SAN DIEGO – First-line treatment of peripheral T-cell lymphomas (PTCL) with a quartet of drugs substituting Adcetris (brentuximab vedotin) for Oncovin (vincristine) in the decades-old standard of care for the disease, CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone), proved superior on both progression-free survival and overall survival, according to full data reported Tuesday by Seattle Genetics Inc. and partner Takeda Pharmaceutical Co. Ltd.

The phase trial, called Echelon-2, started more than five years ago. It was designed to "redefine front-line therapy in T-cell lymphoma," Seattle Genetics CEO and founder Clay Siegall told BioWorld.

Top-line data from the study was first revealed Oct. 1. In contacting the FDA shortly thereafter, Siegall said his team asked about the agency's recently launched Real-Time Oncology Review pilot program. After being invited to participate in the program, a string of daily exchanges with reviewers followed, often including questions for which they sought 24-hour turnaround on answers. "We worked and worked and worked... evenings, weekends, constantly," Siegall said. "And they were working, too. It was impressive," he said.

Seagen submitted a supplemental new drug application about five weeks later, leading to an approval to market Adcetris for the treatment of adults with previously untreated systemic anaplastic large-cell lymphoma or other CD30-expressing PTCL, including angioimmunoblastic T-cell lymphoma and PTCL not otherwise specified, in combination with CHP (cyclophosphamide, doxorubicin and prednisone).

Full results of the study, presented Tuesday during the American Society of Hematology meeting, showed that combining Adcetris with CHP led to a 29 percent reduction in the risk of progression, death or need for additional cancer therapy for residual or progressive disease.

After a median follow-up time of 36.2 months, the median PFS in the Adcetris plus CHP arm was 48.2 months vs. 20.8 months in the CHOP-based control arm. The three-year PFS was 57.1 percent for Adcetris plus CHP compared to 44.4 percent in the control arm.

Investigators also recorded a 34 percent reduction in the risk of death for patients taking the Adcetris-containing regimen. After a median follow-up of 42.1 months, the median OS was not reached for either arm of the study. The estimated three-year OS was 76.8 percent for Adcetris plus CHP compared to 69.1 percent for CHOP.

Bothell, Wash.-based Seattle Genetics and Takeda, of Osaka, Japan, are jointly developing Adcetris. Seagen has U.S. and Canadian commercialization rights and Takeda has rights to commercialize Adcetris in the rest of the world.