Brocker.Org: A promising new cancer treatment is facing a deadly setback

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Cancer
cells are seen on a large screen connected to a microscope at the
CeBit computer fair in Hanover, Germany, March, 6,
2012.

Reuters

  • Cancer immunotherapy, or treatments that use the body’s
    own immune system, have been gaining traction over the past few
    years. 
  • That’s especially true with a group of therapies called
    “checkpoint inhibitors.”
  • But there have been some setbacks to other
    approaches, including cell therapies, with some cases turning
    deadly. 

We’re starting to get a clearer picture of some of the
consequences of cancer immunotherapy, a new area of
therapies that harness the body’s immune system to take on cancer
cells. 

The drugs have generated a lot of excitement for the
revolutionary way they treat cancer. The drugs don’t have the
same side effects as chemotherapy, and in cases
like former
US President Jimmy Carter
, people have ended up being
cancer-free.

But now, as more data comes out and newer waves of drugs get
closer to approval, that excitement is starting to get tempered
in the face of deadly side effects and failed trials. 

Facing setbacks

The first wave of these treatments are called checkpoint
inhibitors. Most people have a type of protein that stops their
immune systems from fighting the cancerous cells. These
checkpoint inhibitors block those proteins. It’s like taking
down a guard tower, allowing the body’s own immune system to
flood past a barrier, where it then gets to work killing and
clearing away the cancer cells.

Checkpoint inhibitors were first approved to treat melanoma but
have since gone on to tackle lung cancer, bladder cancer, blood
cancers, and other cancers. There are now six approved
checkpoint inhibitors

But they’re far from perfect. For one, not everyone is
responding to the drugs — for advanced stages of melanoma, the
number of people still alive after two years

was about 35%
, compared to 29.7% over the same time for
those taking chemotherapy. And sometimes new checkpoint
inhibitors under development
have failed key trials
. The drugs also tend to be expensive,
costing more than
$100,000 for a course of treatment
. And there’s even reports
that in some patients, the checkpoint
inhibitors
 could be
speeding up tumor growth
.

Now, a second wave of cancer immunotherapy is facing some
challenges. The highly personalized treatment is
called 
CAR
T-cell therapy
. Short for “chimeric antigen
receptor” T-cell therapy, the treatment takes a person’s own
cells, takes them out of the body, reengineers them, then puts
the cells back in the body where they can attack a particular
cancer cell.

But on Monday, Kite
Pharma revealed that one person had died
 while in a
clinical trial for its late-stage CAR-T therapy from cerebral
edema, a condition in which the brain swells up because of
excessive fluid in the brain. It’s not the first time these
therapies have experienced that severe side effect.

In July, another CAR-T company, Juno Therapeutics, said four
people in its
clinical trials had died
, all from cerebral edema. It’s
dampened the excitement that people once had for the
therapy. 

‘A long way to go’


cancer cells
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 T-cell therapies are “assassins,” Matt Hawryluk,
chief business officer of Gritstone Oncology, told Business
Insider.
 That makes them a really powerful weapon, he
said, but that can be good and bad depending on whether it’s
hitting the intended cancer target or accidentally affecting
other parts of the body.

Gritstone is working on another type of cancer immunotherapy
called cancer vaccines that wants to help amplify the body’s
immune system to fight off cancer cells.

Even with the deaths that have been reported, there still could
be an upside to treating some patients with the drug even if
there are deadly risks attached. 

“I feel there is a long way to go. And ultimately if in many
cases it’s curing patients, we have to take the risk and
then manage the benefits,” Roman Yelensky, chief technology
officer at Gritstone Oncology, told Business Insider. 

Kelly Page, Takeda’s vice president of strategic planning in
oncology, said this isn’t all too different from the speed bumps
the first immunotherapies (namely the checkpoint inhibitors)
experienced when they first hit the field. “They were
technologies before their time,” she said.

Researchers had a hard time monitoring how the immune system
reacted with those therapies for a while before figuring out
how to do it more safely. 

“I think some of the other modalities, whether it be CAR-Ts or
whatever, are going to go through that same thing,” Page said.
“There’s this struggle every time you bring in a new modality,
but once you figure it out, it’s fantastic.”

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