Attractive Addition to Amgen's Leading Oncology Portfolio and Pipeline

Kyprolis(R) (car­filz­o­mib) for Injection Is at Early Stages of Launch in Multiple Myeloma; Showing Strong Physician Support

Acquisition Expected to Contribute to Growth and Value for Amgen Shareholders

Amgen to Host Analyst/Investor Call Monday at 8:30 a.m. EDT (5:30 a.m. PDT)

Thousand Oaks, CA and South San Francisco, CA (Press Release) - Amgen (NASDAQ: AMGN) and Onyx Pharma­ceu­ticals, Inc. (NASDAQ: ONXX) today announced that their Boards of Directors have unanimously approved a trans­­action under which Amgen will acquire all of the outstanding shares of Onyx for $125 per share in cash. The purchase price is $10.4 billion, or $9.7 billion net of esti­mated Onyx cash.

Onyx Pharma­ceu­ticals, Inc. is a global bio­pharma­ceu­tical com­pany engaged in the devel­op­ment and com­mer­cialization of inno­va­tive ther­a­pies for im­prov­ing the lives of people with cancer. Onyx has an im­por­tant and growing multiple myeloma franchise, with Kyprolis® (car­filz­o­mib) for Injection already approved in the United States (U.S.). In addi­tion, Onyx has three partnered on­col­ogy assets: Nexavar® (sorafenib) tablets (an Onyx and Bayer HealthCare Pharma­ceu­ticals, Inc. com­pound), Stivarga® (regorafenib) tablets (a Bayer com­pound), and palbociclib (a Pfizer, Inc. com­pound). Onyx also has multiple on­col­ogy com­pounds in various stages of clin­i­cal devel­op­ment.

Amgen intends to effect the trans­­action through a tender offer and ex­pec­ts to close at the beginning of the fourth quarter, subject to the satisfaction of customary closing con­di­tions, in­­clud­ing the receipt of regu­la­tory clearance.

"We believe that Amgen is strongly positioned to realize the full poten­tial of Onyx's portfolio and pipe­line for the benefit of physicians and patients," said Robert A. Bradway, chairman and chief exec­u­tive officer at Amgen. "Our acquisition follows a thorough due diligence process and is fully con­sis­tent with our strategy of ad­vanc­ing inno­va­tive medicines that address serious unmet medical needs. We ex­pec­t this acquisition will accelerate growth and en­hance value for Amgen share­holders.

"Amgen has a unique oppor­tu­ni­ty to add value to Kyprolis, a prod­uct which is at an early and promising stage of its launch," Bradway con­tinued.

Onyx holds global rights to Kyprolis, excluding Japan. Kyprolis has an orphan drug desig­na­tion in the U.S. with exclusivity until July 2019, and patents in the U.S. which extend until at least 2025.

Amgen will benefit from the global rights to Onyx's inno­va­tive on­col­ogy portfolio and pipe­line. Amgen intends to leverage its on­col­ogy capabilities and ex­peri­ence to sup­port Onyx's clin­i­cal devel­op­ment pro­grams and maximize Kyprolis' poten­tial in the U.S. and the rest of the world.

The acquisition of Onyx also adds to Amgen's robust late-stage pipe­line. This pipe­line in­cludes nine in­no­vative prod­ucts for which registration-enabling data are antic­i­pated by 2016. Four of these are inno­va­tive, first-in-class on­col­ogy. Onyx's pipe­line complements Amgen's growing on­col­ogy portfolio.

In addi­tion to accelerating Amgen's revenue growth, the acquisition of Onyx is ex­pec­ted to be accretive to Amgen's adjusted net income in 2015.

"After a careful and thorough evaluation process, our Board of Directors has determined that the all-cash trans­­action with Amgen maximizes value for our stockholders and expands the poten­tial of our commercial medicines and clin­i­cal pipe­line to reach more patients globally," said Dr. Tony Coles, chairman and chief exec­u­tive officer of Onyx.

Coles con­tinued, "We are pleased to have reached this agree­ment with Amgen, a com­pany that shares Onyx's vision for inno­va­tion on behalf of patients. This trans­­action is an im­por­tant affirmation of the mean­ing­ful value our employees have created, and we look forward to rewarding our stockholders with an im­medi­ate and attractive premium."

