Chinese scientists pioneer human genetic editing

CHENGDU -- Chinese scientists will perform the world's first genetic editing trial on humans this month in an attempt to find a cure for lung cancer.

A group of oncologist at the West China Hospital of Sichuan University, Chengdu, will inject patients with cells that have been modified using the CRISPR-Cas9 gene-editing technique.

CRISPR, short for clustered regularly interspaced short palindromic repeats, was named "2015 Breakthrough of the Year" by US journal Science. It allows scientists to selectively edit genome parts and replace them with new DNA stretches. Cas9 is an enzyme that can edit DNA, allowing the alteration of genetic patterns by genome modification. CRISPR is a collection of DNA sequences that direct Cas9 where to cut and paste.

Lu You, director of the hospital's thoracic oncology department and the leader of the trial, said his team was formed at the end of last year and the trial received ethical approval from the hospital's review board on July 6.

"We plan to select ten volunteers, all advanced lung cancer patients who have undergone chemotherapy, radiation therapy and other types of treatment. We received a lot of applications and are now busy screening and drawing up our final selection list," he said.

The editing therapy treatment periods will last from eight weeks to three months. The whole trial could last over a year, he said.

Doctors will extract T cells, a type of immune cell, from the patient's blood and then knock out the gene that encodes the PD-1 protein, which normally limits the cell's capacity to launch an immune response. The edited cells will be multiplied in the lab before being reintroduced to the patients. This process will hopefully kick start the T cells to launch an attack on the tumor cells.

"It is like building a cancer-fighting army outside the patient body," Lu said.

However, the T cells might also attack normal tissue, Lu said, this first phase of the trial aims to determine whether the approach is safe.

"The top priority is safety. We will closely monitor the patients," he said. "The clinical trial is just the beginning, there are a lot of uncertainties, which will require further research."

Lu believed that CRISPR-Cas9 technology has the potential to revolutionize the treatment of blood diseases, tumors and other genetic diseases.

The mortality rate of lung cancer patients is high.

"This is why we chose cancer patients for the initial trial. Should the approach prove safe, we will consider expanding our research," Lu said.