Seagen Acquisition Yields Positive Adcetris Phase III Results for Pfizer in DLBCL

Pfizer has announced the positive outcomes of the Phase III ECHELON-3 clinical trial, which evaluated the efficacy of the antibody-drug conjugate (ADC) Adcetris (brentuximab vedotin) in combination with lenalidomide and rituximab for the treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL). The study showed that the treatment significantly improved the overall survival of patients compared to a placebo group receiving the same combination of lenalidomide and rituximab. Although specific data were not disclosed, Pfizer highlighted that the results were both statistically significant and clinically meaningful.

The Adcetris combination also yielded positive results in secondary endpoints such as overall response rate and progression-free survival. The safety profile of Adcetris was consistent with previous findings, demonstrating its tolerability and expected adverse events.

Roger Dansey, Pfizer's chief development officer of oncology, emphasized the potential of Adcetris to meet a significant unmet need in patients with relapsed or refractory DLBCL, regardless of CD30 expression. The study's inclusion of heavily pre-treated patients, some of whom had previously received CAR-T therapy, makes the results particularly promising.

Adcetris, which targets the CD30 surface protein commonly found in certain blood cancers, was originally developed by Seagen in partnership with Takeda. It contains a toxic payload, monomethyl auristatin E, designed to be released within cancer cells to induce cell death. Pfizer obtained rights to Adcetris in March 2023 through its acquisition of Seagen for $43 billion.

Initially approved in 2011 for Hodgkin lymphoma and systemic anaplastic large cell lymphoma, Adcetris has since gained additional approvals for various treatment settings and patient populations. Pfizer and its partners are actively developing Adcetris for other lymphoma subtypes, peripheral T-cell lymphoma, non-small cell lung cancer, and melanoma.

The successful trial results will bolster Pfizer's expertise in ADC technology and expand its presence in this therapeutic area. The company has recently outlined its oncology strategy, focusing on four key cancer types, including hematologic malignancies such as lymphomas and multiple myeloma. Pfizer aims to increase its biologics business to account for approximately 65% of its cancer franchise by 2030, up from the current 6%. The acquisition of Seagen, with its robust ADC portfolio, is a significant step towards achieving this goal.

Additionally, Pfizer has signed a potential $1.05 billion contract with Nona Biosciences to develop an early-stage mesothelin-targeting ADC, HBM9033, for solid tumors, further expanding its pipeline in the biologics and ADC space.