Bradway concluded, "Our two com­pa­nies share a strong cul­ture of inno­va­tion and a focus on patient needs. I look forward to bringing the talented people of Onyx and Amgen together as we con­tinue to fulfill our commitment to unlocking the poten­tial of biology for patients suffering from serious illnesses."

Benefits of the Transaction

Excellent Strategic Fit: Amgen's strategy is to ad­vance inno­va­tive medicines that address serious unmet medical needs.

• Amgen is a global leader in oncology. As a focused oncology company, Onyx's products and pipeline strengthen Amgen's leading position in this field.
• Onyx's oncology pipeline adds to Amgen's existing pipeline that addresses areas of serious unmet medical need. Amgen's current pipeline includes nine products for which registration-enabling data are anticipated by 2016.
• The acquisition of Onyx enables Amgen to continue building its position in international markets, capitalizing on its worldwide commercial, development and manufacturing capabilities. Onyx has global rights to Kyprolis (excluding Japan) and has clinical trials underway supporting an expected European Union (EU) filing in 2014.
• Amgen's track record in quality and reliability of supply and efficiency in manufacturing will bring an added source of value to the Onyx portfolio.
• The transaction is expected to deliver meaningful revenue growth and return on capital and to be accretive to adjusted net income in 2015. This will support Amgen's commitment to continue to meaningfully increase its dividend over time.

Positions Amgen to Address Growing Patient Needs in Multiple Myeloma

• Kyprolis is at an early stage of its launch, with global rights, excluding Japan, held by Onyx. It has an orphan drug designation in the U.S. with exclusivity until July 2019, and patents in the U.S. which extend until at least 2025. Amgen believes there is a significant opportunity to grow Kyprolis, including potential expansion into earlier lines of multiple myeloma treatment and into international markets.
  Ongoing studies to support and extend Kyprolis' position in multiple myeloma include:
  • The ASPIRE trial, which is investigating the addition of Kyprolis to Revlimid®(lenalidomide)(1) and dexamethasone in patients with relapsed multiple myeloma who have received one to three prior therapies. An interim analysis is expected to read out in 2014. ASPIRE is the confirmatory trial for full U.S. approval as well as a registration-enabling study for relapsed multiple myeloma in the U.S. and EU.
  • The FOCUS trial, which could support the EU filing for the indication of relapsed/refractory multiple myeloma, is also expected to read out in 2014.
  • The ENDEAVOR trial, underway to compare Kyprolis to Velcade® (bortezomib)(2) in patients with relapsed multiple myeloma who have received one to three prior therapies.
  • The CLARION trial, underway to compare Kyprolis to Velcade in patients with newly diagnosed multiple myeloma.
• Oprozomib, an inves­ti­ga­tional oral pro­te­a­some inhibitor, is in Phase 1b/2 trials and has the poten­tial to play an im­por­tant future role in the man­agement of multiple myeloma.
• Across the multiple myeloma plat­form, Amgen's ex­peri­ence in on­col­ogy can help guide Onyx's pipe­line to suc­cess­ful approval and reim­burse­ment.

(1) Revlimid® is a registered trademark of Celgene Corpo­ra­tion.
(2) Velcade® is a registered trademark of Millennium Pharma­ceu­ticals, Inc.

