Myriad’s Innovation Led to Discovery of a Novel Companion Diagnostic

At Myriad, we regularly reach out to our customers in the medical and scientific communities as part of our ongoing process to understand their needs and
then work with them to identify solutions to help them achieve their goals. Six or seven years ago, I embarked on one such fact-finding mission to better
understand the specific needs of breast oncologists. I attended many medical meetings and was fortunate to speak and collaborate with many passionate
oncologists and researchers. One conversation I had, in particular, summed up a common theme I was hearing.

I was visiting a leading breast oncologist at MD Anderson Cancer Center, and I asked her what diagnostic test was on her “wish list.” She thought briefly
and responded: “I need tools to tell me which chemotherapy to give to a particular patient.” The simplicity of her needs echoed those of many oncologists
we spoke with – a need that still exists. To the present day, the choice of chemotherapy remains dictated by a balance between maximizing effectiveness and
avoiding unacceptable toxicity and side effects. It is only personalized after the fact.

Because we listened intently to our customers, we incorporated what we learned into our research. As it happens, around this timeframe our biologists and
bioinformatics group began to peer into the genomes of cancer cells using DNA array tools that were designed to interrogate single nucleotide changes in
human DNA. Our goal was to identify DNA scars that might be useful diagnostically or in predicting outcomes to chemotherapy. Ironically, the more damage
that DNA has, the easier it may be to treat.

Ultimately our fact-finding mission led our team of talented scientists to create a novel precision medicine test called Myriad myChoice, which is a
DNA-based readout of the degree to which a tumor has lost the ability to repair damaged DNA. In other words, myChoice is a quantitative test (on a
scale of 0-100) designed to identify the patients who have DNA scars and who are likely to respond to DNA-damaging drugs such as the platinum medicines and
the new class of PARP inhibitors in development at many pharmaceutical companies. Our research has shown that high HRD scores are common in ovarian and
breast cancers, but pancreatic, colon and lung tumors also can have high HRD scores.

We already have conducted multiple clinical studies in breast cancer that show the myChoice test does, in fact, predict tumor response to platinum-based
drug regimens – the higher the HRD score, the more likely the response. We’re on track to bring myChoice to the market within the next nine months to
enable doctors to make an informed and patient-centric choice for this useful class of drugs. We’re also optimistic that the new test will widen the
eventual use of PARP inhibitors beyond the patient group who have hereditary cancer-causing BRCA mutations. Our research in this area is continuing, and we
plan on presenting new data on the myChoice HRD test at several upcoming medical meetings.

The myChoice test illustrates how Myriad works collaboratively and innovates in response to our customers’ input. The world of molecular diagnostics is
changing, as evidenced by the rapid shift toward precision medicine, particularly in oncology. This shift is being driven by the needs of our customers
and their patients. While there are many drugs to treat cancer, our goal is to help physicians select the medicine that will work best for their patients
from the outset. Often, the first therapy chosen is the one that defines patient outcomes. Furthermore, precision medicine tests like myChoice promise to
reduce the time and resources spent on treatments that won’t work based on the patient’s biology – a big consideration today as the healthcare ecosystem
strives to control costs.

Jerry Lanchbury, Ph.D.

Chief Scientific Officer