Companies to Co-Develop and Co-Commercialize Seattle Genetics’ Antibody-Drug Conjugate Ladiratuzumab Vedotin Globally; Merck to Acquire $1 Billion Equity Stake in Seattle Genetics Common Stock

Companies Enter Exclusive License and Co-Development Agreement to Accelerate Global Reach of TUKYSA for HER2-Postive Cancers in Regions Outside the United States, Canada and Europe

BOTHELL, WA & KENILWORTH, NJ, USA I September 14, 2020 I Seattle Genetics, Inc. (Nasdaq: SGEN) and Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced two new strategic oncology collaborations.

The companies will globally develop and commercialize Seattle Genetics’ ladiratuzumab vedotin, an investigational antibody-drug conjugate (ADC) targeting LIV-1, which is currently in phase 2 clinical trials for breast cancer and other solid tumors. The collaboration will pursue a broad joint development program evaluating ladiratuzumab vedotin as monotherapy and in combination with Merck’s anti-PD-1 therapy KEYTRUDA® (pembrolizumab) in triple-negative breast cancer, hormone receptor-positive breast cancer and other LIV-1-expressing solid tumors. Under the terms of the agreement, Seattle Genetics will receive a $600 million upfront payment and Merck will make a $1.0 billion equity investment in 5.0 million shares of Seattle Genetics common stock at a price of $200 per share. In addition, Seattle Genetics is eligible for progress-dependent milestone payments of up to $2.6 billion.

Separately, Seattle Genetics has granted Merck an exclusive license to commercialize TUKYSA® (tucatinib), a small molecule tyrosine kinase inhibitor, for the treatment of HER2-positive cancers, in Asia, the Middle East and Latin America and other regions outside of the U.S., Canada and Europe. Seattle Genetics will receive $125 million from Merck as an upfront payment and is eligible for progress-dependent milestones of up to $65 million.

“Collaborating with Merck on ladiratuzumab vedotin will allow us to accelerate and broaden its development program in breast cancer and other solid tumors, including in combination with Merck’s KEYTRUDA, while also positioning us to leverage our U.S. and European commercial operations,” said Clay Siegall, Ph.D., President and Chief Executive Officer of Seattle Genetics. “The strategic collaboration for TUKYSA will help us reach more patients globally and benefit from the established commercial strength of one of the world’s premier pharmaceutical companies.”

“These two strategic collaborations will enable us to further diversify Merck’s broad oncology portfolio and pipeline, and to continue our efforts to extend and improve the lives of as many patients with cancer as possible,” said Dr. Roger M. Perlmutter, President, Merck Research Laboratories. “We look forward to working with the team at Seattle Genetics to advance the clinical program for ladiratuzumab vedotin, which has shown compelling signals of efficacy in early studies, and to bring TUKYSA to even more patients with cancer around the world.”

Ladiratuzumab Vedotin Collaboration Details

Under the terms of the agreement, Seattle Genetics and Merck will collaborate and equally share costs on the global development of ladiratuzumab vedotin and other LIV-1-targeting ADCs. The companies have agreed to jointly develop and share future costs and profits for ladiratuzumab vedotin on a 50:50 basis worldwide. Merck will pay Seattle Genetics $600 million upfront and make a $1.0 billion equity investment in 5.0 million shares of Seattle Genetics common stock at a price of $200 per share. In addition, Seattle Genetics will be eligible to receive up to $2.6 billion in milestone payments, including $850 million in development milestones and $1.75 billion in sales milestones.

The companies will jointly develop and commercialize ladiratuzumab vedotin and equally share profits worldwide. The companies will co-commercialize in the U.S. and Europe. Seattle Genetics will be responsible for marketing applications for approval in the U.S. and Canada, and will record sales in the U.S., Canada and Europe. Merck will be responsible for marketing applications for approval in Europe and in countries outside the U.S. and Canada, and will record sales in countries outside the U.S., Europe and Canada. Including the upfront payment, equity investment proceeds and potential milestone payments, Seattle Genetics is eligible to receive up to $4.2 billion.

The closing of the equity investment is contingent on completion of review under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR Act).

