Photo by Larry Young
SAN FRANCISCO—Two phase 2 studies testing mogamulizumab in peripheral T-cell lymphomas (PTCLs) suggest that higher response rates don’t necessarily translate to an improvement in progression-free survival (PFS).
The anti-CCR4 antibody produced a higher overall response rate (ORR) in a Japanese study than in a European study—34% and 11%, respectively.
However, median PFS times were similar—about 2 months in both studies.
This similarity is all the more interesting because the studies enrolled different types of patients and followed different dosing schedules, according to Pier Luigi Zinzani, MD, PhD, of the University of Bologna in Italy.
Dr Zinzani discussed details of the European experience testing mogamulizumab in PTCL, comparing it to the Japanese experience, in a presentation at the 7th Annual T-cell Lymphoma Forum.
Kensei Tobinai, MD, PhD, of the National Cancer Center Hospital in Tokyo, Japan, also reviewed the Japanese experience (TCLF 2013, JCO 2014) during the meeting’s keynote address and presented data from an ancillary analysis of this study (which is unpublished).
All of the research was sponsored by Kyowa Hakko Kirin Co., Ltd., the company developing mogamulizumab.
The Japanese experience
The Japanese study included 29 patients with PTCL and 8 with cutaneous T-cell lymphoma (CTCL). All patients had relapsed after their last chemotherapy regimen, and none had received an allogeneic stem cell transplant (allo-SCT). The PTCL patients had a median age of 67, and 69% were male.
All patients received mogamulizumab at 1.0 mg/kg/day weekly for 8 weeks. The ORR was 35%—34% for PTCL patients and 38% for CTCL patients.
Among PTCL patients, there were 5 complete responses (CRs) and 5 partial responses (PRs). Nine patients had stable disease (SD), and 10 progressed.
Of the 16 patients with PTCL-not otherwise specified (PTCL-NOS), 1 had a CR, 2 had a PR, 6 had SD, and 7 progressed. Of the 12 patients with angioimmunoblastic T-cell lymphoma (AITL), 3 had a CR, 3 had a PR, 3 had SD, and 3 progressed. The only patient with ALK- anaplastic large-cell lymphoma (ALCL) had an unconfirmed CR.
The ancillary analysis showed that tumor shrinkage of the target lesions occurred in 72% (21/29) of patients with PTCL. The patients’ median duration of response was 6.4 months, and the median time to response was 1.9 months.
Overall, the median PFS was 3.0 months—2.0 months in patients with PTCL and 3.4 months in patients with CTCL.
Common adverse events (for both PTCL and CTCL patients) included lymphopenia (81%), skin disorders (51%), leukopenia (43%), neutropenia (38%), thrombocytopenia (38%), pyrexia (30%), acute infusion reactions (24%), and anemia (14%).
Dr Tobinai noted that these results are not as favorable as those observed when patients with adult T-cell leukemia-lymphoma receive mogamulizumab.
“But compared to the efficacy rate of other approved agents—pralatrexate and romidepsin—this antibody has promising efficacy,” he said.
In fact, the results of this study prompted the December approval of mogamulizumab to treat PTCL and CTCL patients in Japan.
The European experience
The European study differed from the Japanese study in a few ways, Dr Zinzani pointed out. The European study only enrolled patients with PTCL. And it included patients with relapsed (49%) or refractory (51%) disease, whereas the Japanese study only included relapsed patients.
Furthermore, the Japanese study did not include any patients with an ECOG performance status of 2, while the European study did (39%). And the dosing schedule differed between the 2 studies.
In the European study, patients received mogamulizumab at 1 mg/kg once weekly for 4 weeks and then once every 2 weeks until they progressed or developed unacceptable toxicity.
There were 38 patients in the safety analysis. They had a median age of 58.5 years, and 61% were male.
Thirty-five of these patients were included in the efficacy analysis. They had a median of 2 prior treatments (range, 1-8), and 17 patients (49%) had responded to their last therapy.
The patients had PTCL-NOS (43%, 15/35), AITL (34%, 12), transformed mycosis fungoides (9%, 3), ALK- ALCL (11%, 4), and ALK+ ALCL (3%, 1).
The ORR was 11% (n=4), and 46% of patients (n=16) had SD or better. Two patients with PTCL-NOS responded, as did 2 with AITL.
Six patients with PTCL-NOS had SD, as did 3 with AITL, 1 with transformed mycosis fungoides, and 2 with ALK- ALCL.
The median duration of response (including SD) was 2.9 months. And the median PFS was 2.1 months. Two patients (1 with ALK- ALCL and 1 with PTCL-NOS) went on to allo-SCT.
The most frequent adverse events (occurring in at least 10% of patients) were drug eruption (n=12), pyrexia (n=9), pruritus (n=7), diarrhea (n=7), cough (n=6), vomiting (n=6), thrombocytopenia (n=6), hypotension (n=4), headache (n=4), peripheral edema (n=4), asthenia (n=4), nausea (n=4), anemia (n=4), and neutropenia (n=4).
“For the European experience, there were some differences from the Japanese experience,” Dr Zinzani said in closing. “It was worse in terms of overall response rate—only 11%—but roughly 50% of patients attained at least stable disease. And there was an acceptable safety profile in these really heavily pretreated, relapsed/refractory PTCL patients.”