The discovery, reported in the journal Nature Immunology, suggests
doctors and drug developers will need to get smarter in zeroing in
on those people who stand to benefit from the expensive new drugs,
which are revolutionizing cancer care.
Drugs such as Merck & Co's Keytruda, Bristol-Myers Squibb's Opdivo,
Roche's Tecentriq and AstraZeneca's Imfinzi can boost the immune
system's ability to fight tumors, but they only work for some
The current widely used benchmark when giving cancer immunotherapy
is a protein called PDL-1. However, many experts view PDL-1 as a
"blunt instrument", since it does not match precisely to drug
response, leading to the consideration of other measures, such as
the level of mutation in tumors.
The latest research adds a further twist by highlighting the role of
so-called tissue-resident memory T-cells.
Researchers from the University of Southampton and La Jolla
Institute for Allergy and Immunology found that lung cancer patients
with lots of this cell type in their tumors were 34 percent less
likely to die than others.
"Having made the first baby steps with PDL-1 testing, we need to be
smarter by using new tests," said Christian Ottensmeier, a Cancer
Research UK scientist who worked on the study.
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"PDL-1 testing is a little bit like
saying 'you've got a Ferrari because it is red'. Many Ferraris are
red and many tumors that are PDL-1 positive will respond to
immunotherapy, but on its own that is not sufficient."
Ottensmeier and colleagues now plan
further clinical trials to see how well their biological predictor
can pick out patients who will benefit from taking Opdivo.
Industry analysts expect the new generation of cancer immunotherapy
drugs to generate tens of billions of dollars in annual sales by
early next decade, with lung cancer the biggest single market.
(Reporting by Ben Hirschler, editing by Louise Heavens)
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