IPILIMUMAB EFFECTIVE AFTER STEM CELL TRANSPLANTATION

The immunotherapy ipilimumab (Yervoy, Bristol-Myers Squibb Company) showed impressive activity in patients with hematologic malignancies who experienced relapse after receiving a hematopoietic stem cell transplant (HSCT). These patients have limited treatment options and a poor prognosis.

The new results come from a phase 1/1b study published onlineJuly 14 in the New England Journal of Medicine.

HSCT offers the best chance of a cure for some patients with hematologic malignancies. Unfortunately, more than one third of patients who undergo HSCT experience disease relapse, the authors explain. "The prognosis for these patients is poor; the majority die within 1 year after relapse despite salvage chemotherapy, donor-lymphocyte infusion, or retransplantation," they write.

In the new study, they report that ipilimumab elicited responses in 32% of patients. With a median follow-up of 15 months, the 1-year overall survival was 49%; the median duration of response has not been reached.

"This is the first time that targeting an immune checkpoint therapeutically has led to striking responses in patients with a broad range of hematologic malignancies who have relapsed following allogeneic transplantation," lead author Matthew S. Davids, MD, from the Dana-Farber Cancer Institute, Boston, told Medscape Medical News.

"In patients who relapse following transplantation, the use of ipilimumab may reawaken a dormant immune system and restore antitumor effects," he said.

Medscape Medical News contacted several experts who were not associated with this study and who employ HSCT in the treatment of patients with hematologic malignancies for their reaction to this report.

"This is an exciting and important study and impacts patients who are in a challenging situation," Gita Thanarajasingam, MD, hematologist at the Mayo Clinic, Rochester, Minnesota, told Medscape Medical News.

Dr Thanarajasingam explained that patients who experience relapse after allogeneic transplant tend to do poorly.

"We have been reticent to use immunotherapy in patients who relapse following allogeneic transplantation," she said, citing concerns about toxicity. She noted that although immune-related adverse events and graft-vs-host disease (GVHD) occurred in some patients in the study, the clinical responses are impressive.

"Just as with the undertaking of an allogeneic transplant in the first place, immune checkpoint blockade after allogeneic transplant should be regarded as a treatment with the potential for high risk and high reward," Dr Thanarajasingam said.