The US Food and Drug Administration (FDA) has released a long-sought final guidance document on in vitro diagnostic (IVD) companion diagnostic (CDx) products—products intended to help guide the therapeutic use of new medicines based on a consumer's genetic characteristics.
Regulators and industry have both been touting the benefits of companion diagnostics in recent years as the products have become, in the words of FDA, "more common."
The benefits to both groups are relatively straightforward. For regulators, the use of the diagnostic tests makes it easier to determine which patients will benefit, and also decreases the chance of a drug being used off-label in untested populations or populations unlikely to benefit. For drugmakers, the use of companion diagnostics theoretically makes it easier to obtain approval by allowing regulators to see who stands to benefit from a drug, and why.
On the other hand, the need to have both a drug and device ready to be brought to market at the same time can potentially delay approvals, even as smaller and more targeted trials can allow companies to save time (and money).
FDA has already approved 18 companion diagnostic tests, Center for Devices and Radiological Health (CDRH) Director Jeffery Shuren said in a statement to the press. That includes the 2012 approval of Qiagen's Therascreen KRAS RSQ PCR Kit and Eli Lilly/Bristol-Myers Squibb's Erbitux (cetuximab), a drug intended to treat colorectal cancer in patients with KRAS gene mutations, and the 2013 approval of Roche's Cobas EGFR Mutation Test, a CDx for Astellas' NSCLC drug Tarceva (erlotinib).
On a media call, Shuren said the final guidance, In Vitro Companion Diagnostic Devices, was "generally consistent" with a 2011 draft predecessor and is primarily intended to clarify parts of the guidance that were confusing the industry.
For example, the guidance now states that, "in most circumstances, an IVD companion diagnostic device and its corresponding therapeutic product should be approved or cleared contemporaneously by FDA for the use indicated in the therapeutic product labeling." This is in order to make sure the therapeutic product can be used safely and in patients most likely to benefit, FDA explained. In cases where the drug cannot be used safely or effectively without the CDx, FDA will not approve it.
FDA will, however, approve some drugs without a CDx in certain circumstances. For example, if the therapy is intended to treat a serious or life-threatening disease, FDA "may" approve that product anyway.
FDA also notes that CDx devices must be accurate and reliable in order for patients—and regulators—to benefit from their use. "Erroneous IVD companion diagnostic device results could lead to withholding appropriate therapy or to administering inappropriate therapy," FDA explains in its guidance.
And while CDx products will be reviewed as devices, FDA clarified that it "intends to review each IVD companion diagnostic device submission within the context of, or in conjunction with, its corresponding therapeutic product." The agency will adopt a risk-based approach for each review, it clarified.
Therapeutic products will also be required to bear labeling indicating how it should be used with a CDx, FDA said.
In Vitro Companion Diagnostic Devices