(In 2nd paragraph adds dropped word "not" to show that vaccine
also shrank tumors not injected with the drug.)
By Bill Berkrot
March 14 An experimental Amgen Inc
cancer vaccine used to treat advanced melanoma, the deadliest
form of skin cancer, proved effective in a late-stage study in
shrinking tumors in a way that suggests the drug triggered the
intended systemic immune response, according to data presented
The vaccine shrank tumors that were directly injected with
the drug and tumors around the body that were not injected,
according to the data.
The drug, talimogene laherparepvec, also known as T-vec, is
an engineered virus designed to replicate inside the injected
tumor, killing cancer cells there, as well as prime the immune
system to attack other cancer cells around body.
Dr. Robert Andtbacka, one of the study's lead investigators,
in a telephone interview, called the results "very encouraging."
Amgen last year released initial data from the 295-patient
Phase III study showing that T-vec succeeded in demonstrating a
significant tumor response that lasted at least six months. The
latest data analyzed 4,000 tumor lesions to study the response
to the drug in injected versus non-injected tumors.
Of the directly injected tumors, 64 percent shrank by at
least half, and 47 percent of those had a complete response,
meaning the lesion had disappeared, researchers said.
Of the uninjected lesions in the skin or lymph nodes, known
as non-visceral tumor lesions, 34 percent shrank by at least
half with a complete response seen in 21 percent of those.
"We also want to see responses in distant lesions that are
not injected such as in the liver, in the lung and other
places," Andtbacka explained.
Of those so-called visceral tumors on solid organs, 15
percent shrank by at least 50 percent, said Andtbacka, who
presented the data at the Society of Surgical Oncology Cancer
Symposium in Phoenix.
"This indicates to us that we have activation of the immune
system to fight these tumors at a distant site," Andtbacka said.
"This is a new generation of oncolytic immunotherapy where
you're seeing very robust responses in injected lesions but
also robust responses in non-injected lesions. This bodes well
for the future for this product," added Andtbacka, an associate
professor in the division of surgical oncology at the University
of Utah School of Medicine.
Amgen said it expects to have further data in the first half
of this year showing whether T-vec ultimately helped patients in
the study to live longer. The company has not yet said when it
will apply for approval of the medicine.
Andtbacka said he expects the future of the drug will
involve its use in combination with other types of cancer
immunotherapies, especially in treating patients with non
injectable visceral tumors.
Amgen is already testing T-vec in combination with
Bristol-Myers Squibb's melanoma drug Yervoy and has
agreed to study T-vec in combination with Merck & Co's
experimental immunotherapy from a highly promising class called
Melanoma is the most aggressive form of skin cancer. About
132,000 melanoma cases occur globally each year, according to
World Health Organization.
"We are extremely excited about the data and the potential
for combinations with other treatments," said David Chang,
Amgen's head of global oncology development.
(Reporting by Bill Berkrot; Editing by Leslie Adler)