Seattle Genetics Announces Health Canada Approval of ADCETRIS® (Brentuximab Vedotin) in Combination with Chemotherapy in Frontline CD30-Expressing Peripheral T-Cell Lymphoma

– Approval of Supplemental New Drug Submission for ADCETRIS in Combination with CHP Chemotherapy in Frontline CD30-Expressing Peripheral T-Cell Lymphoma based on Positive Phase 3 ECHELON-2 Clinical Trial Results –

BOTHELL, Wash.–(BUSINESS WIRE)–Seattle Genetics, Inc. (Nasdaq:SGEN) today announced that Health Canada has approved the supplemental New Drug Submission that expands the use of ADCETRIS (brentuximab vedotin) in combination with CHP (cyclophosphamide, doxorubicin, prednisone) chemotherapy for the treatment of previously untreated adult patients with systemic anaplastic large cell lymphoma (sALCL), peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) or angioimmunoblastic T-cell lymphoma (AITL), whose tumours express CD30. The approval is based on positive results of the phase 3 ECHELON-2 clinical trial that compared ADCETRIS plus CHP to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone). Health Canada granted a Priority Review Designation for this submission. ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30, which is expressed on the surface of several types of PTCL.

“The Health Canada approval of ADCETRIS (brentuximab vedotin) in combination with CHP chemotherapy in newly diagnosed CD30-expressing peripheral T-cell lymphoma represents the first major advance for Canadian patients with PTCL in decades,” said Kerry Savage, M.D., Medical Oncologist at the BC Cancer Agency, Professor of Medicine at the University of British Columbia and investigator on the ECHELON-2 clinical trial. “The approval is based on the ECHELON-2 clinical trial that demonstrated ADCETRIS (brentuximab vedotin) plus CHP regimen was superior for both progression-free survival and all key secondary endpoints, including overall survival, when compared to the standard of care CHOP chemotherapy.”

“The current standard of care for initial treatment of peripheral T-cell lymphoma is multi-agent chemotherapy, which results in low complete remission rates and poor progression-free and overall survival. ECHELON-2 is the first randomized trial to demonstrate an overall survival benefit over established standard therapy, making it a meaningful advance in the treatment of these rare lymphomas,” said Roger Dansey, M.D., Chief Medical Officer at Seattle Genetics. “With this new indication for ADCETRIS, physicians and eligible patients in Canada now have access to this important new regimen for treating frontline CD30-expressing peripheral T-cell lymphoma, another milestone supporting our plans to continue to expand ADCETRIS globally to patients in need.”

In May 2019, Health Canada approved the supplemental New Drug Submission that expanded the use of ADCETRIS in combination with AVD (Adriamycin, vinblastine and dacarbazine) chemotherapy in patients with previously untreated Stage IV Hodgkin lymphoma (HL) based on the results of the phase 3 ECHELON-1 clinical trial.

About T-Cell Lymphomas

There are more than 60 subtypes of non-Hodgkin lymphomas which are broadly divided into two major groups: B-cell lymphomas, which develop from abnormal B-lymphocytes, and T-cell lymphomas, which develop from abnormal T-lymphocytes. There are many different forms of T-cell lymphomas, some of which are extremely rare. T-cell lymphomas can be aggressive (fast-growing) or indolent (slow-growing). PTCL accounts for approximately 10 percent of non-Hodgkin lymphoma cases in the U.S. and Europe and may be as high as 24 percent in parts of Asia.

About ADCETRIS

ADCETRIS is being evaluated broadly in more than 70 clinical trials in CD30-expressing lymphomas. These include three completed phase 3 trials: ECHELON-2 trial in frontline peripheral T-cell lymphomas, ECHELON-1 in previously untreated Hodgkin lymphoma, and ALCANZA in cutaneous T-cell lymphoma.

ADCETRIS 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 but to release MMAE upon internalization into CD30-expressing tumor cells.

