Source: www.newswise.com
Author: press release

Chemotherapy—as any cancer patient will tell you—is not for the faint of heart, but it can kill many forms of cancer. Some form of chemotherapy, originally discovered as a cancer treatment almost seventy years ago, is still routinely prescribed for most types of the disease. The treatment works by targeting fast-growing cells, like those typically found in rapidly growing tumors. But while chemotherapy can shrink tumors, they often grow back and become resistant, or refractory to chemotherapy.

To combat this resistance, chemotherapy is now often used in combination with other treatments that have different mechanisms for attacking and killing cancer cells. But doctors must be cautious when combining treatments to ensure that the regimen does not become too toxic for patients to tolerate. The goal is to introduce drugs that can be used synergistically with chemotherapy to not only extend life, but to provide cancer patients with good quality of life while undergoing treatment.

One such complimentary drug may be Reolysin®, now being developed from the naturally occurring reovirus, by Oncolytics Biotech Inc. The reovirus preferentially replicates in cancer cells with an activated RAS pathway, while sparing normal cells. Approximately two thirds of all cancers have an activated RAS pathway, including most metastatic disease. Viral replication within cancer cells causes them to burst open, releasing more virus to infect other cells.

Reolysin is demonstrating impressive results in clinical trials on its own, but particularly in combination with certain chemotherapeutics. Recently, Oncolytics announced positive results from three combination Reolysin and chemotherapy trials.

Progress in Head and Neck Cancers
At this year’s Fifth International Meeting on Replicating Oncolytic Virus Therapeutics, in Banff, Alberta, interim clinical results were presented from a Phase I/II U.K. trial of Reolysin combined with paclitaxel/carboplatin for patients with advanced cancers.

Fifteen head and neck cancer patients have been treated in the Phase I/II trial so far. All but one patient had prior platinum treatment. Of 12 patients evaluable for clinical response, five have experienced Partial Responses (PR) and four have experienced Stable Disease (SD) ranging from two to six months. For patients who have been followed for at least six months since their initial treatment, the median progression-free survival (PFS) is currently six months, while the overall survival is currently seven months.

The literature suggests that platinum refractory patients typically have a progression-free survival of approximately two months and a median survival ranging from 4.5 to 6.5 months. While that means Oncolytics’ figures compare very favorably to date, the overall survival figure in Oncolytics’ trial may in fact improve as many of the patients are still alive.

“In patients previously treated with platinum agents, where the response rate (PR and Complete Response (CR)) is generally in the 3-10% range, to see a response rate of 42% and a 75% clinical benefit rate (SD, PR, and CR) is very dramatic,” said Dr. Mettinger.

These results led Oncolytics to announce that its first pivotal (Phase III) trial will use the same treatment combination in head and neck cancer patients who have failed traditional platinum-based therapies. The trial is expected to get underway this year.

Breaking Down Solid Tumors
Oncolytics also announced very positive clinical results from its U.K. combination Reolysin and docetaxel clinical trial for patients with advanced cancers at the Banff meeting.

Patients in the trial included those who had been diagnosed with advanced or metastatic solid tumors that are refractory (have not responded) to standard therapy or for which no curative standard therapy exists. Twenty-four patients were treated in the trial, with 17 evaluable for tumor response. Fifteen of the 17 evaluable patients experienced Stable Disease (SD) or better, including five patients who experienced minor and Partial Responses (PR), giving a clinical benefit rate (SD + PR + Complete Response (CR)) of 88%.

“Heavily pretreated patients are the most difficult to treat,” said Dr. Karl Mettinger, Chief Medical Officer for Oncolytics. “It is very encouraging to observe such a robust response rate, including a significant objective tumor response in this group.”

A third clinical trial using Reolysin in combination with gemcitabine (Gemzar®) for advanced cancer patients is also demonstrating anti-tumor activity.

Of the ten patients evaluable for response in the trial, two patients (breast and nasopharyngeal) had partial responses (PRs) and five patients had SD (stable disease) for four to eight cycles, for a total disease control rate (CR (Complete Response) +PR +SD) of 70%.