‘Living drug’ to fight cancer
WHEN doctors saw the report on Bill Ludwig’s bone-marrow biopsy, they thought it was a mistake and ordered a new test. But the results came back the same: his leukaemia had been wiped out by an experimental treatment never used in humans.
“We were hoping for a little improvement,” remembers the 72-year-old retired New Jersey prison warder, who had battled the disease for a decade. He and his oncologist both broke down when she delivered the good news in 2010. “Nobody was hoping for zero cancer.”
The pioneering therapy with Ludwig and a few other adults at the University of Pennsylvania hospital paved the way for clinical trials with children. Emily Whitehead, 6, who was near death, became the first paediatric recipient in 2012. Like Ludwig, she remains cancer-free.
Such results are why the treatment is on track to become the first gene therapy approved by the Food and Drug Administration. An advisory committee will decide this week whether to recommend approval of the approach, which uses patients’ own genetically altered immune cells to fight blood cancers.
If the panel gives the nod, the agency probably will follow suit by the end of September.
That would open the latest chapter in immunotherapy, “a true living drug”, says Penn scientist Carl June, who led its development.
The CAR T-cell treatment, manufactured by the drug company Novartis, initially would be available only for the small number of children and young adults whose leukaemia doesn’t respond to standard care.
Those patients typically have a grim prognosis, but in the pivotal trial testing the therapy in almost a dozen countries, 83% of patients went into remission. A year later, two-thirds remained so.
And childhood leukaemia is just the start for a field that has attracted intense interest in academia and industry. Kite Pharma of Santa Monica, California, has applied for FDA approval for aggressive non-Hodgkin lymphoma, and a similar Novartis application is close behind.
Researchers are exploring CAR T-cell therapy’s use for multiple myeloma and chronic lymphocytic leukaemia, the disease that afflicted Ludwig. They’re also tackling a far more difficult challenge – using the therapy for solid tumours in the lungs or brain, for example.
The excitement among doctors and researchers is palpable. “We’re saving patients who three or four years ago we were at our wit’s end trying to keep alive,” said Stephen Schuster, the Penn oncologist who is leading a Novartis lymphoma study. Both the study and a Kite trial have shown the treatment can put about a third of adults with advanced disease – those who have exhausted all options – into remission.
Yet along with the enthusiasm come pressing questions about safety, cost and the complexity of the procedure.
It involves extracting white blood cells called T cells – the foot soldiers of the immune system – from a patient’s blood, freezing and sending them to Novartis’s manufacturing plant in Morris Plains, New Jersey. There, a crippled HIV fragment is used to genetically modify the T cells so they can find and attack the cancer.
The cells then are refrozen and sent back to be infused into the patient.
Once inside the body, the T-cell army multiplies astronomically.
Novartis hasn’t disclosed
We were hoping for a little improvement. Nobody was hoping for zero cancer
the price for its therapy, but analysts are predicting $300 000 (R4 million) to $600 000 for a one-time infusion. Brad Loncar, whose index fund focuses on cancer immunotherapy treatment, hopes the cost doesn’t prompt a backlash.
“This is truly pusing the envelope and at the cutting edge of science.”
The biggest concerns, however, centre on safety. The revved-up immune system becomes a potent cancer-fighting agent but also a dangerous threat to the patient. Serious side effects abound, raising concerns about broad use.
“Treating patients safely is the heart of the rollout,” said Stephan Grupp of the Children’s Hospital of Philadephia, who as director of its cancer immunotherapy programme led early pediatric studies as well as Novartis’s global trial. “The efficacy takes care of itself, but safety takes a lot of attention.”
One of the most common side effects is called cytokine release syndrome, which causes high fever and flu-like symptoms that in some cases can be so dangerous that the patient ends up in intensive care.
The other major worry is neurotoxicity, which can result in temporary confusion or potentially fatal brain swelling.
Juno Therapeutics, a biotech firm in Seattle, had to shut down one of its CAR T-cell programmes because five patients died of brain swelling. Novartis has not seen brain swelling in its trials, company officials said.
To try to ensure patient safety, Novartis isn’t planning a typical product rollout, with a drug pushed as widely and aggressively as possible. The company instead will designate 30 to 35 medical centres to administer the treatment. Many of them took part in the clinical trial, and all have received extensive training by Grupp and others.
Grupp said he and his staff learnt about the side effects of CAR T-cell therapy – and what to do about them – through terrifying experience that began five years ago with Emily Whitehead.
The young girl, who had relapsed twice on conventional treatments for acute lymphoblastic leukaemia, was in grave condition.
Grupp suggested to her parents that she become the first child to get the experimental therapy.
After the therapy, Emily’s fever soared, her blood pressure plummeted, and she ended up in a coma and on a ventilator for two weeks in the hospital’s intensive care unit. Convinced his patient would not survive another day, a frantic Grupp got rushed lab results that suggested a surge of interleukin 6 was causing her immune system to relentlessly hammer her body. Doctors decided to give Emily an immunosuppressant drug called tocilizumab.
She was dramatically better within hours. She woke up the next day, her 7th birthday. Tests showed her cancer was gone.
The approval of CAR T-cell therapy would represent the second big immunotherapy advance in less than a decade. In 2011, the FDA cleared the first agent in a new class of drugs called checkpoint inhibitors.
It has approved four more since.
There are big differences between the two approaches. The checkpoint inhibitors are targeted at solid tumours, such as advanced melanoma, lung and bladder cancer, while CAR-T cell therapy has been aimed at blood disorders. And although checkpoint inhibitors are off the shelf, with every patient getting the same drug, the other is customised to an individual.
Many immunotherapy experts think the greatest progress against cancer will occur when researchers figure out how to combine the approaches. – Washington Post