HSR issues as they emerge in nanomedicine. HSR/N and SAC/N will create a home for HSR analysis and coordination in DHHS (the key agency for relevant HSR oversight), optimize federal and institutional approaches, and allow HSR review to evolve with greater knowledge about nanomedicine interventions and greater clarity about attributes of concern.

First-in-human trial participants: not a vulnerable population, but vulnerable nonetheless

The 21st-century translational science campaign could lead to an increase in first-in-human (FIH) trials. As tests of investigational interventions move from the laboratory to human research, scientists, officials, and review committees should address ongoing concerns about the ethics of FIH trials. In this article, I describe three ethical considerations relevant to all FIH trials: (1) the requirement for adequate preclinical research; (2) study design safeguards; and (3) choice of subject population. I also examine specific ethical considerations relevant to the three subject populations (healthy volunteers, seriously ill patients lacking standard treatment options, and stable patients) involved in FIH research. I recommend a variety of actions that could increase subject protection and the value of the information generated in FIH trials.

Targeted Cancer Therapy with Tumor Necrosis Factor-Alpha

Tumor necrosis factor-alpha (TNF-α), a member of the TNF superfamily, was the first cytokine to be evaluated for cancer biotherapy. However, the clinical use of TNF-α is severely limited by its toxicity. Currently, TNF-α is administered only through locoregional drug delivery systems such as isolated limb perfusion and isolated hepatic perfusion. To reduce the systemic toxicity of TNF-α, various strategies have been explored over the last several decades. This review summarizes current state-of-the-art targeted cancer therapy using TNF-α. Passive targeting, cell-based therapy, gene therapy with inducible or tissue-specific promoters, targeted polymer-DNA complexes, tumor pre-targeting, antibody-TNF-α conjugate, scFv/TNF-α fusion proteins, and peptide/TNF-α fusion proteins have all been investigated to combat cancer. Many of these agents are already in advanced clinical trials. Molecular imaging, which can significantly speed up the drug development process, and nanomedicine, which can integrate both imaging and therapeutic components, has the potential to revolutionize future cancer patient management. Cooperative efforts from scientists within multiple disciplines, as well as close partnerships among many organizations/entities, are needed to quickly translate novel TNF-α-based therapeutics into clinical investigation.

Applying models of targeted drug delivery to gene delivery

Gene delivery requires targeted delivery systems. Exploratory simulations using models of targeted drug delivery helps one assess the worthiness of such systems, and helps quantify the expected therapeutic benefits of the systems. The drug targeting index (DTI), a ratio of availabilities, is a measure of pharmacokinetic benefit of the delivery device, based on a combination of a physiologically-based pharmacokinetic model and a single pharmacodynamic E<inf>max</inf>model. Pharmacodynamic outcomes are quantified by the degree of separation between the dose-response and dose-toxicity curves (SRT). Simulations are undertaken to investigate the potential linkage of DTI and SRT, a pharmacodynamic outcome. A significant positive linear relationship is found between the DTI and SRT. The relationship can be translated into a minimum pharmacokinetic requirement that can be used to guide making decisions regarding whether or not further pursue the development of a candidate gene-delivery device as a therapeutic agent.

Cyclophosphamide allows for in vivo dose reduction of a potent oncolytic virus

The success of cancer virotherapy depends on its efficacy versus toxicity profile in human clinical trials. Progress towards clinical trials can be hampered by the relatively elevated doses of oncolytic viruses administered in animal models to achieve an anticancer effect and by the even higher doses required in humans to approximate an animal bioequivalent dose. Such elevated doses of injected viral proteins may also lead to undesirable toxicities and are also very difficult to produce in a biotechnological setting. We report that a relatively potent herpes simplex virus type 1 oncolytic virus (rQNestin34.5) produces 45% survivors at a dose of 3 x 10(4) plaque-forming units (pfu) in a 9-day-old mouse model of human glioma. Unlike our previous findings with less potent oncolytic viruses, though, the preadministration of cyclophosphamide did not enhance this survival or affect oncolytic virus tumor distribution and tumor volume. However, when oncolytic virus doses were reduced (3 x 10(3) and 3 x 10(2) pfu), cyclophosphamide significantly enhanced both animal survival and oncolytic virus tumor distribution and also reduced tumor volumes. These findings thus show that cyclophosphamide allows for dose reduction of doses of a relatively potent oncolytic virus, a finding with implications for the development of clinical trials.

Gene therapy in the clinic: whose risks?

Current experience with gene therapy for X-linked severe combined immunodeficiency disorder (X-SCID) suggests that we might now be at the point where it can be considered the 'standard of care'. This therapy carries an unquantified risk of leukaemia, raising important questions for regulators. How dangerous does a potentially curative therapy for a fatal illness need to be before we call it unsafe. How uncertain does a risk need to be for us to regard a therapy as still 'experimental'? Whose interests should prevail? Here I argue that in X-SCID it is the parents and children whom we should listen to first and foremost. How far does this patient-centred approach to licensing therapies extend? Can it be given a rational basis?

Malignant gliomas

Malignant gliomas are the most common type of primary brain tumor. Although therapy for patients with these tumors remains limited, there has been important progress recently. In this review, some of these advances are discussed, with an emphasis on targeted molecular therapies.