TUKYSA Collaboration Details

Under the terms of the agreement, Merck has been granted exclusive rights to commercialize TUKYSA in Asia, the Middle East and Latin America and other regions outside of the U.S., Canada and Europe. Seattle Genetics retains commercial rights and will record sales in the U.S., Canada and Europe. Merck will be responsible for marketing applications for approval in its territory, supported by the positive results from the HER2CLIMB clinical trial.

Merck will also co-fund a portion of the TUKYSA global development plan, which encompasses several ongoing and planned trials across HER2-positive cancers, including breast, colorectal, gastric and other cancers set forth in a global product development plan. Seattle Genetics will continue to lead ongoing TUKYSA global development planning and operational execution. Merck will solely fund and conduct country-specific clinical trials necessary to support anticipated regulatory applications in its territory.

Seattle Genetics will receive from Merck $125 million as an upfront payment and is eligible to receive progress-dependent milestones of up to $65 million. Seattle Genetics will also receive $85 million in prepaid research and development payments to be applied to Merck’s global development funding obligations. In addition, Seattle Genetics would receive tiered royalties on sales of TUKYSA in Merck’s territory.

The financial impact of these collaborations is not included in Seattle Genetics’ 2020 guidance.

Seattle Genetics Conference Call Details

Seattle Genetics’ management will host a conference call to discuss these collaborations today at 6:00 a.m. Pacific Time (PT); 9:00 a.m. Eastern Time (ET). The event will be simultaneously webcast and available for replay from the Seattle Genetics website at www.seattlegenetics.com, under the Investors section. Investors may also participate in the conference call by calling 844-763-8274 (domestic) or +1 412-717-9224 (international). The conference ID is 10147850.

About Ladiratuzumab Vedotin

Ladiratuzumab vedotin is a novel investigational ADC targeted to LIV-1. Most metastatic breast cancers express LIV-1, which also has been detected in several other cancers, including lung, head and neck, esophageal and gastric. Ladiratuzumab vedotin utilizes Seattle Genetics’ proprietary ADC technology and consists of a LIV-1-targeted monoclonal antibody linked to a potent microtubule-disrupting agent, monomethyl auristatin E (MMAE) by a protease-cleavable linker. This novel ADC is designed to bind to LIV-1 on cancer cells and release the cell-killing agent into target cells upon internalization. Ladiratuzumab vedotin may also cause antitumor activity through other mechanisms, including activation of an immune response by induction of immunogenic cell death.

About TUKYSA (tucatinib)

TUKYSA is an oral, small molecule tyrosine kinase inhibitor (TKI) of HER2, a protein that contributes to cancer cell growth. TUKYSA in combination with trastuzumab and capecitabine was approved by the U.S. Food and Drug Administration (FDA) in April 2020 for adult patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients with brain metastases, who have received one or more prior anti-HER2-based regimens in the metastatic setting. In addition, TUKYSA received approval in Canada, Singapore, Australia and Switzerland under the Project Orbis initiative of the FDA Oncology Center of Excellence that provides a framework for concurrent submission and review of oncology products among international partners. A marketing application is under review in the European Union.

TUKYSA is being evaluated in several ongoing clinical trials and additional studies are planned. Current trials include the following:

  • HER2CLIMB-02: a randomized, double-blind phase 3 trial evaluating TUKYSA in combination with T-DM1 (trastuzumab emtansine; Kadcyla®) versus T-DM1 in first- and second-line metastatic HER2-positive breast cancer.
  • CompassHER2 RD: a randomized, double-blind phase 3 trial of TUKYSA in combination with T-DM1 versus T-DM1 in the adjuvant breast cancer setting for patients at high risk of relapse.
  • MOUNTAINEER: a pivotal phase 2 trial evaluating TUKYSA in combination with trastuzumab (Herceptin®) in metastatic HER2-positive colorectal cancer.
  • MOUNTAINEER-02: a randomized phase 2/3 trial evaluating TUKYSA in combination with trastuzumab, ramucirumab and paclitaxel versus ramucirumab and paclitaxel in second-line metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma (GEC).
  • Gastrointestinal cancers: a phase 1 trial evaluating TUKYSA in combination with trastuzumab and oxaliplatin-based chemotherapy in metastatic HER2-positive colorectal, gastric/ gastroesophageal junction and gallbladder cancers.