Provides Additional Sources of Revenue Growth and Profitability

• Nexavar® (sorafenib) tablets is Onyx and Bayer's oral kinase inhibitor, currently approved in the U.S. for unresectable hepatocellular carcinoma (HCC) and advanced renal cell carcinoma (RCC). It is being studied in locally advanced or metastatic HER2 negative breast cancer. Nexavar has also been submitted for U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) approval for the treatment of radioactive iodine-refractory differentiated thyroid cancer. Nexavar is co-developed by Onyx and Bayer except in Japan where Bayer manages all development. The companies co-promote Nexavar in the U.S. Outside of the U.S., Bayer has exclusive marketing rights, and Bayer and Onyx share profits globally, excluding Japan.
• Stivarga® (regorafenib) tablets is Bayer's oral multiple kinase inhibitor, currently approved in the U.S. for the treatment of patients with metastatic colorectal cancer (mCRC) who have been previously treated with fluoropyrimidine-, oxaliplatin- and irinotecan-based chemotherapy, an anti-VEGF therapy, and, if KRAS wild type, an anti-EGFR therapy. It is also indicated for the treatment of patients with locally advanced, unresectable or metastatic gastrointestinal stromal tumor (GIST) who have been previously treated with imatinib mesylate and sunitinib malate. Stivarga is a Bayer compound developed by Bayer and jointly promoted by Bayer and Onyx in the U.S. In 2011, Bayer entered into an agreement with Onyx, under which Onyx receives a 20 percent royalty on all global net sales of Stivarga in oncology.
• Palbociclib is Pfizer's investigational oral, small molecule cyclin-dependent kinase 4/6 inhibitor being developed by Pfizer in a Phase 3 trial for ER+, HER2-negative advanced breast cancer. Palbociclib has received Breakthrough Therapy designation by the FDA based on preliminary Phase 2 data showing improvement in median progression-free survival in combination therapy. Onyx will receive an eight percent royalty on future worldwide sales of palbociclib.

Financing and Approvals
Amgen will finance the acquisition with $8.1 billion in committed bank loans and the bal­ance with cash avail­able in the U.S. The loans have five year terms and carry an average interest charge of LIBOR plus 104 basis points. Amgen ex­pec­ts to retain its investment grade credit rating fol­low­ing this trans­­action and remains committed to meaningfully in­creas­ing the dividend over time. The trans­­action is subject to the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act and other customary closing con­di­tions.

Lazard is acting as lead advisor to Amgen; BofA Merrill Lynch is acting as co-advisor and is also lead arranger for the financing; and Sullivan & Cromwell LLP is serving as legal counsel. Centerview Partners, LLC is acting as financial advisor to Onyx and Goodwin Procter, LLP is serving as legal counsel.

Investor Conference Call / Webcast Information
Amgen will host a conference call and webcast at 8:30 a.m. EDT (5:30 a.m. PDT) on Monday, Aug. 26 to provide more in­for­ma­tion on this announcement. The webcast and accompanying slides can be accessed at www.amgen.com. A real-time and post-call webcast will be avail­able for 7 days fol­low­ing the call under the Investor section of www.amgen.com.

Conference Call Dial-in:
Domestic: 877-456-7504
International: 706-643-3140
Passcode: 40362332

Replay Dial-in:
Domestic: 855-859-2056
International: 404-537-3406
Passcode: 40362332

About Kyprolis® (car­filz­o­mib) for Injection
Kyprolis® (car­filz­o­mib) for Injection, a pro­te­a­some inhibitor, is approved for the treat­ment of patients with multiple myeloma who have received at least two prior ther­a­pies, in­­clud­ing bor­tez­o­mib and an im­muno­modu­la­tory agent, and have dem­onstrated disease pro­gres­sion on or within 60 days of completion of the last ther­apy. Approval is based on response rate. Currently, no data are avail­able for Kyprolis that dem­onstrate an im­prove­ment in pro­gres­sion-free survival or over­all survival.

Important Safety Information Regarding Kyprolis® (car­filz­o­mib) for Injection

On July 20, 2012, the FDA granted accelerated approval of Kyprolis® (car­filz­o­mib) for Injection for the treat­ment of patients with multiple myeloma who have received at least two prior ther­a­pies in­­clud­ing bor­tez­o­mib and an immuno­modu­la­tory agent (IMiD), and have dem­onstrated disease pro­gres­sion on or within 60 days of completion of the last ther­apy. Approval was based on response rate. Clinical benefit, such as im­prove­ment in survival or symp­toms, has not been verified.

Safety data have been eval­u­ated in 526 patients with re­lapsed and/or refractory multiple myeloma who received single-agent Kyprolis. There were 37 deaths in the Phase 2 studies, or 7% of patients. The most common causes of death, other than disease pro­gres­sion, were cardiac (5 patients), end-organ failure (4 patients), and in­fec­tion (4 patients). Important warnings and precautions in­clude cardiac arrest, congestive heart failure, myo­cardial ischemia; pul­mo­nary hyper­tension, pul­mo­nary com­pli­ca­tions, infusion reac­tions, tumor lysis syn­drome, thrombo­cyto­penia, hepatic toxicity and embryo-fetal toxicity.

