Seattle Genetics Announces ADCETRIS Supplemental BLA Accepted for Filing by the FDA

Seattle Genetics

announced today that the U.S. Food and Drug Administration (FDA) has accepted for filing a supplement to the Biologics License Application (sBLA) supporting the use of ADCETRIS (brentuximab vedotin) for retreatment and extended duration beyond 16 cycles of therapy in relapsed Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL). The FDA is expected to take action on the application by September 14, 2013. ADCETRIS is an antibody-drug conjugate (ADC) directed to CD30, a defining marker of HL and sALCL, that was granted accelerated approval by the FDA in August 2011 for relapsed HL and relapsed sALCL. “Our goal is to broaden the ADCETRIS U.S. labeling claims to provide both patients and physicians the opportunity to incorporate ADCETRIS into additional HL and sALCL treatment settings,” said Clay B. Siegall, Ph.D., President and Chief Executive Officer of Seattle Genetics. “The FDA's acceptance of our sBLA submission is an important step towards making ADCETRIS available in the retreatment and extended duration setting, and we look forward to the regulatory outcome.” The sBLA is based on results from a phase 2 clinical trial with two treatment arms. One arm evaluated retreatment with ADCETRIS in patients who previously responded to treatment with ADCETRIS, then discontinued treatment and subsequently had disease progression or relapse. The other arm evaluated extended treatment with ADCETRIS beyond 16 cycles of therapy. The sBLA submission includes updated data sets from this phase 2 trial. Preliminary data from this trial were previously reported at the 2011 American Society of Hematology (ASH) Annual Meeting and at the 2012 American Society of Clinical Oncology (ASCO) Annual Meeting. Highlights include: Retreatment: Of 23 evaluable patients who were retreated with ADCETRIS, 70 percent (16 of 23) achieved an objective response, including nine complete remissions and seven partial remissions. Median duration of retreatment objective response was 8.8 months. ADCETRIS was generally well tolerated in the retreatment setting. The most common adverse events were peripheral neuropathy (46 percent), nausea (42 percent), fatigue (38 percent), diarrhea (33 percent) and fever (29 percent), the majority of which were Grade 1 or 2. Extended duration of treatment: Extended treatment data were reported from 17 patients with a median duration of treatment of 17.3 months (approximately 24 cycles of every three-week dosing). The overall objective response rate with extended treatment was 88 percent, including 76 percent complete remissions and 12 percent partial remissions. ADCETRIS was generally well tolerated in this setting, with the most common adverse events being peripheral neuropathy (71 percent), upper respiratory infection (53 percent) and fatigue (47 percent). Adverse events were effectively managed by dose delays and reductions, with less than ten percent of doses delayed or reduced. All events of peripheral neuropathy and upper respiratory infection were Grade 1 and 2 and one patient experienced a Grade 3 fatigue event. ADCETRIS is currently not approved for retreatment and extended duration beyond 16 cycles of therapy in relapsed HL and sALCL. About Lymphoma Lymphoma is a general term for a group of cancers that originate in the lymphatic system. There are two major categories of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma is distinguished from other types of lymphoma by the presence of one characteristic type of cell, known as the Reed-Sternberg cell. The Reed-Sternberg cell generally expresses CD30. Systemic ALCL is an aggressive type of T-cell non-Hodgkin lymphoma that also expresses CD30. About ADCETRIS 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 but to release MMAE upon internalization into CD30-expressing tumor cells. ADCETRIS was granted accelerated approval by the FDA in August 2011 and approval with conditions by Health Canada in February 2013 for two indications: (1) the treatment of patients with HL after failure of autologous stem cell transplant (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 the treatment of adult patients with relapsed or refractory CD30+ Hodgkin lymphoma (HL): (1) following autologous stem cell transplant (ASCT), or (2) following at least two prior therapies when ASCT or multi-agent chemotherapy is not a treatment option. ADCETRIS is indicated for the treatment of adult patients with relapsed or refractory sALCL. See important safety information below. ADCETRIS is being evaluated in more than 20 ongoing clinical trials across both corporate and investigator-sponsored studies. The trials are designed to broadly evaluate the potential of ADCETRIS in earlier lines of its approved indications as well as in many additional types of CD30-positive malignancies, including cutaneous T-cell lymphoma (CTCL), B-cell lymphomas and mature T-cell lymphomas (MTCL). For more information, visit www.clinicaltrials.gov. The clinical trials include: ALCANZA, a phase 3 trial in relapsed CD30-positive CTCL ECHELON-1, a phase 3 frontline trial in HL ECHELON-2, a phase 3 frontline trial in MTCL Phase 2 trial for relapsed or refractory CD30-positive non-Hodgkin lymphomas Phase 2 frontline HL in patients age 60 and older Phase 2 trial for CD30-positive