Bristol-Myers Drug Cocktail Stymies Melanoma Tumors

Two drugs from Bristol-Myers Squibb Co. shrank tumors in as many as half of patients with advanced melanoma, according to early research that may pave the way for cocktails that trigger the immune system to destroy cancer.

In the study, 52 patients were simultaneously treated with Bristol-Myers’s melanoma drug Yervoy and nivolumab, its experimental therapy that targets the immune system in a different way. Tumors shrank in 40 percent of patients, and in 53 percent of those who got the most effective dose combination, according to data released yesterday in advance of the American Society of Clinical Oncology meeting scheduled to begin May 31.

Bristol-Myers, Merck & Co. and Roche Holding AG are competing on new cancer therapies and drug cocktails that use the immune system to seek and kill tumor cells. The treatments have the potential to reap billions of dollars in sales while lengthening patient remissions, analysts and oncologists say.

“The responses are occurring faster and the absolute amount of shrinkage is more than we have seen with either drug alone with this frequency,” said Jedd Wolchok, an oncologist at Memorial Sloan-Kettering Cancer Center in New York, and lead author on the study. “What we are seeing that is so impressive is the number of patients that have had very deep responses, their tumor burden decreasing by 80 percent or more.”

Tumors disappeared entirely in 10 percent of patients, Wolchok said.

‘Bottom End’

While the 53 percent tumor shrinkage rate “is at the bottom end of Street expectations”, the number of patients with near complete responses is “impressive”, wrote Mark Schoenebaum, an analyst with ISI Group, in an e-mail to clients after the data came out yesterday.

Bristol-Myers shares fell 3.5 percent to $42.77 at the close in New York. The company has gained 31 percent this year.

The new drugs are designed to prevent flicking what is essentially a molecular off switch, called PD-1, for immune system T-cells, the body’s key defenders against attacks from dangerous germs and infections. Many tumors may hide from the immune system by triggering this switch.

While none of the drugs has been shown in large trials to extend life, doctors are awaiting early results to gain clues about which drugs may work best in which patients.

Merck Study

In addition to research from New York-based Bristol-Myers, data was released yesterday from a preliminary study of Whitehouse Station, New Jersey-based Merck’s lambrolizumab that also targets the PD-1 system. It shrank tumors in at least 35 percent of patients with advanced melanoma, according to an abstract posted on the American Society of Clinical Oncology website from the first 85 patients in a 294-patient study.

In a third study, Basel, Switzerland-based Roche’s experimental drug MPDL3280A reduced tumor size in 29 of 140 patients with a variety of late-stage cancers. The drug helped those with lung cancer, melanoma, kidney cancer, colorectal cancer and stomach cancer. All but three of the 29 patients who responded to the drug were still being helped by it, according to a statement from the cancer doctors’ group.

Doctors are enthusiastic about immunotherapy because “this type of approach may lead to much longer lasting benefit for patients,” than many existing therapies, Sandra Horning, global head of clinical development for cancer drugs at Roche, said in a telephone interview before the data was released.

Yervoy Benefit

Yervoy, for example, doubles to 19 percent the number of advanced melanoma patients who survive four years, according to data presented last September. The medicine was approved for U.S. sale in March 2011. And in the Bristol-Myers combination trial, 90 percent of people who responded to the drug were still doing well as of February 2013, Wolchok said on a conference call with reporters.

With the new PD-1 drugs “we are seeing profound responses” in a variety of tumors, said Roy Herbst, chief of medical oncology at the Yale Cancer Center, who has been involved in testing the Roche drug.

For Bristol-Myers, strong combination therapy data “could open the door to significant potential upside” by giving the company a competitive advantage over rivals testing compounds against PD-1, said Seamus Fernandez, an analyst at Leerink Swann & Co., in a note to clients before the data was released.

While Wall Street expects Bristol-Myers’s nivolumab may garner sales of $2.5 billion to $3.5 billion in 2020, the revenue potential for it and the company’s other cancer immune therapy drugs may increase if the Yervoy-nivolumab combination works well in a variety of tumors, Fernandez said in the note.

Side Effects

The immune therapy medicines sometimes cause autoimmune side effects. Yervoy can cause severe colon inflammation, while the experimental PD-1 drugs from Bristol-Myers and Merck can cause lung inflammation. In Bristol-Myers’s trial combining its two drugs, some patients developed elevated pancreas and liver enzyme levels, Wolchok said.

Based on the results, Bristol-Myers has begun a final-stage trial combining nivolumab and Yervoy in advanced melanoma patients. It is conducting five other final-stage studies of nivolumab in lung cancer, kidney cancer, and melanoma.

Merck is conducting a 500-patient, second-stage trial of lambrolizumab in melanoma that may be large enough to gain approval without the usual required third-stage of testing. Meanwhile, Roche plans to begin a final-stage study of its drug MPDL3280A in lung cancer.