Death due to cardiac arrest has occurred within a day of Kyprolis admin­istra­tion. Patients with New York Heart Association Class III and IV heart failure, myo­cardial infarction in the preceding 6 months, and con­duction ab­nor­mal­i­ties uncontrolled by medications were not eli­gible for the clin­i­cal trials. These patients may be at greater risk for cardiac com­pli­ca­tions.

Pulmonary arterial hyper­tension (PAH) was reported in 2% of patients treated with Kyprolis and was Grade 3 or greater in less than 1% of patients. Dyspnea was reported in 35% of patients enrolled in clin­i­cal trials. Grade 3 dyspnea occurred in 5%; no Grade 4 events, and 1 death (Grade 5) was reported.

Infusion reac­tions, char­ac­ter­ized by a spectrum of systemic symp­toms in­­clud­ing fever, chills, arthralgia, myalgia, facial flushing, facial edema, vomiting, weakness, shortness of breath, hypo­tension, syncope, chest tightness, or angina can occur im­medi­ately fol­low­ing or up to 24 hours after admin­istra­tion of Kyprolis. Admin­istra­tion of dexa­meth­a­sone prior to Kyprolis reduces the incidence and severity of reac­tions. Tumor lysis syn­drome (TLS) occurred fol­low­ing Kyprolis admin­istra­tion in < 1% of patients.

Patients with multiple myeloma and a high tumor burden should be con­sidered to be at greater risk for TLS.

Thrombocytopenia fol­low­ing Kyprolis admin­istra­tion resulted in a dose reduction in 1% of patients and dis­con­tinu­a­tion of treat­ment with Kyprolis in < 1% of patients.

Cases of hepatic failure, in­­clud­ing fatal cases, have been reported (< 1%). Kyprolis can cause elevations of serum transaminases and bilirubin.

There are no adequate and well-controlled studies in pregnant women using Kyprolis. Females of re­pro­ductive poten­tial should be advised to avoid becoming pregnant while being treated with Kyprolis.

The most common serious adverse reac­tions were pneu­monia, acute renal failure, pyrexia, and congestive heart failure. The most common adverse reac­tions (incidence of 30% or greater) observed in clin­i­cal trials of patients with multiple myeloma were fatigue, anemia, nausea, thrombo­cyto­penia, dyspnea, diarrhea, and pyrexia. Serious adverse reac­tions were reported in 45% of patients.

Full pre­scrib­ing in­for­ma­tion is avail­able at http://www.onyx.com.

About Nexavar® (sorafenib) Tablets
Nexavar is approved in the U.S. for the treat­ment of patients with unresectable hepato­cellular carcinoma and for the treat­ment of patients with ad­vanced renal cell carcinoma. Nexavar is thought to inhibit both the tumor cell and tumor vasculature. In in vitro studies, Nexavar has been shown to inhibit multiple kinases thought to be involved in both cell proliferation (growth) and angiogenesis (blood supply) - two im­por­tant processes that enable cancer growth. These kinases in­clude Raf kinase, VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-B, KIT, FLT-3 and RET.

Nexavar is cur­rently approved in more than 100 countries. Nexavar is also being eval­u­ated by Bayer and Onyx, inter­na­tional study groups, gov­ern­ment agencies and individual investigators in a range of cancers.

Important Safety Considerations For Nexavar® (sorafenib) Tablets

Nexavar in com­bi­na­tion with carboplatin and paclitaxel is con­tra­in­di­cated in patients with squamous cell lung cancer.

Cardiac ischemia and/or myo­cardial infarction may occur. Temporary or perma­nent dis­con­tinu­a­tion of Nexavar should be con­sidered in patients who develop cardiac ischemia and/or myo­cardial infarction.

An in­­creased risk of bleeding may occur fol­low­ing Nexavar admin­istra­tion. If bleeding necessitates medical intervention, con­sider perma­nent dis­con­tinu­a­tion of Nexavar.