ADCETRIS injection for intravenous infusion has received FDA approval for six indications in adult patients with: (1) previously untreated systemic anaplastic large cell lymphoma (sALCL) or other CD30-expressing peripheral T-cell lymphomas (PTCL), including angioimmunoblastic T-cell lymphoma and PTCL not otherwise specified, in combination with cyclophosphamide, doxorubicin, and prednisone, (2) previously untreated Stage III or IV classical Hodgkin lymphoma (cHL), in combination with doxorubicin, vinblastine, and dacarbazine, (3) cHL at high risk of relapse or progression as post-autologous hematopoietic stem cell transplantation (auto-HSCT) consolidation, (4) cHL after failure of auto-HSCT or failure of at least two prior multi-agent chemotherapy regimens in patients who are not auto-HSCT candidates, (5) sALCL after failure of at least one prior multi-agent chemotherapy regimen, and (6) primary cutaneous anaplastic large cell lymphoma (pcALCL) or CD30-expressing mycosis fungoides (MF) who have received prior systemic therapy.

Health Canada granted ADCETRIS approval with conditions in 2013 for patients with (1) HL after failure of autologous stem cell transplant (ASCT) or after failure of at least two multi-agent chemotherapy regimens in patients who are not ASCT candidates and (2) sALCL after failure of at least one multi-agent chemotherapy regimen. Non-conditional approval was granted for (3) post-ASCT consolidation treatment of patients with HL at increased risk of relapse or progression in 2017, (4) adult patients with pcALCL or CD30-expressing MF who have received prior systemic therapy in 2018, (5) for previously untreated patients with Stage IV HL in combination with doxorubicin, vinblastine, and dacarbazine in 2019, and (6) for previously untreated adult patients with sALCL, peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) or angioimmunoblastic T-cell lymphoma (AITL), whose tumors express CD30, in combination with cyclophosphamide, doxorubicin, prednisone in 2019.

ADCETRIS received conditional marketing authorization from the European Commission in October 2012. The approved indications in Europe are: (1) for the treatment of adult patients with relapsed or refractory CD30-positive Hodgkin lymphoma following ASCT, or following at least two prior therapies when ASCT or multi-agent chemotherapy is not a treatment option, (2) for the treatment of adult patients with relapsed or refractory sALCL, (3) for the treatment of adult patients with CD30-positive Hodgkin lymphoma at increased risk of relapse or progression following ASCT, (4) for the treatment of adult patients with CD30-positive cutaneous T-cell lymphoma (CTCL) after at least one prior systemic therapy and (5) for the treatment of adult patients with previously untreated CD30-positive Stage IV Hodgkin lymphoma in combination with AVD (Adriamycin^®, vinblastine and dacarbazine).

ADCETRIS has received marketing authorization by regulatory authorities in 73 countries for relapsed or refractory Hodgkin lymphoma and sALCL. See select important safety information, including Boxed Warning, below.

Seattle Genetics and Takeda are jointly developing ADCETRIS. Under the terms of the collaboration agreement, Seattle Genetics has U.S. 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 is solely responsible for development costs.

About Seattle Genetics

Seattle Genetics, Inc. is an emerging multi-product, global biotechnology company that develops and commercializes transformative therapies targeting cancer to make a meaningful difference in people’s lives. ADCETRIS^® (brentuximab vedotin) utilizes the company’s industry-leading antibody-drug conjugate (ADC) technology and is currently approved for the treatment of multiple CD30-expressing lymphomas. Beyond ADCETRIS, the company has a late-stage pipeline including enfortumab vedotin for metastatic urothelial cancer, currently being reviewed for approval by the FDA, and tisotumab vedotin in clinical trials for metastatic cervical cancer, which utilize our proprietary ADC technology. In addition, tucatinib, a small molecule tyrosine kinase inhibitor, is in late-stage development for HER2-positive metastatic breast cancer and in clinical development for metastatic colorectal cancer. We are also leveraging our expertise in empowered antibodies to build a portfolio of proprietary immuno-oncology agents in clinical trials targeting hematologic malignancies and solid tumors. The company is headquartered in Bothell, Washington, and has a European office in Switzerland. For more information on our robust pipeline, visit www.seattlegenetics.com and follow @SeattleGenetics on Twitter.

