Companion diagnostics are medical tests used to determine which patients are most likely to benefit from using a drug and which patients may not benefit. Companion diagnostics are an indispensable part of personalized medicine and will continue to increase in number and application as pharmaceutical companies, including Astellas, seek to improve the efficacy and safety of therapies. Companion diagnostics are not new to the industry, but their importance has grown in recent years in line with a greater ability to understand the personalized molecular nuances of different diseases.

To find out more about how Astellas is using companion diagnostics, we turned to Joe Fleishaker, senior vice president, Clinical Pharmacology and Exploratory Development and Jason Hill, director, Oncology Biomarkers. Read the interview below.

Q: Can you tell us a little bit about companion diagnostics and how they are used in the industry; and, at Astellas?

Companion diagnostics, quite simply, are used to assess which patients are most likely to benefit from a specific product or treatment.  In the pharmaceutical industry, they are being used predominantly in oncology where they have the most application as the knowledge of tumor molecular biology has expanded most rapidly. Astellas is working on developing companion diagnostics within our oncology pipeline most notably for the A2215 (gilteritinib) program.

Q: How are companion diagnostics changing healthcare and what’s the ultimate patient benefit?

Companion diagnostics are incredibly important and help us to better identify appropriate patients who may have the best chance at responding to certain treatments. Such capabilities are leading to a revolution in cancer treatment. For example, there are genetic mutations of various tumor types, which could affect the efficacy of certain medicines. Companion diagnostics are helping us to detect these mutations easily and quickly. This has enabled us to develop medications that target these individual mutations, leading to treatments that are more effective than traditional chemotherapy in these cancer patients.

Q: Do we develop our own companion diagnostics or partner, in-license or acquire them?

Tumor biology is evolving rapidly, along with the technology being used for genetic analysis and diagnostics. Astellas is partnering with companies that have and maintain state-of-the-art analytical capabilities and expertise in companion diagnostic regulatory pathways that can be applied to our development programs.

Q: How effective are companion diagnostics and what results have we seen from using them?

In our A2215 program, we used a companion diagnostic test to look at FLT3 mutation status in patients who participated in our Phase I/II studies and used the companion diagnostic test to focus our Phase III studies on patients with FLT3 mutations. Similarly, in our A8273 program, we are using a companion diagnostic to enroll patients with epidermal growth factor receptor (EGFR) mutations in our pivotal study.