Hypertension may occur early in the course of treat­ment. Monitor blood pressure weekly during the first 6 weeks and periodically there­after and treat, if required.

Hand-foot skin reac­tion and rash are common and man­agement may in­clude topical ther­a­pies for symp­to­matic relief. In cases of any severe or persistent adverse reac­tions, temporary treat­ment inter­rup­tion, dose modification, or perma­nent dis­con­tinu­a­tion of Nexavar should be con­sidered. Nexavar should be dis­con­tinued if Stevens-Johnson Syndrome or toxic epider­mal necrolysis are sus­pected as these may be life threatening.

Gastrointestinal perforation was an uncommon adverse reac­tion and has been reported in less than 1% of patients taking Nexavar. Discontinue Nexavar in the event of a gastro­in­tes­ti­nal perforation.

Patients taking concomitant warfarin should be monitored regularly for changes in prothrombin time (PT), Inter­na­tional Normalized Ratio (INR) or clin­i­cal bleeding episodes.

Temporary inter­rup­tion of Nexavar ther­apy is recommended in patients undergoing major surgical pro­cedures.

Nexavar in com­bi­na­tion with gemcitabine/cisplatin is not recommended in patients with squamous cell lung cancer. The safety and effectiveness of Nexavar has not been estab­lish­ed in patients with non-small cell lung cancer.

Nexavar can prolong the QT/QTc in­ter­val and in­­crease the risk for ventricular arrhythmias. Avoid use in patients with congenital long QT syn­drome and monitor patients with congestive heart failure, brady­ar­rhyth­mias, drugs known to prolong the QT in­ter­val, and electrolyte ab­nor­mal­i­ties.

Drug-induced hepatitis with Nexavar may result in hepatic failure and death. Liver function tests should be monitored regularly and in cases of in­­creased transaminases without alter­na­tive explanation Nexavar should be dis­con­tinued.

Nexavar may cause fetal harm when admin­istered to a pregnant woman. Women of childbearing poten­tial should be advised to avoid becoming pregnant while on Nexavar and female patients should also be advised against breastfeeding while receiving Nexavar.

Elevations in serum lipase and reductions in serum phosphate of unknown etiology have been asso­ci­ated with Nexavar.

Avoid concomitant use of strong CYP3A4 inducers, when possible, because inducers can de­crease the systemic exposure of Nexavar. Nexavar exposure de­creases when coadministered with oral neomycin. Effects of other antibiotics on Nexavar phar­ma­co­ki­netics have not been studied.

Most common adverse reac­tions reported for Nexavar-treated patients vs. placebo-treated patients in unresectable HCC, re­spec­tive­ly, were: diarrhea (55% vs. 25%), fatigue (46% vs. 45%), abdominal pain (31% vs. 26%), weight loss (30% vs. 10%), anorexia (29% vs. 18%), nausea (24% vs. 20%), and hand-foot skin reac­tion (21% vs. 3%). Grade 3/4 adverse reac­tions were 45% vs. 32%.

Most common adverse reac­tions reported for Nexavar-treated patients vs. placebo-treated patients in ad­vanced RCC, re­spec­tive­ly, were: diarrhea (43% vs. 13%), rash/desquamation (40% vs. 16%), fatigue (37% vs. 28%), hand-foot skin reac­tion (30% vs. 7%), alopecia (27% vs. 3%), and nausea (23% vs. 19%). Grade 3/4 adverse reac­tions were 38% vs. 28%.

For in­for­ma­tion about Nexavar in­­clud­ing U.S. Nexavar pre­scrib­ing in­for­ma­tion, visit www.nexavar-us.com or call 1.866.NEXAVAR (1.866.639.2827).

Nexavar® is a registered trademark of Bayer HealthCare Pharma­ceu­ticals, Inc.

About Stivarga® (regorafenib) Tablets
In the U.S., Stivarga is indicated for the treat­ment of patients with mCRC who have been pre­vi­ously treated with fluoropyrimidine-, oxaliplatin- and irinotecan-based chemo­ther­apy, an anti-VEGF ther­apy, and, if KRAS wild type, an anti-EGFR ther­apy. It is also indicated for the treat­ment of patients with locally ad­vanced, un­re­sectable or metastatic gastro­in­tes­ti­nal stromal tumor (GIST) who have been pre­vi­ously treated with imatinib mesylate and sunitinib malate.

