Promising results on the treatment of Classical Hodgkin lymphoma (cHL) were presented during the 56th Annual Meeting of the American Society of Hematology (ASH) by Dr. Craig H. Moskowitz, Clinical Director of the Division of Hematologic Oncology at Memorial Sloan Kettering Cancer Center (MSK).
In the study titled “PD-1 Blockade with the Monoclonal Antibody Pembrolizumab (MK-3475) in Patients with Classical Hodgkin Lymphoma after Brentuximab Vedotin Failure: Preliminary Results from a Phase 1b Study”, the research team showed that 66% of the patients with cHL treated with the immunotherapy drug pembrolizumab had total or partial response against the malignancy.
“These results are quite extraordinary given the dire circumstances these patients were facing,” said Dr. Moskowitz, in a press release. “Pembrolizumab has already been approved for patients with advanced melanoma and we’re excited that the drug is producing responses in other cancer types.” he added.
Pembrolizumab is an inhibitor of the programmed cell death protein 1 (PD-1), a T cell surface receptor that generally regulates the immune cell responses by inhibiting T cell activation. There are a number of cancers that have developed strategies to inhibit this regulatory mechanism of T cell activation by binding to PD-1, allowing cancer cells to evade immune responses by T cells. Thus, by inhibiting PD-1 function, this drug enables an efficient T cell immune response against tumors.
The study enrolled 29 patients with cHL that did not respond to brentuximab vedotin therapy and 20 patients that after autologous stem cell transplantation had a tumor relapse. The research team observed that 21% (n=6) of the patients had a complete response and 45% (n=13) had partial remission after 12 weeks of treatment. The patients did not show any severe side effects besides one patient that stopped the treatment due to a moderate side event.
“Phase I studies are designed for patients who have few, if any, treatment options left,” said Dr. Moskowitz. “Using the immune system as a weapon against cancer is just now beginning to gain momentum. The results of this study are encouraging as we gather evidence that immunotherapies have the potential to work in many different types of cancer.” he added.
Another study on a second potential treatment for Hodgkin lymphoma entitled “Nivolumab in Patients with Relapsed or Refractory Hodgkin Lymphoma – Preliminary Safety, Efficacy and Biomarker Results of a Phase I Study” was also presented during the ASH Annual Meeting and published in the New England Journal of Medicine.
In this study, the research team evaluated the safety and efficacy of nivolumab treatment, another PD-1 inhibitor, in cHL patients that did not respond to a previous therapy or had a tumor relaps after autologous stem cell transplantation. The researchers observed that 4 patients (17%) had a full response and 16 patients (70%) had partial remission, after 24 weeks. Furthermore, only 3 cases were registered concerning severe side effects.
“These data are the first to be reported for a completed study of a PD-1 inhibitor in Classical Hodgkin lymphoma,” said Alexander M. Lesokhin, MD, a medical oncologist at MSK and co-senior author of the study. “This is good news for Hodgkin lymphoma patients and for the advancement of immunotherapies. It’s an exciting time to be an oncologist.”
These promising results led the U.S. Food and Drug Administration to grant a Breakthrough Therapy Designation to nivolumab for relapsed cHL. Also, MSK and other institutions are preparing a large phase II trial for nivolumab treatment.