Recommendations for Regulating the Environmental Risk of Shedding for Gene Therapy and Oncolytic Viruses in Canada.

Canadian academic and industry stakeholders are concerned about the inclusion of "virus-like particles or sub-viral particles" in the definition of New Substances Notification Regulations for Organisms (NSNR(O)) which impacts clinical cell and gene therapy and commercialization. The requirement of an independent 120 days Environment and Climate Change Canada (ECCC) review preceding a Health Canada review on quality and environmental concerns places an additional burden on Sponsors submitting clinical trial applications (CTA) and/or New Drug Submissions (NDS). A workshop initiated by CellCAN and BIOTECanada with participants from Environment and Climate Change Canada, Health Canada, the Public Health Agency of Canada and Innovation, Science and Economic Development (Ottawa, March 19, 2018) with invited stakeholders discussed approaches to streamline the environmental review process. The following main recommendations were the focus of the workshop: A regulatory policy to clarify Canadian Environmental Protection Act (CEPA)'s definition of "living organism." This is currently defined as "a substance that is an animate product of biotechnology." A regulatory policy could potentially exempt "human cells touched by biotechnology for use in human medicinal products" from this definition to clarify any unintended overreach of CEPA, particularly as it applies to non-genetically modified cell therapies.A guidance document to better interpret NSNR(O) Schedule 1 requirements by CTA/NDS sponsors to satisfy the environmental review process.An amendment at the level of regulations, to the NSNR (O) to create a deferment to postpone environmental assessment of micro-organisms used in the manufacturing during investigational clinical trials (pre-market stage). The regulations would apply at the time of market authorization evaluation and review, when sufficient clinical data on vector shedding has been collected, as part of the investigational clinical trials.Amendment to Schedule 4 of the CEPA to include the Food and Drugs Act and Regulations (Food and Drugs Act /FDR) as an exclusion to the application of CEPA. This would remove the current dual regulation of cell and gene therapies by both CEPA and Food and Drugs Act /FDR. These recommendations and other options were discussed at the workshop. These recommendations if adopted will significantly streamline the current regulatory burden and harmonize environmental assessment requirements with other jurisdictions.

Cellular and antitumor activity of a new diethylene glycol benzoporphyrin derivative (lemuteporfin).

A newly synthesized diethylene glycol functionalized chlorin-type photosensitizer, lemuteporfin, was characterized for use in photodynamic therapy (PDT) in a panel of in vitro and in vivo test systems. The photosensitizer was highly potent, killing cells at low nanomolar concentrations upon exposure to activating light. The cellular uptake of lemuteporfin was rapid, with maximum levels reached within 20 min. Mitogen-activated lymphoid cells accumulated more of the lemuteporfin than their quiescent equivalents, supporting selectivity. Photosensitizer fluorescence in the skin increased rapidly within the first few minutes following intravenous administration to mice, then decreased over the next 24 h. Skin photosensitivity reactions indicated rapid clearance of the photosensitizer. Intravenous doses as low as 1.4 micromol/kg combined with exposure to 50 J/cm2 red light suppressed tumor growth in a mouse model. In conclusion, this new benzoporphyrin was found to be an effective photosensitizer, showing rapid uptake and clearance both in vitro and in vivo. This rapid photosensitization of tumors could be useful in therapies requiring a potent, rapidly accumulating photosensitizer, while minimizing the potential for skin photosensitivity reactions to sunlight following treatment.

Lipid-derivatized poly(ethylene glycol) micellar formulations of benzoporphyrin derivatives.

In this paper, we describe the development of micellar formulations for increasing the solubility of lipophilic benzoporphyrins. Using a simple procedure that is readily adaptable for large-scale manufacturing, both A-ring (1) and B-ring isomers (2) of benzoporphyrins could be readily formulated, at concentrations up to 1-2 mg/ml, into small micelles (<20 nm in diameter) of methoxypoly(ethylene glycol) (M(r) 2000) covalently attached to the lipid anchor distearoylphosphatidylethanolamine (mPEG-DSPE). The formulations spontaneously formed upon hydration of a thin film containing mPEG-lipid and photosensitizer and were stable upon storage at 4 degrees C for at least 1 month. Self-association of the B-ring benzoporphyrin isomer in micelles could be efficiently inhibited by either increasing the molar ratio of mPEG(2000)-DSPE to benzoporphyrin or by increasing the pH of the preparation to pH 8.5. The formulation could be freeze-dried and stored indefinitely in the lyophilized form, with restoration of the original properties upon reconstitution. In vivo, the A-ring benzoporphyrin, verteporfin, had higher levels of delivery and greater tumor control in mice than the B-ring derivative when formulated in mPEG(2000)-DSPE micelles and administered intravenously. mPEG(2000)-DSPE micellar formulations also showed tumor control when administered by a single intratumoral injection followed by light irradiation to the tumor within 45-60 min after drug administration. PEG-containing micellar formulations may be a promising delivery system for benzoporphyrin monoesters for clinical applications.