* Ipilimumab cuts death risk 32-34 pct vs GP-100 vaccine
* 10-month median survival; 4 months longer than vaccine
* 1- and 2-year survival rate nearly double vaccine (Recasts, adds comments from conference)
By Bill Berkrot and Julie Steenhuysen
NEW YORK/CHICAGO, June 5 (Reuters) - Bristol-Myers Squibb Co’s (BMY.N) experimental skin cancer drug ipilimumab added an average of four months to the lives of patients with advanced melanoma, U.S. researchers said on Saturday, representing a major advance in a disease littered with drug failures.
Melanoma is one of the deadliest cancers and can quickly spread from the skin to internal organs, such as the brain.
“Once it metastasizes, the average survival is six to nine months and we really had no effective treatments for patients who have had prior treatment for melanoma,” said Dr. Steven O‘Day, one of the study’s lead investigators.
In the 676-patient study, patients who got the drug survived for an average of 10 months, compared with just over six months if they just got a vaccine treatment called gp100, investigators found.
The four-month difference represented a 67 percent increase in survival, O‘Day told reporters at the American Society of Clinical Oncology meeting in Chicago.
For some patients, the benefit was lasting, with more than 20 percent of those who took the drug still alive after two years, and some still alive even four years after treatment.
“I think this a breakthrough for the field of metastatic melanoma that has had a lot of negative Phase 3 trials in the last decade. It’s impacting survival, which is the gold standard in cancer clinical trials,” O‘Day, director of the melanoma program at the Angeles Clinic and Research Institute in Santa Monica, California, said in a telephone interview.
Ipilimumab helps to activate the immune system to fight the cancer. Doctors give it to patients in a 90-minute infusion every three weeks for a total of four doses.
All patients in the trial had previous treatment for melanoma before getting either an experimental cancer vaccine called GP-100, ipilimumab, or a combination of the two.
Both groups that got the Bristol drug had a statistically significant improvement in overall survival compared with those who just got the vaccine, researchers said.
In the two ipilimumab arms, the drug cut the risk of death from melanoma by 32 percent to 34 percent compared with the vaccine alone.
“If you look at one-year and two-year survival, there was a near doubling of benefit with ipilimumab,” O‘Day said.
One-year survival was seen in 25 percent of the vaccine patients, compared with 44 percent on the combination and 46 percent for ipilimumab alone.
After two years, 14 percent of vaccine patients were alive versus 22 percent and 24 percent in the Bristol drug arms.
In the 20 percent to 30 percent of patients for whom the drug really works, survival “tends to be months and years, not weeks and months like chemotherapy,” O‘Day said.
He said a genetic biomarker test was needed to determine just which patients were most likely to benefit from the drug.
Since the drug enlists the help of the immune system, it does have some serious side effects.
About two-thirds of patients on ipilimumab had some form of immune-related side effects compared with one-third on vaccine, researchers said.
Most were mild and completely reversible, but about 10 to 14 percent of patients had more severe side effects, such as colitis, that required treatment with steroids or immunosuppressive drugs, O‘Day explained.
Some 2 percent to 3 percent of patients on ipilimumab died from the treatment because of colon perforation or other severe immune system side effects.
Doctors would have to closely monitor patient reaction, O‘Day said, but he added the side effects could be managed.
O‘Day believes ipilimumab may also work in other types of cancer.
Leerink Swann analyst Seamus Fernandez forecasts ipilimumab sales of $575 million in 2016 with an approval for metastatic melanoma.
But some doctors worry that patients will start asking for the drug and will not be able to get it.
“This is not an FDA-approved drug,” said Dr. Lynn Schuchter, a skin cancer specialist at the University of Pennsylvania, who was not involved in the study.
“Patients are going to have a lot of hope and want this drug and it’s not going to be on their doctors’ shelves.”
She said it may be possible for patients to get the drug through melanoma centers of excellence either in a clinical trial or through a so-called compassionate use protocol.
O‘Day is counting on a speedy approval.
“We’re hopeful that this (data) is the beginning of what will be a rapid regulatory processing to try to get this drug on the market and access to more patients with melanoma,” O‘Day said. (Reporting by Bill Berkrot and Julie Steenhuysen; Editing by Peter Cooney)