FDA approves Loxo Oncology’s larotrectinib Vitrakvi

A
tray containing cancer cells sits on an optical microscope in the
Nanomedicine Lab at UCL’s School of Pharmacy in
London.
REUTERS/Suzanne
Plunkett

• The FDA just approved a new cancer treatment in an
  unconventional way: not by tumor type, but rather by the genetic
  mutation the drug targets. 
• The drug, Vitrakvi, was developed by Loxo
  Oncology in partnership with pharma giant Bayer. 
• It’s only the second time the FDA has approved a cancer
  drug’s use based on a certain mutation rather than a particular
  tumor type. 

The Food and Drug Administration just took an unconventional
approach to approving a new cancer drug. 

The drug, Vitrakvi, was developed by Loxo Oncology. It’s
the company’s first drug to get approved.

Loxo’s approach is to develop drugs that act on cancerous
genetic mutations rather than the type of cancer a person has.
For example, Vitrakvi, has been
tested in patients with lung, colon, breast and thyroid
cancer among others.

In 2017, the drugmaker struck a $1.5 billion deal with
pharma giant Bayer to commercialize and develop two of Loxo’s
drugs, including Vitrakvi. 

Targeting a genetic mutation instead of cancer type

Building a treatment that’s specific to a genetic mutation
is a new approach to treating cancer. Most companies develop
treatments for specific types of cancer, like lung cancer or
melanoma, and seek approval just for that one kind of tumor at
first, before setting up more trials to see how the drug does in
other types of cancer.

Scientists have seen genetic patterns across
cancer types for years, but the topic
started attracting more attention in 2013
after the
discovery that endometrial cancer was
genetically similar to forms of ovarian and breast cancer.

In May 2017, the
FDA approved a drug based on genetics
rather than tissue type for the first time, paving the way for
others including Loxo.

Loxo’s drug works in cancer patients with a mutation called a
“TRK gene fusion.”

Loxo Chief Business Officer Jake Van
Naarde told
Business Insider in 2016 that the company
estimates that there’s anywhere from 1,500 to 5,000 new cases of
late-stage cancers that have the TRK fusion a year.

The company has seen
promising results in its human trials. In a recent
presentation at the European Society for Medical Oncology, Loxo
said that out of 109 patients, 81% had an overall response rate,
meaning their tumors shrank. In 17% of the cases, the patients
had a complete response, meaning their tumors went away
entirely. 

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