The longest response rate lasted six months.
A new immunotherapy can slow the progress of metastatic melanoma, according to a small study presented at the 2017 World Congress of Melanoma.
The treatment uses tumor infiltrating lymphocytes (TILs) extracted from patients’ tumors, The cells are then genetically altered and rapidly grown in the lab, before being injused back into the patient. In addition to displaying some ability to control malignancy, the study found very little added toxicity.
The research showed a response rate of 86 percent in seven patients with metastatic melanoma who had received other cancer treatments. The duration of the response was limited, with two patients responding for six months.
"This is one of the first studies to use gene-modified TILs in metastatic melanoma patients. Before this, there had been just a couple other studies treating just a handful of patients," said investigator Rodabe N. Amaria, M.D., Department of Melanoma Medical Oncology, Division of Cancer Medicine.
The TIL manufacturing process was broken into two steps, starting with four to six weeks of patient and laboratory procedures. In the lab, tumors were fragmented and cultured with Interleukin-2 (IL-2), until there were at least 40 million T cells available.
After this, the cells were cryopreserved or used fresh. Prior to infusion of the TILs, patients were checked to see whether they could undergo treatment with high-dose IL-2, which was followed by hospital admission eight days before infusion.
During these checks and hospitalization, the T cells underwent a rapid expansion protocol to grow the millions of cells into potentially billions, Amaria said.
Before infusion, patients underwent seven days of lymphodepleting chemotherapy, consisting of cyclophosphamide and fludarabine. After infusion, high-dose IL-2 was administered to promote T cell persistence and activation.
The pilot study enrolled seven patients with melanoma. Patient age ranged from 29 to 68. The average number of prior therapies was four. All but one had normal LDH levels.
Overall, one patient experienced a partial response, and five had stable disease at the time of the assessment. One patient developed progressive disease following treatment.
The duration of response was not consistent across all patients who showed signs of stable disease. Overall, two patients showed signs of a persistent response, lasting longer than six months. For one of these patients, a consistent drop in tumor burden, which was close to 90 percent, was seen out to 17 months.
"Three patients had an initial response and then progression at the three-month time point," Amaria said.
Overall, there was no increase in toxicity observed following the infusion of the TILs, Amaria said.
Adverse events reported included anemia and thrombocytopenia. Both of which required transfusions. There was also a low level of febrile neutropenia.
After infusion with the TILs, there were also expected toxicities related to treatment with high-dose IL-2.
"We haven't had any major issues with this," said Amaria. "We are able to treat patients on our own melanoma unit, patients don't need to get transferred to the ICU. Overall, this is a very safe protocol."
In other trials, TILs without genetic modification have shown moderate benefits for treating patients with melanoma. The phase 1 study continues to enroll participants at the MD Anderson Cancer Center. The trial has an enrollment goal of 15 patients.