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Bowel Cancer Has Been Targeted For An Alternate Treatment

Chemotherapy treatment for people who have advanced bowel cancer and a particular genetic
mutation is commonly ineffective. A combination of three different drugs could be the key to
improved treatment.
The outlook for people with standard bowel cancer — also known as colorectal cancer — and
those with an advanced form of the disease can differ greatly.
While more than half of the former tend to survive bowel cancer for 10 or more years, the
outlook for the latter can be just a few months if cancer involves a specific gene mutation.
The BRAF gene is responsible for producing a protein that transmits signals and supports cell
growth. But a particular change to this gene — the BRAF V600E mutation — can speed up the
spread and growth of certain cancer cells.
Up to 15% of metastatic colorectal cancer (mCRC) patients have the BRAF V600E mutation.
Treating this form of cancer is difficult as it can be aggressive and tends not to respond to
combination treatments involving chemotherapy.
Now a new study has tested a combination of targeted therapies without chemotherapy.
Researchers call this the BEACON CRC Phase III trial.
Their study appears in the Annals of Oncology and featured at the ESMO World Congress on
Gastrointestinal Cancer 2019.
A mixture of three drugs — two targeting the cancer cells and one inhibiting the BRAF gene —
was analyzed on a number of individuals who had not responded to one or two previous
treatment regimes.
There were 665 participants in total. Researchers gave some all three drugs: encorafenib,
cetuximab, and binimetinib. Others had a double therapy of BRAF inhibitor encorafenib and
cancer-treating cetuximab.
A third group received a choice of the chemotherapy drug irinotecan or folinic acid, fluorouracil,
and irinotecan (FOLFIRI) and cetuximab.
Colorectal cancer does not respond to BRAF therapy alone because tumor cells adapt through
other mechanisms after initial treatment," explains Dr. Scott Kopetz, study author from the
University of Texas MD Anderson Cancer Center in Houston.
With this triple targeted therapy, we are using a very scientifically logical combination to inhibit
BRAF and these other mechanisms."
The focus was on triple therapy, and this proved to be the most successful option. While standard
therapy gave a general survival rate of 5.4 months, the three-drug combination provided a
the median survival rate of 9 months.

The response rate showed even greater improvement at 26% for the triple therapy versus just 2%
for the standard regime.
The researchers did not compare the triple and double therapies, but the two-drug combination
gave a general survival rate of 8.4 months.
Dr. Kopetz describes the findings as very exciting because of we' ve been trying to target BRAF-
mutant colorectal cancer for many years."
Hopefully, this will soon lead to increased access to this treatment for patients where there is
currently such a large unmet need."
Although future studies will need to look at whether double or triple therapy is best for
individuals, researchers believe that the three-drug treatment should replace chemotherapy for
those with a BRAF mutation.
The fact that we can give this targeted combination without the need for chemotherapy is very
good news for patients, not least because of the side effects that they typically experience with
chemotherapy," notes study co-author and professor Andres Cervantes from the Biomedical
Research Institute INCLIVA at the University of Valencia, Spain.
It is also, therefore, essential that patients are routinely tested" for the mutation.
Prof. Cervantes adds that, for the time being, they should restrict targeted therapy to those
individuals treated in the BEACON CRC trial who have progressed after one or two earlier lines
of chemotherapy. However, it is important that we investigate its use in other settings where
more patients with BRAF mutations may also benefit, including those with less advanced
metastatic disease and possibly in the adjuvant setting after primary surgery with curative
intent."