Study: Immunotherapy shrinks melanoma that has spread to brain
A combination of two drugs that enlist the immune system to fight cancer shrank melanoma that had spread to the brain in most patients, according to a Houston-led study that provides another sign of immunotherapy’s promise.
The study provides hope the cutting-edge therapy pioneered by MD Anderson Cancer Center scientist Jim Allison could help against many brain metastases, typically a last stage of the disease. The cancers of roughly 200,000 U.S. patients spread to the brain annually.
“This opens the door to investigate other cancers where there’s brain metastasis, to start proving whether it works in them, as well,” said Dr. Hussein Tawhi, an MD Anderson medical melanoma oncologist and principal investigator of the study, which was conducted at 28 U.S. sites.
Tawhi said the study will have an immediate impact on melanoma, calling it “practice-changing.” He said it proves doctors can use immunotherapy as first-line treatment of melanoma brain metastasis rather than require the patient first undergo radiation and surgery.
Immunotherapy’s success against melanoma has been well documented, but patients whose disease spreads to the brain remain the most in need, routinely excluded from clinical trials due to the severity and presumed intractable nature of their disease.
The study enlisted two checkpoint inhibitor drugs — ipilimumab and nivolumab — which release a natural brake that otherwise reins in the immune system. Allison discovered the brake and developed ipilimumab, the first such drug, jump-starting the field of immunotherapy, until then a lost cause. The approach is now considered a fourth modality of cancer treatment, along with surgery, radiation and chemotherapy.
Former President Jimmy Carter is the best known beneficiary of checkpoint inhibitor drugs for melanoma that spread to the brain. He received a third such drug, pembrolizumab, after being diagnosed with the melanoma brain metastasis in August 2015.
The study found brain metastasis had not progressed six months after treatment in 60 percent of 94 melanoma patients treated only with the two drugs. Currently, average survival for patients with brain metastases is four to five months.