Stivarga is an inhibitor of multiple kinases involved in normal cellular functions and in pathologic processes such as oncogenesis, tumor angiogenesis, and main­te­nance of the tumor microenvironment.

For full U.S. pre­scrib­ing in­for­ma­tion, in­­clud­ing BOXED WARNING, visit www.stivarga-us.com.

Important U.S. Safety Information for Stivarga® (regorafenib) Tablets

WARNING: HEPATOTOXICITY

Severe and sometimes fatal hepato­tox­ic­ity has been observed in clin­i­cal trials.

Monitor hepatic function prior to and during treat­ment.

Interrupt and then reduce or dis­con­tinue STIVARGA for hepato­tox­ic­ity as manifested by elevated liver function tests or hepato­cellular necrosis, depending upon severity and per­sis­tence.

Severe drug-induced liver injury with fatal out­come occurred in 0.3% of 1200 STIVARGA-treated patients across all clin­i­cal trials. In metastatic colorectal cancer (mCRC), fatal hepatic failure occurred in 1.6% of patients in the STIVARGA arm and in 0.4% of patients in the placebo arm; all the patients with hepatic failure had metastatic disease in the liver. In gastro­in­tes­ti­nal stromal tumor (GIST), fatal hepatic failure occurred in 0.8% of patients in the STIVARGA arm.

Obtain liver function tests (ALT, AST, and bilirubin) before initiation of STIVARGA and monitor at least every 2 weeks during the first 2 months of treat­ment. Thereafter, monitor monthly or more frequently as clin­i­cally indicated. Monitor liver function tests weekly in patients experiencing elevated liver function tests until im­prove­ment to less than 3 times the upper limit of normal (ULN) or base­line values. Temporarily hold and then reduce or perma­nently dis­con­tinue STIVARGA, depending on the severity and persistence of hepato­tox­ic­ity as manifested by elevated liver function tests or hepato­cellular necrosis.

STIVARGA caused an in­­creased incidence of hemorrhage. The over­all incidence (Grades 1-5) was 21% and 11% with STIVARGA vs 8% and 3% with placebo in mCRC and GIST patients, re­spec­tive­ly. Fatal hemor­rhage occurred in 4 of 632 (0.6%) STIVARGA-treated patients and involved the res­pira­tory, gastro­in­testi­nal, or genitourinary tracts. Permanently dis­con­tinue STIVARGA in patients with severe or life-threatening hemorrhage and monitor INR levels more frequently in patients receiving warfarin.

STIVARGA caused an in­­creased incidence of hand-foot skin reac­tion (HFSR) (also known as palmar-plantar erythrodysesthesia [PPE]) and severe rash, frequently requiring dose modification. The over­all incidence was 45% and 67% with STIVARGA vs 7% and 12% with placebo in mCRC and GIST patients, re­spec­tive­ly. Incidence of Grade 3 HFSR (17% vs 0% in mCRC and 22% vs 0% in GIST), Grade 3 rash (6% vs < 1% in mCRC and 7% vs 0% in GIST), serious adverse reac­tions of erythema multiforme (0.2% vs 0% in mCRC), and Stevens-Johnson syn­drome (0.2% vs 0% in mCRC) was higher in STIVARGA-treated patients. Toxic epider­mal necrolysis occurred in 0.17% of 1200 STIVARGA-treated patients across all clin­i­cal trials. Withhold STIVARGA, reduce the dose, or perma­nently dis­con­tinue depending on the severity and persistence of dermatologic toxicity.

STIVARGA caused an in­­creased incidence of hyper­tension (30% vs 8% in mCRC and 59% vs 27% in GIST with STIVARGA vs placebo, re­spec­tive­ly). Hypertensive crisis occurred in 0.25% of 1200 STIVARGA-treated patients across all clin­i­cal trials. Do not ini­ti­ate STIVARGA until blood pressure is adequately controlled. Monitor blood pressure weekly for the first 6 weeks of treat­ment and then every cycle, or more frequently, as clin­i­cally indicated. Temporarily or perma­nently withhold STIVARGA for severe or uncontrolled hyper­tension.