ADCETRIS (brentuximab vedotin) U.S. Important Safety Information

BOXED WARNING

PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY (PML): JC virus infection resulting in PML and death can occur in ADCETRIS-treated patients.

Contraindication

ADCETRIS concomitant with bleomycin due to pulmonary toxicity (e.g., interstitial infiltration and/or inflammation).

Warnings and Precautions

• Peripheral neuropathy (PN): ADCETRIS causes PN that is predominantly sensory. Cases of motor PN have also been reported. ADCETRIS-induced PN is cumulative. Monitor for symptoms such as hypoesthesia, hyperesthesia, paresthesia, discomfort, a burning sensation, neuropathic pain, or weakness. Institute dose modifications accordingly.
• Anaphylaxis and infusion reactions: Infusion-related reactions (IRR), including anaphylaxis, have occurred with ADCETRIS. Monitor patients during infusion. If an IRR occurs, interrupt the infusion and institute appropriate medical management. If anaphylaxis occurs, immediately and permanently discontinue the infusion and administer appropriate medical therapy. Premedicate patients with a prior IRR before subsequent infusions. Premedication may include acetaminophen, an antihistamine, and a corticosteroid.
• Hematologic toxicities: Fatal and serious cases of febrile neutropenia have been reported with ADCETRIS. Prolonged (≥1 week) severe neutropenia and Grade 3 or 4 thrombocytopenia or anemia can occur with ADCETRIS. Administer G-CSF primary prophylaxis beginning with Cycle 1 for patients who receive ADCETRIS in combination with chemotherapy for previously untreated Stage III/IV cHL or previously untreated PTCL. Monitor complete blood counts prior to each ADCETRIS dose. Monitor more frequently for patients with Grade 3 or 4 neutropenia. Monitor patients for fever. If Grade 3 or 4 neutropenia develops, consider dose delays, reductions, discontinuation, or G-CSF prophylaxis with subsequent doses.
• Serious infections and opportunistic infections: Infections such as pneumonia, bacteremia, and sepsis or septic shock (including fatal outcomes) have been reported in ADCETRIS-treated patients. Closely monitor patients during treatment for bacterial, fungal, or viral infections.
• Tumor lysis syndrome: Closely monitor patients with rapidly proliferating tumor and high tumor burden.
• Increased toxicity in the presence of severe renal impairment: The frequency of ≥Grade 3 adverse reactions and deaths was greater in patients with severe renal impairment compared to patients with normal renal function. Avoid use in patients with severe renal impairment.
• Increased toxicity in the presence of moderate or severe hepatic impairment: The frequency of ≥Grade 3 adverse reactions and deaths was greater in patients with moderate or severe hepatic impairment compared to patients with normal hepatic function. Avoid use in patients with moderate or severe hepatic impairment.
• Hepatotoxicity: Fatal and serious cases have occurred in ADCETRIS-treated patients. Cases were consistent with hepatocellular injury, including elevations of transaminases and/or bilirubin, and occurred after the first ADCETRIS dose or rechallenge. Preexisting liver disease, elevated baseline liver enzymes, and concomitant medications may increase the risk. Monitor liver enzymes and bilirubin. Patients with new, worsening, or recurrent hepatotoxicity may require a delay, change in dose, or discontinuation of ADCETRIS.
• PML: Fatal cases of JC virus infection resulting in PML and death have been reported in ADCETRIS-treated patients. First onset of symptoms occurred at various times from initiation of ADCETRIS therapy, with some cases occurring within 3 months of initial exposure. In addition to ADCETRIS therapy, other possible contributory factors include prior therapies and underlying disease that may cause immunosuppression. Consider PML diagnosis in patients with new-onset signs and symptoms of central nervous system abnormalities. Hold ADCETRIS if PML is suspected and discontinue ADCETRIS if PML is confirmed.
• Pulmonary toxicity: Fatal and serious events of noninfectious pulmonary toxicity including pneumonitis, interstitial lung disease, and acute respiratory distress syndrome have been reported. Monitor patients for signs and symptoms, including cough and dyspnea. In the event of new or worsening pulmonary symptoms, hold ADCETRIS dosing during evaluation and until symptomatic improvement.
• Serious dermatologic reactions: Fatal and serious cases of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported with ADCETRIS. If SJS or TEN occurs, discontinue ADCETRIS and administer appropriate medical therapy.
• Gastrointestinal (GI) complications: Fatal and serious cases of acute pancreatitis have been reported. Other fatal and serious GI complications include perforation, hemorrhage, erosion, ulcer, intestinal obstruction, enterocolitis, neutropenic colitis, and ileus. Lymphoma with preexisting GI involvement may increase the risk of perforation. In the event of new or worsening GI symptoms, including severe abdominal pain, perform a prompt diagnostic evaluation and treat appropriately.
• Hyperglycemia: Serious cases, such as new-onset hyperglycemia, exacerbation of preexisting diabetes mellitus, and ketoacidosis (including fatal outcomes) have been reported with ADCETRIS. Hyperglycemia occurred more frequently in patients with high body mass index or diabetes. Monitor serum glucose and if hyperglycemia develops, administer antihyperglycemic medications as clinically indicated.
• Embryo-fetal toxicity: Based on the mechanism of action and animal studies, ADCETRIS can cause fetal harm. Advise females of reproductive potential of the potential risk to the fetus, and to avoid pregnancy during ADCETRIS treatment and for at least 6 months after the final dose of ADCETRIS.

