* 44 pct improvement in progression-free survival in study
* Novartis' ribociclib to take on Pfizer blockbuster Ibrance
By Ben Hirschler
COPENHAGEN, Oct 8 An experimental Novartis
pill given with an older drug kept advanced breast
cancer in check far longer than standard treatment alone,
putting it on track to challenge Pfizer's blockbuster
Ibrance, data showed on Saturday.
Patients taking ribociclib with letrozole were 44 percent
less likely to see their disease progress or die, a keenly
awaited clinical trial found.
Novartis' ribociclib works in a similar way to Ibrance and
is set to be second to market in the category, since it could go
on sale next year, ahead of rivals like Eli Lilly's
Ibrance itself has been quickly adopted by oncologists and
is tipped by analysts to sell some $2.1 billion in 2016,
according to Thomson Reuters consensus forecasts.
The 44 percent reduction in progression-free survival seen
with ribociclib, which is also known as LEE011, compared with a
42 percent fall reported in a comparable late-stage trial
"We need to be cautious about cross-trial comparisons but we
can say LEE011 is at least as good," Alessandro Riva, head of
cancer drug development at Novartis, told Reuters.
Like Ibrance, ribociclib caused higher levels of
neutropenia, a decline in white blood cells. The Novartis drug
was also associated with signals of potential liver and heart
problems, although these issues were well managed.
"The addition of ribociclib to letrozole does increase the
rate of toxicity, but overall, if we evaluate the magnitude of
clinical benefit, there is definitely a benefit to be gained
from adding ribociclib," said Giuseppe Curigliano of the
European Institute of Oncology.
Novartis announced in May that the 668-patient trial was a
success but full details were only unveiled in Copenhagen at the
annual European Society for Medical Oncology congress.
Patients on letrozole alone went a median 14.7 months before
their disease progressed, while the median point was not reached
in the ribociclib combination arm at the data cut-off point
because so many of those patients remained healthy.
The number of deaths in the study was also too low to allow
researchers to calculate an impact on overall survival.
In August, Novartis won breakthrough therapy designation
from U.S. regulators for ribociclib as a first-line treatment
for advanced breast cancer and the company plans to file the
medicine for approval worldwide this year.
Like Pfizer's Ibrance, which has a U.S. list price of around
$10,000 a month, ribociclib blocks enzymes known as
cyclin-dependent kinases 4 and 6.
Both drugs are designed for patients whose tumours grow in
response to oestrogen and whose cancer is not caused by the HER2
protein. This is the most common type of breast cancer.
(Editing by Susan Thomas)