For additional information, visit www.clinicaltrials.gov.

About KEYTRUDA® (pembrolizumab) Injection, 100 mg

KEYTRUDA is an anti-PD-1 therapy that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. KEYTRUDA is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.

Merck has the industry’s largest immuno-oncology clinical research program. There are currently more than 1,200 trials studying KEYTRUDA across a wide variety of cancers and treatment settings. The KEYTRUDA clinical program seeks to understand the role of KEYTRUDA across cancers and the factors that may predict a patient’s likelihood of benefitting from treatment with KEYTRUDA, including exploring several different biomarkers.

Selected KEYTRUDA® (pembrolizumab) Indications

Melanoma

KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic melanoma.

KEYTRUDA is indicated for the adjuvant treatment of patients with melanoma with involvement of lymph node(s) following complete resection.

Non-Small Cell Lung Cancer

KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of patients with metastatic nonsquamous non-small cell lung cancer (NSCLC), with no EGFR or ALK genomic tumor aberrations.

KEYTRUDA, in combination with carboplatin and either paclitaxel or paclitaxel protein-bound, is indicated for the first-line treatment of patients with metastatic squamous NSCLC.

KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with NSCLC expressing PD-L1 [tumor proportion score (TPS) ≥1%] as determined by an FDA-approved test, with no EGFR or ALK genomic tumor aberrations, and is stage III where patients are not candidates for surgical resection or definitive chemoradiation, or metastatic.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with metastatic NSCLC whose tumors express PD-L1 (TPS ≥1%) as determined by an FDA-approved test, with disease progression on or after platinum-containing chemotherapy. Patients with EGFR or ALK genomic tumor aberrations should have disease progression on FDA-approved therapy for these aberrations prior to receiving KEYTRUDA.

Small Cell Lung Cancer

KEYTRUDA is indicated for the treatment of patients with metastatic small cell lung cancer (SCLC) with disease progression on or after platinum-based chemotherapy and at least 1 other prior line of therapy. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials.

Head and Neck Squamous Cell Cancer

KEYTRUDA, in combination with platinum and fluorouracil (FU), is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent head and neck squamous cell carcinoma (HNSCC).

KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC whose tumors express PD-L1 [combined positive score (CPS) ≥1] as determined by an FDA-approved test.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy.

Classical Hodgkin Lymphoma

KEYTRUDA is indicated for the treatment of adult and pediatric patients with refractory classical Hodgkin lymphoma (cHL), or who have relapsed after 3 or more prior lines of therapy. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

Primary Mediastinal Large B-Cell Lymphoma

KEYTRUDA is indicated for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL), or who have relapsed after 2 or more prior lines of therapy. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. KEYTRUDA is not recommended for treatment of patients with PMBCL who require urgent cytoreductive therapy.

Urothelial Carcinoma

KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma (mUC) who are not eligible for cisplatin-containing chemotherapy and whose tumors express PD-L1 [combined positive score (CPS) ≥10], as determined by an FDA-approved test, or in patients who are not eligible for any platinum-containing chemotherapy regardless of PD-L1 status. This indication is approved under accelerated approval based on tumor response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials.

KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma (mUC) who have disease progression during or following platinum-containing chemotherapy or within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy.

KEYTRUDA is indicated for the treatment of patients with Bacillus Calmette-Guerin (BCG)-unresponsive, high-risk, non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) with or without papillary tumors who are ineligible for or have elected not to undergo cystectomy.

Microsatellite Instability-High or Mismatch Repair Deficient Cancer

KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR)

  • solid tumors that have progressed following prior treatment and who have no satisfactory alternative treatment options, or
  • colorectal cancer that has progressed following treatment with fluoropyrimidine, oxaliplatin, and irinotecan.

This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials. The safety and effectiveness of KEYTRUDA in pediatric patients with MSI-H central nervous system cancers have not been established.

