Gene Therapy for Intractable Cancer Pain

By Bernard M. Abrams, MD

A new study reported in Pain Medicine from Diamyd, the University of Michigan and Ann Arbor VA Healthcare System, discuss the first human trial of gene therapy for chronic pain, a phase 1 study of a nonreplicating herpes simplex virus (HSV)-based vector engineered to express preproenkephalin in patients with intractable pain from cancer.

The rationale and previous supporting data from animal experiments are discussed. Enrolling subjects in December 2008, the authors began with intractable cancer patients with pain.

The authors admit a critical limitation in the use of standard oral drugs to treat severe chronic pain, citing that their actions are not limited to the neural pathways involved in the transmission of pain-related information.

Transduction of DRG neurons by subcutaneous inoculation of the HSV-based vector expressing preproenkephalin reversed nocisponsive behavioral responses to heat, cold and mechanical pressure characteristics of painful diabetic peripheral neuropathy.

While this approach must be regarded as preliminary, it offers the exciting possibility of treatment of neuropathic pain while avoiding such common problems as opioids tolerance and side effects.

Darren Wolfe, PhD,* James Wechuck, PhD,* David Krisky, MD, PhD,* Marina Mata, MD, and David J. Fink, MD, PAIN MEDICINE, Volume 10 • Number 7 • 2009, 1325-1330.