Infection Control for Research Studies Utilizing Oncolytic Viral and Bacterial Vectors

Background: Oncolytic viral and bacterial vectors are increasingly being studied as promising new treatments for cancer. In October 2015, the FDA approved the first genetically modified oncolytic viral therapy. However, infection control guidelines regarding the use of these agents are not well defined.

Methods: At our institution, all research protocols involving potentially contagious viral or bacterial vectors are reviewed by Infection Control. Approval by the Institutional Review Board and Institutional Biosafety Committee is contingent upon satisfactory achievement of all Infection Control requirements.

Results: Since 2013, we have reviewed 13 protocols utilizing 7 different vectors (Table 1). For all protocols, we required additional education of staff. For 12 (92.3%) protocols, we required additional infection control measures beyond those recommended in the study protocol (Table 2). No transmission events have occurred.

Conclusion: Study protocols regarding administration of oncolytic viral and bacterial vectors may not provide sufficient infection control guidance. Review by infection control experts provides additional safety.

Table 1

Agent	Description	Disease
Pexa-Vec	Modified vaccinia virus vector	Hepatocellular carcinoma
Talimogene Laherparpvec	Modified HSV-1, selective replication within tumors	Melanoma
AD-RTS-hIL-12	Replication incompetent adenovirus vector	Glioblastoma
CRS-207	Live, attenuated Listeria vector	Pancreatic adenocarcinoma
CG0070	Conditionally replicating adenovirus	Bladder carcinoma
CTL019	CD3+ T cells modified through lentiviral vector transduction	B-cell ALL, Diffuse large B-cell lymphoma
KTE-C19	CD3+ T cells modified through retroviral vector transduction	B-precursor ALL, Mantle cell lymphoma

Table 2

Required Additions to Protocols	Number of protocols (%)
Education of staff	13 (100%)
Restriction of staff due to medical conditions (e.g. pregnancy, immunocompromised status)	6 (46.2%)
Patient isolation	5 (38.5%)
Preparation, storage, transport, or disposal of drug	9 (69.2%)
Environmental cleaning	7 (53.8%)
Minimize patient exposure to others in medical center (e.g. immediate rooming, staff escort)	5 (38.5%)
Patient card or bracelet with study information	5 (38.5%)