Mesothelioma Immunotherapy Enters Ring, Takes Off Gloves

An innovative vaccine plus chemotherapy delivers a one-two punch that appears potentially capable of laying mesothelioma out cold.

Not yet known is whether the treatment strategy can keep the cancer down for the count.

Still, the mesothelioma patients on whom it was tested looked a lot like champs — a crown they each might hold onto if the treatment proves out in later, more comprehensive testing.

Findings announced last month at the American Society of Clinical Oncology’s annual meeting indicated that the new vaccine made a small but encouraging difference for nearly 70 percent of the test patients.

Aduro BioTech Inc. — the company that developed the vaccine — was especially pleased because the mesothelioma treated was advanced and untreatable with surgery.

The company was also heartened that its vaccine seemed to make the chemotherapy more effective and its results last longer.

Lab-Engineered Bug Strengthens Immune System

The vaccine is named CRS-207. Aduro explained that it’s designed to strengthen the immune system of mesothelioma patients. CRS-207 enables the immune system to fight harder when it discovers that mesothelioma tumors are growing.

CRS-207 is based on a live-attenuated, double-deleted form of the monocytogene Listeria. Listeria is normally something that makes you sick.

But Aduro lab-engineered this nasty little bug so that it would trigger a strong, positive response from the immune system. The response includes a brutal desire to hunt down mesothelin and bash away at it.

If you have mesothelioma, mesothelin isn’t hard to find. It’s an antigen that mesothelioma produces in massive quantity.

Aduro said its vaccine could also work against other forms of cancer, including pancreatic, ovarian and prostate.

Process for the Mesothelioma Clinical Trial

In the mesothelioma clinical trial, Aduro found 16 suitable patients for testing. None had before undergone chemotherapy. All were beyond the point where surgery was practical.

The testing began with each patient receiving a dose of CRS-207. Two weeks later, they received one more.

Then came as many as six cycles of chemotherapy consisting of pemetrexed and cisplatin. The patients were given the chemotherapy at three-week intervals. They also received biweekly CRS-207 booster vaccinations — a total of two.

If they were clinically stable after all this they were given CRS-207 vaccinations every eight weeks as a maintenance regimen.

The results: 11 of the 16 patients were confirmed to have had what are known as “durable partial responses” to the treatment. According to the company’s scientists, that was good.

Aduro also said none of the participating patients suffered treatment-related serious adverse events or unexpected toxicities. That, too, was good, the company’s scientists indicated.

Company Plans More Mesothelioma R&D

Aduro BioTech is a private, clinical-stage biotechnology company. Most of what it does involves cancer immunotherapy research and development.

About a week before revealing the CRS-207 study results, the company announced it had entered into a $365-million agreement with another biotech company to jointly work on another application of the vaccine.

Meanwhile, Aduro is going forward with its own projects that seek to employ novel small molecules that activate the intracellular STING receptor, which is a central mediator of immune-system response.

For mesothelioma patients, Aduro’s vaccine means another contender is in the ring and looking to deliver that knockout blow against the cancer.