Oct 8 Merck & Co's immunotherapy
Keytruda proved effective as an initial treatment for nearly a
quarter of patients with advanced bladder cancer too frail for
standard cisplatin chemotherapy, according to interim results
from a study presented on Saturday.
Evaluation of the first 100 patients from a 374-patient
trial showed that 24 percent experienced significant tumor
shrinkage, including 6 percent with complete responses, meaning
no detectable cancer, researchers said.
Keytruda belongs to a class of drugs that block a mechanism
tumors use to evade detection, allowing the immune system to
recognize and attack cancer. It is approved to treat advanced
melanoma, non-small cell lung cancer and head and neck cancers.
In May, Roche's Tecentriq became the first of the
new immuno-oncology drugs to gain U.S. approval to treat bladder
cancer that has progressed following chemotherapy treatment.
Tecentriq had remarkably similar results to Keytruda in its
earlier trial of advanced bladder cancer patients ineligible for
cisplatin chemotherapy - a 24 percent response rate, including 7
percent complete responses.
The new data on top of the Roche data confirm that these
drugs have anti-tumor activity and are safe in this patient
population, Dr. Arjun Balar, the study's lead investigator from
New York University Langone Medical Center, said in a telephone
"It further strengthens the argument that these drugs should
be considered a potential new standard of care," added Balar,
who presented the results at the European Society of Medical
Oncology meeting in Copenhagen.
The median duration of Keytruda responses had not been
reached, but 83 percent have so far lasted at least six months,
"So we know responses are durable in these patients," Balar
Typical survival with advanced bladder cancer in
cisplatin-ineligible patients is nine to 10 months.
Cisplatin extends survival by a few months, but nearly half
of bladder cancer patients cannot endure its toxicity. Most
patients in the Keytruda trial had a grim prognosis with cancer
that had spread to the lungs, liver or bones.
Biomarker testing of tumors and immune cells for the PD-L1
protein the drug targets found a greater response rate among
patients whose PD-L1 expression was 10 percent or more,
including four of the six complete responses.
While 5 percent of patients dropped out due to Keytruda side
effects, researchers said the level of toxicity and
discontinuation rate was far lower than what is typical with
(Reporting by Bill Berkrot; Editing by Cynthia Osterman)