Most Common (≥20% in any study) Adverse Reactions: Peripheral neuropathy, fatigue, nausea, diarrhea, neutropenia, upper respiratory tract infection, pyrexia, constipation, vomiting, alopecia, decreased weight, abdominal pain, anemia, stomatitis, lymphopenia and mucositis.

Drug Interactions

Concomitant use of strong CYP3A4 inhibitors or inducers has the potential to affect the exposure to monomethyl auristatin E (MMAE).

Use in Specific Populations

Moderate or severe hepatic impairment or severe renal impairment: MMAE exposure and adverse reactions are increased. Avoid use.

Advise males with female sexual partners of reproductive potential to use effective contraception during ADCETRIS treatment and for at least 6 months after the final dose of ADCETRIS.

Advise patients to report pregnancy immediately and avoid breastfeeding while receiving ADCETRIS.

Please see the full Prescribing Information, including BOXED WARNING, for ADCETRIS here.

Forward-Looking Statements

Certain of the statements made in this press release are forward looking, such as those, among others, relating to the potential utilization of ADCETRIS (brentuximab vedotin) for previously untreated adult patients with systemic anaplastic large cell lymphoma, peripheral T-cell lymphoma-not otherwise specified or angioimmunoblastic T-cell lymphoma, whose tumours express CD30 in Canada and the therapeutic potential of ADCETRIS in this indication. Actual results or developments may differ materially from those projected or implied in these forward-looking statements due to factors such as utilization and adoption of the approved treatment regimen by prescribing physicians, competitive conditions including the availability of alternative treatment regimens, the availability and extent of reimbursement, the risk of adverse events, and adverse regulatory action. More information about the risks and uncertainties faced by Seattle Genetics is contained under the caption “Risk Factors” included in the company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2019 filed with the Securities and Exchange Commission. Seattle Genetics disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

Contacts

Media:

Monique Greer

(425) 527-4641

[email protected]

Investors:

Peggy Pinkston

(425) 527-4160

[email protected]