New, promising immunotherapy

Mesothelioma is diagnosed in about 3000 patients in the USA each year. For decades, only academic scientists and clinicians focused on finding effective treatments for mesothelioma. For rare diseases like mesothelioma, the US Food and Drug Administration (FDA) decided to provide incentives to companies that develop products for treatment of rare diseases through a program known as the Orphan Drug Designation program.

Recently, two new drugs were granted orphan drug status for the treatment of mesothelioma: AstraZeneca’s tremelimumab and Aduro Biotech’s CRS-207.

The need for orphan drug status

An orphan disease affects less than 200,000 patients at any given time, as defined by the FDA in 1983. However, nearly 30 million US residents have one of the 6000 to 7000 diseases classified as an orphan disease.1 To encourage investment, the FDA began the Orphan Drug Designation program in 1983. It grants incentives to companies that develop products for orphan diseases. The FDA gives orphan drug status to those products and provides a set of incentives.

The program is working. Before the program (1973 to 1983), only 10 products for all diseases with small markets were approved. In contrast, 40 products have been approved for orphan diseases in the subsequent decades.

Promising immunotherapy therapy for mesothelioma: CRS-207

Recently, an immunotherapy treatment option from immuno-oncology company Aduro Biotech called CRS-207 showed promise in treatment of mesothelioma patients in the phase I study: One of five patients showed stable disease after 1 immunization. This mesothelioma patient had overall survival greater than 29 months (conclusion of the study).2

CRS-207 vaccination induced immune responses in those cancer patients who lived longer.4 The cancer types included pancreatic ductal adenocarcinoma, non-small cell lung cancer, and mesothelioma.

Orphan drug status granted to CRS-207

At the end of March, the company announced that the FDA granted orphan drug status to CRS-207 for treatment of mesothelioma. This designation gives the company some grant funds to help defray costs of development and some tax credits.

What is CRS-207

Our bodies fight most infections very well. Sometimes, our immune system misses cancer cells and the cancer cells continue to grow. CRS-207 highjacks a bacteria that is attenuated (made thin or weak in order to increase its strength for a new job) in humans and makes it express a protein found in cancer cells (mesothelin).

Vaccination with CRS-207 stimulates the immune system of about 90% of people with mesothelioma to induce a strong immune response to the cancer, sufficient for inducing stable disease or partial response.

Most mesothelioma patients responded to CRS-207 therapy

In Oct, 2014, Aduro Biotech released preliminary results: 15 of 16 mesothelioma patients (94%) responded to the therapy.Twelve of 16 patients (75%) had partial responses and 3 of 16 patients had stable disease.

Now, the trial has expanded to 40 patients. Additional patients will be screened and enrolled in 2015, likely filling the group.

“We believe the combination of CRS-207 together with chemotherapy may offer the promise of a potential new therapeutic regimen for patients suffering from mesothelioma. Importantly, we plan to report additional data from the ongoing Phase 1b study later this year” stated Dirk Brockstedt, Ph.D., senior vice president of research and development at Aduro Biotech.

We’ll keep an eye on the progress of this promising therapy and update you as news is released.