Psiron puts back cancer trial results

Sydney oncology therapy developer Psiron (ASX:PSX) has announced a delay in reporting the results of its first phase I clinical trial of its cancer-slaying CVA 21 viral therapy in melanoma patients because of delays in access to supplies of the virus.

Psiron was due to report the result this month, but today told the market it now expects to report later this year, subject to recruiting the required number of late-stage melanoma patients.

The company also announced it has switched from producing the virus in cancerous cells -- the new virions are harvested and purified when they kill the host cells -- to using a new, non-cancer cell line.

CEO Julie Nutting said the switch to using healthy cells recognised the fact that that a patient being treated for prostate cancer, for example, might not be comfortable knowing the virus had been produced in melanoma cells. She said the treatment was essentially sterile, and there was no additional risk related to the type of cell uses to grow the viruses.

Psiron's CVA 21 viral therapy employs Cocksackie Virus A 21, which, when injected into solid tumours, causes their cancerous cells to lyse, or undergo apoptosis -- programmed cell death.

Nutting said the mechanism that induces lysis and apoptosis is not well understood, but is thought to be due to the infectious particles disrupting the cancer cell's membranes.

Psiron is preparing documentation for ethics committee reviews of two more phase I clinical trials. The first will use of CVA 21 grown in the new cell line in patients with solid tumours, and is scheduled for review in January next year.

The company is also preparing to apply for ethics approval for a phase I trial of its Echo 1 virus in patients with prostate or ovarian cancer -- again using virus grown in the new cell line.

Psiron is moving to produce CVA 21 for the second trial, to a "GMP-like" standard that will allow doctors to administer it to volunteers in accordance with Therapeutic Goods Administration requirements.

Significant result

Earlier this month, Psiron announced a "highly significant" result from a three-armed phase II trial of its Sorafin-AD therapy for mild to moderate atopic dermatitis (eczema) in adult volunteers.

Nuttall said her company had expected that the announcement would be duly listed by the ASX under its new reporting guidelines, due to its price-sensitive nature.

Surprisingly, the ASX had not done so. Nutting said that when queried the ASX, she had received an apology that the price-sensitive nature of the announcement had been missed -- apparently because of the company's statement that the report had yet to be finalised.

"We meant only that the relevant officers still had to sign off on the report -- but that wasn't going to change the results," she said.

When she asked the ASX officer who was responsible for judging whether a biotechnology company announcement was potentially price-sensitive, she had been told nobody had such expertise.

"Given that the ASX's new reporting guidelines for biotech companies demand a very high standard of disclosure, it becomes double jeopardy if they don't even understand what you write," she said.

"I'm not trying to give the ASX a hard time, I'm trying to highlight an issue. But we're keen to out-license this product, and providing a very full description of the results, and having it pass the ASX's reporting guidelines, is a great way of communicating it to the market.

"But if it's not judged to be price-sensitive, it's of no benefit to the company."

Nutting said the announcement in question concerned a trial of Sorafin, a topical ointment for eczema. The ointment consists of microparticles of gold, mixed with the steroid monetasone -- the latter is present at less half the concentration of a normal, market strength steroid treatment for eczema.

The much lower concentration of the steroid was due to the synergistic effect of the gold, which is well known for its immunomodulatory properties. "There's a large body of evidence for the safety of gold, and we're showing almost undetectable levels of gold absorption," she said.

Researchers had struggled to recruit enough volunteers to the trial, and the company had been pessimistic that it would detect a statistically significant result. Yet the result, compared against placebo, had been highly significant.

"At less than half the strength of the steroid, it would produce fewer of the typical side-effects associated with steroids, so it could potentially be used for a longer term," Nutting said.

The trial was conducted in adult volunteers. Nutting said that the reduced dose held out the promise that the therapy could be safely used in children, who tended to suffer more severe eczema.