Microsatellite Instability-High or Mismatch Repair Deficient Colorectal Cancer

KEYTRUDA is indicated for the first-line treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC).

Gastric Cancer

KEYTRUDA is indicated for the treatment of patients with recurrent locally advanced or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test, with disease progression on or after two or more prior lines of therapy including fluoropyrimidine- and platinum-containing chemotherapy and if appropriate, HER2/neu-targeted therapy. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

Esophageal Cancer

KEYTRUDA is indicated for the treatment of patients with recurrent locally advanced or metastatic squamous cell carcinoma of the esophagus whose tumors express PD-L1 (CPS ≥10) as determined by an FDA-approved test, with disease progression after one or more prior lines of systemic therapy.

Cervical Cancer

KEYTRUDA is indicated for the treatment of patients with recurrent or metastatic cervical cancer with disease progression on or after chemotherapy whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

Hepatocellular Carcinoma

KEYTRUDA is indicated for the treatment of patients with hepatocellular carcinoma (HCC) who have been previously treated with sorafenib. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

Merkel Cell Carcinoma

KEYTRUDA is indicated for the treatment of adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC). This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

Renal Cell Carcinoma

KEYTRUDA, in combination with axitinib, is indicated for the first-line treatment of patients with advanced renal cell carcinoma (RCC).

Tumor Mutational Burden-High

KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic tumor mutational burden-high (TMB-H) [≥10 mutations/megabase (mut/Mb)] solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials. The safety and effectiveness of KEYTRUDA in pediatric patients with TMB-H central nervous system cancers have not been established.

Cutaneous Squamous Cell Carcinoma

KEYTRUDA is indicated for the treatment of patients with recurrent or metastatic cutaneous squamous cell carcinoma (cSCC) that is not curable by surgery or radiation.

Please see Prescribing Information for KEYTRUDA (pembrolizumab) at https://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_pi.pdf and Medication Guide for KEYTRUDA at https://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_mg.pdf

About Seattle Genetics

Seattle Genetics, Inc. is a global biotechnology company that discovers, develops and commercializes transformative cancer medicines to make a meaningful difference in people’s lives. ADCETRIS® (brentuximab vedotin) and PADCEV® (enfortumab vedotin-ejfv) use the company’s industry-leading antibody-drug conjugate (ADC) technology. ADCETRIS is approved in certain CD30-expressing lymphomas, and PADCEV is approved in certain metastatic urothelial cancers. TUKYSA® (tucatinib), a small molecule tyrosine kinase inhibitor, is approved in certain HER2-positive metastatic breast cancers. The company is headquartered in the Seattle, Washington area, with locations in California, Switzerland and the European Union. For more information on our robust pipeline, visit www.seattlegenetics.com and follow @SeattleGenetics on Twitter.

Merck’s Focus on Cancer

Our goal is to translate breakthrough science into innovative oncology medicines to help people with cancer worldwide. At Merck, the potential to bring new hope to people with cancer drives our purpose and supporting accessibility to our cancer medicines is our commitment. As part of our focus on cancer, Merck is committed to exploring the potential of immuno-oncology with one of the largest development programs in the industry across more than 30 tumor types. We also continue to strengthen our portfolio through strategic acquisitions and are prioritizing the development of several promising oncology candidates with the potential to improve the treatment of advanced cancers. For more information about our oncology clinical trials, visit www.merck.com/clinicaltrials.

About Merck

For more than 125 years, Merck, known as MSD outside of the United States and Canada, has been inventing for life, bringing forward medicines and vaccines for many of the world’s most challenging diseases in pursuit of our mission to save and improve lives. We demonstrate our commitment to patients and population health by increasing access to health care through far-reaching policies, programs and partnerships. Today, Merck continues to be at the forefront of research to prevent and treat diseases that threaten people and animals – including cancer, infectious diseases such as HIV and Ebola, and emerging animal diseases – as we aspire to be the premier research-intensive biopharmaceutical company in the world. For more information, visit www.merck.com and connect with us on Twitter, Facebook, Instagram, YouTube and LinkedIn.

SOURCE: Merck