Seattle Genetics, Inc., a biotechnology company, and Takeda Pharmaceutical Company Limited announced four-year overall survival (OS) data from the Adcetris (brentuximab vedotin) pivotal phase 2 clinical trial in relapsed or refractory systemic anaplastic large cell lymphoma (ALCL).

Adcetris is an antibody-drug conjugate (ADC) directed to CD30, which is expressed in classical Hodgkin lymphoma (HL) and systemic ALCL, a type of T-cell lymphoma. At a median follow up of 46.3 months, the estimated four-year survival rate was 64 percent.

The data were presented at the 56th American Society of Hematology (ASH) Annual Meeting and Exposition taking place in San Francisco, California.

“Historical outcomes for patients with relapsed T-cell lymphoma, including systemic ALCL have been poor, with a median overall survival of 5.5 months and a median progression-free survival of 3.1 months. The four-year survival data from the pivotal trial in systemic ALCL demonstrate Adcetris’ activity in the treatment of this disease, with an estimated four-year survival rate of 64 percent and a median progression-free survival of 20 months,” said Clay B. Siegall, Ph.D., president and chief executive officer of Seattle Genetics. “These encouraging data show durable, long-term responses in the relapsed systemic ALCL treatment setting and support the evaluation of Adcetris in earlier lines of therapy, including in the ongoing phase 3 ECHELON-2 clinical trial in frontline mature T-cell lymphoma.”

“The data estimate that more than 60 per cent of the relapsed or refractory ALCL patients treated with Adcetris in this study are alive at four years, which may positively redefine outcome expectations in this difficult to treat cancer,” said Dirk Huebner, M.D., senior medical director, oncology Therapeutic Area Unit, Takeda Pharmaceutical Company. “The fact that a third of all patients treated in the trial remain in complete remission with no evidence of disease after a median follow up of 46 months suggests the difference Adcetris can make in this disease.”

A pivotal, single-arm clinical trial was conducted in 58 relapsed or refractory systemic ALCL patients to assess the efficacy and safety of single-agent Adcetris. In addition, the trial was designed to determine duration of response, progression-free survival (PFS) and overall survival (OS). Patients received 1.8 milligrams per kilogram (mg/kg) of Adcetris administered through a 30-minute intravenous infusion every three weeks for up to 16 cycles. As previously reported, 86 per cent of patients on the trial achieved an objective response, including 59 per cent with a complete response (CR) and 28 per cent with a partial response (PR).

Data from long-term patient follow up in this pivotal trial will be highlighted by Barbara Pro, M.D., Thomas Jefferson University, and include: After a median observation time of 46.3 months from the first dose of Adcetris, the median OS was 55.1 months and the estimated four-year OS was 64 percent; The median PFS per investigator was 20.0 months; Nineteen of 38 patients (50 percent) who achieved a CR on study per investigator assessment remained in remission at the time of last follow-up; for all patients who achieved a CR, median OS and PFS had not yet been reached;For the 16 CR patients who received a consolidative transplant (either allogeneic or autologous stem cell transplant), neither median PFS nor OS had been reached; For the 22 CR patients who did not receive a consolidative transplant, median PFS was 39.4 months and median OS had not yet been reached. Eight CR patients remained in remission without receipt of any subsequent anti-lymphoma therapy following Adcetris.

The most common adverse events of any grade were peripheral neuropathy (57 per cent), nausea (40 per cent), fatigue (38 per cent), pyrexia (34 per cent) and diarrhea (29 per cent).

The most common Grade 3 or 4 adverse events occurring in at least five percent of patients were neutropenia (21 per cent), peripheral neuropathy (17 per cent), thrombocytopenia (14 per cent), anemia (seven per cent) and recurrent ALCL (five per cent).

Adcetris (brentuximab vedotin) is an ADC comprising an anti-CD30 monoclonal antibody attached by a protease-cleavable linker to a microtubule disrupting agent, monomethyl auristatin E (MMAE), utilizing Seattle Genetics’ proprietary technology. The ADC employs a linker system that is designed to be stable in the bloodstream and release MMAE upon internalization into CD30-expressing tumor cells.

Adcetris for intravenous injection received accelerated approval from the US Food and Drug Administration and approval with conditions from Health Canada for two indications: (1) the treatment of patients with HL after failure of ASCT or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not ASCT candidates, and (2) the treatment of patients with sALCL after failure of at least one prior multi-agent chemotherapy regimen. The indications for Adcetris are based on response rate. There are no data available demonstrating improvement in patient-reported outcomes or survival with Adcetris.

Adcetris was granted conditional marketing authorization by the European Commission in October 2012 for two indications: (1) for the treatment of adult patients with relapsed or refractory CD30-positive HL following ASCT, or following at least two prior therapies when ASCT or multi-agent chemotherapy is not a treatment option, and (2) the treatment of adult patients with relapsed or refractory sALCL. Adcetris has received marketing authorization by regulatory authorities in 45 countries.

Seattle Genetics and Takeda are jointly developing Adcetris. Under the terms of the collaboration agreement, Seattle Genetics has US and Canadian commercialization rights and Takeda has rights to commercialize Adcetris in the rest of the world. Seattle Genetics and Takeda are funding joint development costs for Adcetris on a 50:50 basis, except in Japan where Takeda will be solely responsible for development costs.

Seattle Genetics is a biotechnology company focused on the development and commercialization of innovative antibody-based therapies for the treatment of cancer.

The Takeda Oncology Business Unit, headquartered in Cambridge, MA, is co-located with the leadership of Takeda’s globally-integrated oncology research and development enterprise, overseen by the Oncology Therapeutic Area Unit. Takeda Oncology delivers novel medicines to patients with cancer worldwide through its commitment to science, breakthrough innovation and passion for improving the lives of patients. Takeda Oncology was formerly known as Millennium: The Takeda Oncology Company.