Lutathera consists of a radioactive isotope, Lu 177, that is linked to a molecule called dotatate. The molecule attaches itself to certain types of neuroendocrine cancer cells that have a receptor called somatostatin on their surface, delivering the radiation released by Lu 177, which helps kill the cells. The therapy is expected to benefit many patients because most of these patients have tumors that express somatostatin receptors.
New Drug Gives Clear Advantage for Patients
Patients are typically treated with injections of a somatostatin analog. The drugs are synthetic versions of a hormone produced in the brain and digestive tract that affects the function of the gastrointestinal tract. These drugs can help control symptoms and control gastroenteropancreatic neuroendocrine tumor growth. Some patients with disease that doesn’t respond to, or stops responding to, somatostatin analogs, are also prescribed the medication Afinitor (everolimus). But Afinitor is associated with side effects, and it’s not clear how well it actually improves patient survival. Lutathera was approved based on a randomized, clinical trial of 229 patients led by Jonathan Strosberg, MD, an associate member of the gastrointestinal oncology department at Moffitt Cancer Center in Tampa, Florida. The trial, which appeared in the January 12, 2017, issue of the New England Journal of Medicine, compared Lutathera with the conventional therapy — a somatostatin analog. All of the patients had inoperable, somatostatin-receptor-positive NETs that had not responded adequately to standard treatment. The patients received either Lutathera plus the standard dose of a somatostatin analogue or a higher dose of the somatostatin analogue alone. The patients who received Lutathera and the somatostatin analogue lived longer without their cancer progressing compared with the patients who received the higher dose of somatostatin analogue alone. Overall, patients in the Lutathera arm of the study lived 80 percent longer without the cancer progressing, Dr. Strosberg says. Another study, performed in the Netherlands, found that 16 percent of patients with neuroendocrine tumors of the pancreas or gastrointestinal tract receiving Lutathera had partial or complete shrinkage of their tumors. This new medication has been used extensively in Europe but is just now available in the United States.
GEP-NETS: Difficult to Treat Tumors
Gastroenteropancreatic neuroendocrine tumors are challenging to treat, says Strosberg. About one-third to one-half of patients are diagnosed when the cancer is already at an advanced stage. “These tumors are sometimes slow growing, but in general these are a very diverse group of tumors, and the treatment options have been limited,” he says. “We use imaging to see if a patient is somatostatin receptor positive,” says Strosberg. “These drugs target that receptor so they require imaging that visualizes the somatostatin receptor. In recent years, we’ve seen the development of more sensitive and accurate scans. Most patients with GEP-NETs have this type of cancer.” Lutathera, however, presents the most clear-cut advantage for patients who have not done well with first-line therapies. The drug is delivered intravenously in four treatments spaced over eight months. Lutathera has been associated with some side effects, including nausea and decreases in white blood cell count. But these problems are treatable, Strosberg says.
Patients Should Seek Out Care in Academic Centers
The success of Lutathera is part of a series of advances in recent years in the treatment of all types of neuroendocrine tumors, Strosberg notes. A group of experts in the field last year published the North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Medical Management of Midgut Neuroendocrine Tumors to ensure patients are treated appropriately. The guidelines were published in the July 2017 issue of the journal Pancreas. Patients seeking treatment for neuroendocrine tumors should be aware that a lot has changed in recent years. “Lutathera won’t be widely available in community practices,” Strosberg says. “But it will be available in academic centers, and that’s where the majority of patients with neuroendocrine tumors are treated. Patients with these tumors should seek care from a neuroendocrine tumor specialist.”
