FDA Greenlights Bayer-Loxo’s Vitrakvi

05.12.2018 -

A new type of cancer treatment developed by a partnership of Bayer with biotech partner Loxo Oncology has won approval from the US Food and Drug Administration (FDA). Vitrakvi is recommended for patients whose tumors feature a neurotrophic receptor tyrosine kinase (TRK) gene fusion.

The difference between TRK inhibitors and traditional oncology drugs is that the drugs do not target tumors in a particular location but cancers throughout the body that feature a specific biomarker. 

The launch of Vitrakvi, said FDA Commissioner Scott Gottlieb, “marks another step in an important shift toward treating cancers based on their tumor genetics rather than their site of origin in the body. Its approval reflects advances in the use of biomarkers to guide drug development and the more targeted delivery of medicine.”

Analysts have calculated peak sales for the drug ranging from $700 million to $1 billion up to 2030. 

The oral version of Vitrakvi costs $32,800 a month before discounts, according to a Loxo Oncology filing with the US Securities and Exchange Commission (SEC), nearly $400,000 per year.

Apart from its high price tag, reports say the companies may encounter difficulty in finding the right patients, as this requires genetic testing procedures not yet routine.

Bayer has taken on the task of working with prescribing oncologists while Loxo focuses on interfacing with lab directors and pathologists to raise awareness around tumor genomic profiling

The German group, now fully focused on life sciences, entered the TRK inhibitor partnership with Loxo in 2017 with a $400 million upfront payment – the deal also features milestones and royalties.

The German group is investing an additional $1 billion or more in Loxo’s tropomyosin receptor kinase (TRK) inhibitor franchise, with the hope of developing other new candidates.

Under the terms of its agreement with the biotech, Bayer has responsibility for global commercialization of the drug that in recent test was shown to produce response rates ranging from 75% to 81%. 

Vitrakvi is the second drug to win FDA approval based on biomarkers. In May 2017, Merck’s Keytruda received the regulator’s nod treat microsatellite instability-high cancer in any part of the body.

Roche launches Ignyta TRK diagnostic

Switzerland’s Roche meanwhile has launched a new automated in vitro diagnostic to detect tropomyosin receptor kinase proteins in cancer, which it hopes will have potential use in a range of solid tumor types and site-agnostic targeted therapies.

The Ventana pan-TRK immunohistochemistry assay identifies wild-type and chimeric fusion proteins while measuring the prevalence of TRK in tumor tissue.

“As the first test of its kind, the Ventana pan-TRK (EPR17341) Assay provides an important new tool to help us better understand the role of TRK protein expression, particularly fusions in cancer,” said Jill German, head of Roche Tissue Diagnostics.

TRK-fusion proteins have been identified in more than 30 common solid tumors, including lung, thyroid and sarcoma. While wild-type protein expression is generally low, it can be substantial in some neuroendocrine tumors, according to reports in pharmaceutical journals.

In late 2017, Roche bought San Diego, California-based biotech Ignyta for $1.7 billion in cash, gaining access to the company’s TRK inhibitor entrectinib, aimed at tumors with ROS1 or NTRK fusion mutations.