AT ASH 2016
SAN DIEGO (FRONTLINE MEDICAL NEWS) – For patients with CD30 expressing cutaneous T-cell lymphoma, antibody-drug conjugate therapy with brentuximab vedotin significantly outperformed two standard regimens in the phase III ALCANZA trial.
After a median of 17.5 months of follow-up, 56% of patients receiving brentuximab vedotin had an objective response lasting at least 4 months, versus 13% of patients treated with physician’s choice of methotrexate or bexarotene (P less than .0001), Youn H. Kim, MD , said during an oral presentation at the annual meeting of the American Society of Hematology.
As in past studies, brentuximab vedotin caused high rates of peripheral neuropathy, but more than 80% of cases improved or resolved over time, she said.
This is the first reported phase III trial to convincingly show that a new systemic agent outperformed standard therapies for cutaneous T-cell lymphoma (CTCL), which tend to have inadequate and short-lived efficacy, stated Dr. Kim, of Stanford (Calif.) University. Brentuximab vedotin not only met the primary endpoint, but all other predefined endpoints, including progression-free survival and a quality-of-life measure, she said.
“These compelling results have potential practice-changing implications,” she concluded.
Brentuximab vedotin (Adcetris) targets CD30, which is expressed in skin lesions of about half of patients with CTCL. A protease-cleavable linker attaches an anti-CD30 monoclonal antibody to monomethyl auristatin E, which disrupts microtubules when released into CD30-positive tumor cells ( Blood. 2013;122:367 ). The agent showed clinical activity against CTCL in two previous phase II trials of CTCL.
Accordingly, the international, open-label phase III ALCANZA study enrolled 128 treatment-experienced patients with CD30-expressing mycosis fungoides or primary cutaneous anaplastic large cell lymphoma. Patients were randomly assigned to receive brentuximab vedotin (1.8 mg/kg once every 3 weeks) or physician’s choice of either methotrexate (5 to 50 mg once weekly) or bexarotene (300 mg/m2 once daily) for up to 16 3-week cycles, or until disease progression or unacceptable toxicity. Methotrexate or bexarotene were designated “physician’s choice” because they are used worldwide for treating CTCL, according to Dr. Kim.
To capture both the rate and duration of response, researchers defined objective response lasting at least 4 months as the primary endpoint. Brentuximab vedotin more than quadrupled the likelihood of this outcome when compared with the standard CTCL regimens, a trend that spanned key demographic and clinical subgroups, Dr. Kim said.
“All endpoints were highly [statistically] significant,” she further reported. For example, the objective response rate with brentuximab vedotin was 67%, versus 20% for methotrexate or bexarotene. Respective rates of complete response were 16% and 2%, and median durations of progression-free survival were 17 and 4 months, translating to a 73% lower risk of progression or death with brentuximab vedotin (95% confidence interval, 57%-83%). Patients who received brentuximab vedotin also reported about a three-fold greater improvement on the Skindex-29 symptom domain, compared with the physician’s choice group (–29 vs. –9 points; P less than .0001).
The safety profile of brentuximab vedotin resembled that seen in previous studies, Dr. Kim said. Most notably, 67% of patients developed peripheral neuropathy, and 9% developed grade 3 peripheral neuropathy. This usually improved or resolved over about the next 22 months. Diarrhea, fatigue, and vomiting affected about a third of patients on brentuximab vedotin, and about one in four stopped treatment because of adverse events, compared with 8% of the physician’s choice arm. Rates of serious adverse events were 41% and 47%, respectively. One brentuximab vedotin recipient died of multiple organ dysfunction syndrome that investigators attributed to treatment-associated necrosis of peripheral tumors. They identified no other treatment-related deaths.
Seattle Genetics and Takeda funded the trial. Dr. Kim disclosed ties to Takeda and Seattle Genetics, as well as several other pharmaceutical companies.