AT ASH 2014
SAN FRANCISCO (FRONTLINE MEDICAL NEWS) – Early post-transplant brentuximab vedotin dramatically slows Hodgkin’s lymphoma progression in patients at high risk for relapse or progression, the phase III AETHERA study shows.
After a median follow-up of about 28 months, the primary end point of progression-free survival (PFS) per independent review increased from a median of 24 months with placebo and best supportive care (BSC) to 43 months with brentuximab and BSC (Hazard ratio, 0.57; P = .001).
Per investigator assessment, median PFS was 16 months with placebo and had not been reached with brentuximab (HR, 0.50),Dr. Craig Moskowitz reported at the annual meeting of the American Society of Hematology .
The benefit of brentuximab maintenance was consistent across every subgroup. Historically, roughly half of patients who undergo an autologous stem cell transplant will relapse.
“Once this study is published, in patients who met eligibility criteria to be on this study – and once again I’ll remind you that’s remission duration less than one year, disease outside the lymph node system, or primary refractory disease – in my opinion, this will be the standard of care,” Dr. Moskowitz said during a press briefing.
Brentuximab, an anti-CD30 antibody conjugate, is already approved in the U.S. for the management of Hodgkin’s lymphoma (HL) after failure of autologous stem cell transplantation (ASCT) or at least two prior lines of multi-agent chemotherapy in patients ineligible for ASCT.
Brentuximab is also indicated for systemic anaplastic large cell lymphoma after failure of at least one multi-agent chemotherapy regimen.
In September it was announced that AETHERA met its primary end point, but this was the first full look at the absolute survival rates and safety data.
The 2-year PFS rate for the brentuximab and placebo groups is now 63% vs. 51% per independent review and 65% vs. 45% per investigator.
“The bottom line is there’s a 20% difference in progression-free survival at 2 years upon investigator review. This has never been seen in patients with relapsed, refractory lymphoma, let alone Hodgkin lymphoma,” Dr. Moskowitz , clinical director of hematology oncology at Memorial Sloan-Kettering Cancer Center in New York City, said.
Overall survival data are immature, but was the same in both groups at 2 years (P = .62). The likelihood of showing a survival difference was not expected because 85% of patients who relapsed on the placebo arm crossed over to brentuximab, as allowed per protocol, and it’s known that brentuximab alone in auto-transplant failures improves outcomes by at least a year, he said. Also, twice as many patients who failed placebo received a second transplant.
Dr. Moskowitz stressed that nearly every patient in the trial had at least three risk factors that would place them at high risk of treatment failure and that studies have shown that for patients with this many risk factors, the chance of being cured by an auto-transplant is about 25%. The risk factors are: relapsed less than 12 months or refractory to frontline therapy, best response of partial remission or stable disease to most recent salvage therapy, extranodal disease at pre-ASCT relapse, B symptoms at pre-ASCT relapse, or two or more prior salvage therapies.
Press briefing moderator Dr. Brad Kahl of the University of Wisconsin-Madison, said Aethera is the first study to show a significant benefit for a post-transplant strategy.
“The biggest question in my mind is whether the application of maintenance brentuximab vedotin is just delaying the inevitable relapse, so the patients will still relapse, just later, or has the brentuximab taken patients who are destined to relapse and turned them into a cured patient,” Dr. Kahl said. “We don’t know the answer to that question. That will become apparent with more time.”
Dr. Moscowitz observed that relapses almost never happen after two year, adding, “So if you’re in remission at two years after stem cell transplantation for Hodgkin lymphoma, you are likely to be cured.”
AETHERA enrolled 329 patients with Hodgkin’s lymphoma and randomly assigned them after ASCT to brentuximab vedotin 1.8 mg/kg or placebo given every 3 weeks for up to 16 cycles, plus BSC. All patients were required to have achieved a complete response, partial remission, or stable disease to salvage therapy prior to ASCT. Their median age was 32 years and 53% were male.
Roughly 60% were refractory to upfront therapy, 43% in the brentuximab arm and 48% of controls had received 2 or more prior systemic therapies, and a third in each arm had extranodal involvement.
Consolidation therapy with brentuximab was generally well tolerated, Dr. Moskowitz said. Peripheral sensory neuropathy was the most common side effect, experienced at any grade in 67% on brentuximab vs. 19% of controls and at grade 3 in 13% vs. 1%. There were no grade 4 events and 85% of patients had resolution or improvement with dose reductions or stopping the drug.
Other adverse events in the brentuximab and control groups were neutropenia (35% vs. 12%), upper respiratory tract infections (26% vs. 23%), and fatigue (24% vs. 18%). Two patients died within 40 days of dosing with brentuximab, one from treatment-related acute respiratory distress syndrome associated with pneumonitis and one following an episode of treatment-related acute pancreatitis that had resolved at the time of death, he reported.
Based on the results, study sponsor Seattle Genetics is expected to seek approval for brentuximab in this consolidation setting in the first half of 2015, according to a statement from the company. The ongoing phase III ECHELON-1 and ECHELON 2 trials in HL and mature T-cell lymphomas are looking at the use of brentuximab in frontline disease.