Source: statesman.com
Author: Lilly Rockwell

Doctors who have used Advexin, a new head-and-neck cancer drug developed by an Austin biotechnology company, say the gene therapy that has yet to be approved by the U.S. Food and Drug Administration works, shrinking tumors in some patients that used the experimental therapy.

In a conference call with industry analysts Thursday, Introgen Therapeutics Inc. defended its clinical trial data, saying Advexin is designed to work only on patients with the right genetic profile.

Several doctors who have used the drug in clinical trials praised Advexin for successfully treating tumors, with one saying he has a patient who is now in remission after receiving Advexin for eight years.

“Advexin was found to be an effective treatment that will have important implications for patients with head-and-neck cancer,” said John Nemunaitis, a principal investigator of Introgen’s phase III study and medical director at a cancer center in Dallas.

Introgen has been developing Advexin for 14 years. The drug is designed to target the p53 tumor suppressor gene, boosting its levels in patients who don’t have mutations in the gene.

If approved, it would be used to treat patients with recurrent head-and-neck cancer. Eventually, Introgen said, the Advexin therapy could be used to treat diseases such as lung cancer.

Introgen applied for FDA approval of Advexin on June 30. It is the first gene therapy drug submitted for FDA approval. The company has asked for priority review status, which could give Introgen an answer in less than six months.

“The current therapy is really inadequate,” said Jack Roth, the inventor of Advexin and a doctor at M.D. Anderson Cancer Center. “The vast majority (of head-and-neck cancer patients) do not respond to standard therapies.”

Roth said a decrease in p53 leads to almost all cancers, not just head-and-neck cancers, which is why Advexin targets that particular gene.

But there are skeptics who question why the drug doesn’t work on all head-and-neck cancer patients, according to clinical trial data. Others question why Introgen started targeting only patients with a certain p53 profile after the phase II trial results were completed. Introgen received approval from the FDA to analyze its data by separating out patients who had the correct p53 biological markers.

Hearing the feedback from doctors helps solidify the clinical trial results, Canaccord Adams analyst Joseph Pantginis said.

“There was clearly evidence of significant activity, shrinkage and stabilization of (the tumor),” Nemunaitis said. “Many of these patients, when they go through chemotherapy it is very difficult.”

Advexin lessened the pain, improved patients’ ability to function and was less toxic than chemotherapy, Nemunaitis said. “It’s not difficult to give injections. … I was very pleased.”

Introgen isn’t disclosing how much it plans to charge for Advexin, but Pantginis said it could be priced around $20,000 for one year.

Earlier this month, Introgen disclosed it plans to reorganize its staff, laying off 20 of its 70 employees. But it plans to ramp up its manufacturing staff in preparation for possible approval of Advexin.