non-lymphoma malignancies Seattle Genetics and Millennium are jointly developing ADCETRIS. Under the terms of the collaboration agreement, Seattle Genetics has U.S. and Canadian commercialization rights and the Takeda Group has rights to commercialize ADCETRIS in the rest of the world. Seattle Genetics and the Takeda Group are funding joint development costs for ADCETRIS on a 50:50 basis, except in Japan, where the Takeda Group is solely responsible for development costs. About Seattle Genetics Seattle Genetics is a biotechnology company focused on the development and commercialization of monoclonal antibody-based therapies for the treatment of cancer. The company's lead program, ADCETRIS (brentuximab vedotin), received accelerated approval from the U.S. Food and Drug Administration in August 2011 and approval with conditions from Health Canada in February 2013 for two indications. In addition, under a collaboration with Millennium: The Takeda Oncology Company, ADCETRIS received conditional approval from the European Commission in October 2012. Seattle Genetics also has four other clinical-stage ADC programs: SGN-75, ASG-5ME, ASG-22ME and SGN-CD19A. Seattle Genetics has collaborations for its ADC technology with a number of leading biotechnology and pharmaceutical companies, including AbbVie, Agensys (an affiliate of Astellas), Bayer, Celldex, Daiichi Sankyo, Genentech, GlaxoSmithKline, Millennium, Pfizer and Progenics, as well as ADC co-development agreements with Agensys and Genmab. More information can be found at www.seattlegenetics.com. U.S. Important Safety Information BOXED WARNING Progressive multifocal leukoencephalopathy (PML): JC virus infection resulting in PML and death can occur in patients receiving ADCETRIS. Contraindication: Concomitant use of ADCETRIS and bleomycin is contraindicated due to pulmonary toxicity. Warnings and Precautions: Peripheral neuropathy: ADCETRIS treatment causes a peripheral neuropathy that is predominantly sensory. Cases of peripheral motor neuropathy have also been reported. ADCETRIS-induced peripheral neuropathy is cumulative. Treating physicians should monitor patients for symptoms of neuropathy, such as hypoesthesia, hyperesthesia, paresthesia, discomfort, a burning sensation, neuropathic pain or weakness and institute dose modifications accordingly. Infusion reactions: Infusion-related reactions, including anaphylaxis, have occurred with ADCETRIS. Monitor patients during infusion. If an infusion reaction occurs, the infusion should be interrupted and appropriate medical management instituted. If anaphylaxis occurs, the infusion should be immediately and permanently discontinued and appropriate medical management instituted. Neutropenia: Monitor complete blood counts prior to each dose of ADCETRIS and consider more frequent monitoring for patients with Grade 3 or 4 neutropenia. If Grade 3 or 4 neutropenia develops, manage by dose delays, reductions or discontinuation. Prolonged (≥1 week) severe neutropenia can occur with ADCETRIS. Tumor lysis syndrome: Patients with rapidly proliferating tumor and high tumor burden are at risk of tumor lysis syndrome and these patients should be monitored closely and appropriate measures taken. Progressive multifocal leukoencephalopathy (PML): JC virus infection resulting in PML and death has been reported in ADCETRIS-treated patients. In addition to ADCETRIS therapy, other possible contributory factors include prior therapies and underlying disease that may cause immunosuppression. Consider the diagnosis of PML in any patient presenting with new-onset signs and symptoms of central nervous system abnormalities. Evaluation of PML includes, but is not limited to, consultation with a neurologist, brain MRI, and lumbar puncture or brain biopsy. Hold ADCETRIS if PML is suspected and discontinue ADCETRIS if PML is confirmed. Stevens-Johnson syndrome: Stevens-Johnson syndrome has been reported with ADCETRIS. If Stevens-Johnson syndrome occurs, discontinue ADCETRIS and administer appropriate medical therapy. Use in pregnancy: Fetal harm can occur. Pregnant women should be advised of the potential hazard to the fetus. Adverse Reactions: ADCETRIS was studied as monotherapy in 160 patients in two phase 2 trials. Across both trials, the most common adverse reactions (≥20%), regardless of causality, were neutropenia, peripheral sensory neuropathy, fatigue, nausea, anemia, upper respiratory tract infection, diarrhea, pyrexia, rash, thrombocytopenia, cough and vomiting. Drug Interactions: Patients who are receiving strong CYP3A4 inhibitors concomitantly with ADCETRIS should be closely monitored for adverse reactions. For additional important safety information, including Boxed WARNING, please see the full U.S. prescribing information for ADCETRIS at www.seattlegenetics.com or www.ADCETRIS.com. Certain of the statements made in this press release are forward looking, such as those, among others, relating to the company's expectations for the addition of the label claims sought in the sBLA. Factors that may cause such a difference include that the submitted data are not sufficient to provide for approval of the claims in the sBLA. More information about the risks and uncertainties faced by Seattle Genetics is contained in the company's 10-Q for the quarter ended March 31, 2013, 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.