New York, NY —Growing evidence suggests that the potent pan-deacetylase inhibitor panobinostat (LBH589) shows promising clinical activity in heavily pretreated patients with relapsed/refractory Hodgkin’s lymphoma.
Panobinostat targets both epigenetic and non-epigenetic oncogenic pathways and is among a group of novel antineoplastic agents that inhibit the activity of histone deacetylases, said Myron Czuczman, MD, of Roswell Park Cancer Institute in Buffalo, New York, at the Chemotherapy Foundation Symposium held November 10-13, 2009.
Panobinostat is currently under clinical investigation in a variety of solid tumors and hematologic malignancies. Promising results in relapsed/refractory Hodgkin’s lymphoma were presented earlier in the year at the European Hematology Association annual meeting in Berlin, Germany.
Dr Czuczman updated those results from the phase 1/2 trial of Hodgkin’s lymphoma patients with a variety of advanced hematologic malignancies who were refractory to treatments. One group of patients had leukemias or high-risk myelodysplastic syndromes and another group had lymphoma or myeloma.
The patients received 2 schedules of oral panobinostat: once-a-day on Monday, Wednesday, and Friday (MWF) every week or MWF every other week. PET and CT data were evaluated for best response.
So far, 61 patients in the lymphoma and myeloma group have been treated, and 53 patients have been evaluated. The investigators have recorded 1 complete response, 10 partial responses, and 31 patients with stable disease. Of the 31 patients with stable disease, 25 patients had a decrease in tumor burden, and additional responses are likely in this group, said Dr Czuczman.
For patients in the lymphoma or myeloma group, “about three-quarters of the patients had some evidence of antitumor activity,” said Dr Czuczman.
He noted that this group has had a range of prior therapies, including surgery, radiotherapy, stem cell transplantation, and cytotoxic chemotherapy. The median number of prior chemotherapeutic regimens was 5. “These patients had limited treatment options,” he said.
Safety analysis reveals that the most common grade 3/4 adverse events with panobinostat therapy have been thrombocytopenia, neutropenia, fatigue, and anemia. The maximum tolerated dose for patients in this group is 40 mg MWF every week or 60 mg MWF every other week. “More than 60% of the patients have had dose reductions, mostly due to cytopenia, which is not surprising given their limited bone marrow reserve,” he said.
Dr Czuczman said that panobinostat was well tolerated and induced antitumor activity in heavily pretreated patients. “The drug has a role in the treatment of patients with treatment-refractory Hodgkin’s lymphoma and possibly in earlier stages of the disease as well,” he said.
Further updates of this ongoing study will follow, and a global phase 2 study is currently underway using panobinostat at 40 mg/day on MWF every week in patients with Hodgkin’s lymphoma.
In addition, Dr Czuczman has started a phase 1 study in relapsed/refractory Hodgkin’s lymphoma or non-Hodgkin’s lymphoma patients using panobinostat in an intrapatient dose modification program that allows patients to escalate or deescalate doses depending on their tolerance of the drug.
