– Updated phase 2 data results presented for ADCETRIS in combination with immune therapy nivolumab and doxorubicin and dacarbazine chemotherapy –

– Regimen well-tolerated with fewer than half of patients developing primarily low-grade peripheral neuropathy and no cases of febrile neutropenia –

BOTHELL, Wash.--(BUSINESS WIRE)-- Seagen Inc. (NASDAQ: SGEN) today announced updated efficacy and safety results from Part C of a phase 2 single-arm trial (SGN35-027) evaluating the antibody-drug conjugate ADCETRIS® (brentuximab vedotin) in combination with the PD-1 inhibitor nivolumab and standard chemotherapy agents doxorubicin and dacarbazine (AN+AD) for the frontline treatment of patients with early-stage classical Hodgkin lymphoma (cHL). Data results will be presented at the 17th International Conference on Malignant Lymphoma (ICML) in Lugano, SwitzerlandJune 13-17.

Also, to be presented in a late-breaking session, are three-year results from a 1,500-patient phase 3 trial from the German Hodgkin Study Group (HD21) evaluating non-inferiority efficacy and potential for reduced toxicity of an ADCETRIS regimen (BrECADD) compared to the highly efficacious yet chemotherapy intensive escalated BEACOPP regimen, commonly used outside of the U.S. The study will be presented on June 17, 2023.

ADCETRIS + AVD chemotherapy (Adriamycin, vinblastine, dacarbazine) is a U.S. standard of care in advanced-stage cHL based on national treatment guidelines and is the only targeted therapy inclusive regimen that has a proven statistically significant overall survival benefit at 6-years of follow-up, reducing risk of death by 41% for these patients.i,ii ADCETRIS is approved for seven indications in the U.S. and five indications in Europe, where Takeda has commercialization rights.

“With teens and young adults primarily impacted by Hodgkin lymphoma, our goal is to develop curative treatments that improve survival while also reducing toxicity,” said Jeremy Abramson, MD, Director, Jon and Jo Ann Hagler Center for Lymphoma at Massachusetts General Hospital and principal investigator of the trial. “The targeted agents of brentuximab vedotin and nivolumab have distinct mechanisms of action and demonstrated promising activity and safety in this early study; the omission of bleomycin and vinblastine chemotherapy likely contributed to the absence of certain adverse events.”

“We are encouraged by the promising clinical outcomes of an ADCETRIS plus nivolumab combination with reduced chemotherapy as we seek to maximize efficacy and improve tolerability in both early- and late-stage classical Hodgkin lymphoma,” said Roger Dansey, President of Research and Development and Chief Medical Officer at Seagen.

New Results Presented from SGN35-027

Of 154 patients with early-stage disease in Part C of the study, 150 were included at the time of efficacy assessment, showing:

• A 98% ORR (95% CI: 94.3, 99.6) and a 93% CR rate (95% CI: 87.3, 96.3) at end of treatment (EOT).
• Follow-up is ongoing and progression-free survival (PFS) results are not yet available.
• The most frequently reported treatment-related treatment-emergent adverse events (TRAEs) of any grade occurring in more than 30 percent of patients were nausea (65%), peripheral sensory neuropathy (47%) and fatigue (44%).
• Peripheral sensory neuropathy was primarily low grade (3% Grade ≥3).
• There were no cases of febrile neutropenia.
• Immune-mediated AEs observed to date are consistent with the individual safety profile of nivolumab.
• There were no grade 5 adverse events.

Updated data results from Part B of the study in patients with advanced-stage disease (n=57) were presented at the European Hematology Association 2023 Congress in Frankfurt, GermanyJune 8-11, which showed an estimated 95% 12-month PFS rate and 93% 18-month PFS rate, an ORR of 95% and CR rate of 89% at EOT. The most frequently reported TRAEs of any grade occurring in more than 30 percent of patients were nausea (65%), fatigue (49%), peripheral sensory neuropathy (44%) and alopecia (35%).

Please see Important Safety Information, including a BOXED WARNING for progressive multifocal leukoencephalopathy (PML), for ADCETRIS below.

About the SGN35-027 Clinical Study

SGN35-027 is an ongoing open-label, multiple part, multicenter, phase 2 clinical trial evaluating two different brentuximab vedotin treatment combinations in patients with advanced and early-stage cHL. The trial includes three parts (Parts A, B, and C). Part A is evaluating the combination of brentuximab vedotin and doxorubicin, vinblastine, and dacarbazine (A+AVD) with primary granulocyte-colony stimulating factor (G-CSF) prophylaxis, while Parts B and C are evaluating brentuximab vedotin in combination with nivolumab, doxorubicin, and dacarbazine (AN+AD) as a first-line treatment in advanced and early-stage disease, respectively. Part B is evaluating the combination in patients with stage II bulky (mediastinal mass ≥10 cm), stage III or IV cHL. Part C is evaluating the combination in patients with stage I or II cHL without bulky mediastinal disease (