A new generation of drugs
designed to trigger the immune system to fight cancer is offering the prospect
of a "clinical cure" for some melanoma skin cancer patients who until
a few years ago were more likely to be facing a swift death.
Cancer specialists
gathering for a European conference said the so-called
immunotherapy drugs, a class led by Bristol-Myers Squibb's Yervoy, or
ipilimumab, have transformed an area of oncology in which until recently
doctors barely had time to get to know their patients.
Stephen Hodi, assistant
professor of medicine at the Dana-Farber Cancer Institute in the United States,
said he was cautious about using the term cure, but described recent advances
as a "paradigm shift".
He said the
success of this new generation of medicines meant some melanoma patients would
now be living with a chronic disease, rather than facing imminent death.
Moving extremely fast
"This is a really
amazing time... A few years ago we could never have imagined using the C-word,
cure, in melanoma, but we are headed that way," he said.
"Ipilimumab opened a
door, and now the field is moving extremely fast," he told the European Cancer Congress in Amsterdam.
Yervoy, approved by
regulators in 2011, was hailed as a breakthrough treatment in melanoma after it
became the first drug ever to extend survival in patients with advanced forms
of the melanoma.
A new type of drug
A type of drug known as a
human monoclonal antibody, it activates the body's immune system to fight the
cancer by targeting a protein receptor called Cytotoxic T-Lymphocyte Antigen 4,
or CTLA-4.
On average, Yervoy added
only about four months of life in pivotal trials, but around 20% of patients
had an impressively durable response to the drug.
Hodi presented new data from the largest and longest study of overall survival for patients
treated with Yervoy which showed some of them can survive for up to 10 years.
Clinical cure
Alexander Eggermont of the
Institut Gustave Roussy comprehensive cancer centre in France, who specialises
in the treatment of melanoma, said Hodi's results suggested some patients could
be effectively cured of their cancer – a concept known as a "clinical
cure" – with the drug helping the immune to keep the disease in check.
"Patients apparently
can keep residual tumours under control for a long time when the immune system
is properly 'reset', and the concept of 'clinical cures' becomes a
reality," he said.
And with a next generation
of immunotherapy drugs - designed to disable proteins called PD1 and PDL1 that
prevent the immune system from spotting and attacking cancer cells – already
being tested alone and in combination with Yervoy, there is "tremendous
promise" in the treatment of melanoma, said Hodi.
Next generation drug
Bristol-Myers Squibb is
conducting late stage trials of its next-generation drug, nivolumab, in
advanced melanoma, while rival US drug maker Merck is developing a
competitor, lambrolizumab, which in early-stage trials helped shrink tumours in
38% of advanced melanoma patients.
Swiss drug maker Roche's
also has a leading contender – MPDL3280A – in this class.
"These (Yervoy)
survival results could even double or triple with anti-PD1/PDL1 monoclonal
antibodies, and metastatic melanoma could become a curable disease for perhaps
more than 50% of patients over the coming five to 10 years,"
Eggermont said.