For Hodgkin lymphoma patients who progress after a stem cell transplant, two new treatments may bring new hope.
While most patients with Hodgkin lymphoma are cured with standard chemotherapy, a percentage of patients progress and need further chemotherapy and a stem cell transplant. However, patients who relapse after transplant have few treatment options left. Two studies presented at the 2010 American Society of Hematology annual meeting were found to be beneficial in this patient population.
In a phase 2 trial, researchers found that an investigational agent called brentuximab vedotin (SGN-35), which targets the CD30 antigen on the surface of Hodgkin lymphoma cells, is effective in patients who have relapsed after an autologous stem cell transplant (where stem cells taken before treatment are re-infused into the patient after high-dose chemotherapy). A third of patients had a complete remission while on the drug, and after one year, the median duration of response has not yet been reached—meaning more than half of patients in complete remission have yet to relapse. In addition, tumor shrinkage occurred in 94 percent of patients with the response lasting a median of 29 weeks.
About 47 percent of patients in the trial developed peripheral neuropathy. In most patients, the side effect went away once the drug was discontinued or treatment completed, or shortly thereafter. Other common side effects included fatigue, nausea, upper respiratory tract infection and diarrhea.
Robert Chen, MD, who led the study at City of Hope in Duarte, California, stated that the drug is currently being combined with standard chemotherapy, aiming at improving treatment outcome.
Studies are currently ongoing to test this strategy. In addition, the manufacturer of the drug announced it is planning an early access program (possibly in early 2011) that will allow qualified patients access to the drug while it awaits review by the Food and Drug Administration. The company, Seattle Genetics, also plans to submit the drug for approval for anaplastic large cell lymphoma, a rare but aggressive type of non-Hodgkin lymphoma.
Another phase 2 trial in relapsed or refractory Hodgkin lymphoma looked at using panobinostat in patients who had relapsed after a stem cell transplant. More than three-quarters of the 129 patients on panobinostat saw their tumors shrink, with five complete responses and 30 partial responses.
The most common side effect associated with panobinostat is thrombocytopenia (low platelet count). Based on the pivotal trial’s results, the drug’s maker, Novartis, is planning to submit panobinostat for approval in this patient population. A phase 3 trial, called PATH, in post-transplant patients is now enrolling to examine the drug’s efficacy further. Panobinostat is also being combined with conventional chemotherapy in ongoing clinical trials.
Panobinostat is a histone-deacetylase inhibitor, which acts against several cancer-growth pathways. In addition to relapsed and refractory Hodgkin lymphoma, panobinostat is also being looked at a number of other blood cancers, including multiple myeloma, and solid tumors.
While the two trials looked at patients with relapsed Hodgkin lymphoma, the patient populations were not identical, and therefore, one cannot compare the results of these two studies.