STIVARGA in­­creased the incidence of myo­cardial ischemia and infarction (1.2% with STIVARGA vs 0.4% with placebo). Withhold STIVARGA in patients who develop new or acute cardiac ischemia or infarction, and resume only after resolution of acute cardiac ischemic events if the poten­tial benefits outweigh the risks of further cardiac ischemia.

Reversible Posterior Leukoencephalopathy Syndrome (RPLS) occurred in 1 of 1200 STIVARGA-treated patients across all clin­i­cal trials. Confirm the diag­nosis of RPLS with MRI and dis­con­tinue STIVARGA in patients who develop RPLS.

Gastrointestinal perforation or fistula occurred in 0.6% of 1200 patients treated with STIVARGA across clin­i­cal trials. In GIST, 2.1% (4/188) of STIVARGA-treated patients developed gastro­in­tes­ti­nal fistula or perforation: of these, 2 cases of gastro­in­tes­ti­nal perforation were fatal. Permanently dis­con­tinue STIVARGA in patients who develop gastro­in­tes­ti­nal perforation or fistula.

Treatment with STIVARGA should be stopped at least 2 weeks prior to scheduled surgery. Resuming treat­ment after surgery should be based on clin­i­cal judgment of adequate wound heal­ing. STIVARGA should be dis­con­tinued in patients with wound dehiscence.

STIVARGA can cause fetal harm when admin­istered to a pregnant woman. Use effective con­tra­cep­tion during treat­ment and up to 2 months after completion of ther­apy. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the poten­tial hazard to the fetus.

Because many drugs are excreted in human milk and because of the poten­tial for serious adverse reac­tions in nursing infants from STIVARGA, a de­ci­sion should be made whether to dis­con­tinue nursing or dis­con­tinue the drug, taking into account the importance of the drug to the mother.

The most frequently observed adverse drug reac­tions (≥30%) in STIVARGA-treated patients vs placebo-treated patients in mCRC, re­spec­tive­ly, were: asthenia/​fatigue (64% vs 46%), de­creased appetite and food intake (47% vs 28%), HFSR/PPE (45% vs 7%), diarrhea (43% vs 17%), mucositis (33% vs 5%), weight loss (32% vs 10%), in­fec­tion (31% vs 17%), hyper­tension (30% vs 8%), and dysphonia (30% vs 6%).

The most frequently observed adverse drug reac­tions (≥30%) in STIVARGA-treated patients vs placebo-treated patients in GIST, re­spec­tive­ly, were: HFSR/PPE (67% vs 15%), hyper­tension (59% vs 27%), asthenia/fatigue (52% vs 39%), diarrhea (47% vs 9%), mucositis (40% vs 8%), dysphonia (39% vs 9%), in­fec­tion (32% vs 5%), de­creased appetite and food intake (31% vs 21%), and rash (30% vs 3%).

STIVARGA® is a trademark of Bayer®. Bayer® and the Bayer Cross® are registered Bayer.

About Amgen
Amgen is committed to unlocking the poten­tial of biology for patients suffering from serious illnesses by discovering, devel­op­ing, manu­fac­tur­ing and delivering inno­va­tive human thera­peutics. This ap­proach begins by using tools like ad­vanced human genetics to unravel the complexities of disease and under­stand the fundamentals of human biology.

Amgen focuses on areas of high unmet medical need and leverages its biologics manu­fac­tur­ing expertise to strive for solu­tions that im­prove health out­comes and dramatically im­prove people's lives. A bio­technology pioneer since 1980, Amgen has grown to be the world's largest independent bio­technology com­pany, has reached millions of patients around the world and is devel­op­ing a pipe­line of medicines with break­away poten­tial.

For more in­for­ma­tion, visit www.amgen.com and follow us on www.twitter.com/amgen.

About Onyx
Based in South San Francisco, California, Onyx Pharma­ceu­ticals, Inc. is a global bio­pharma­ceu­tical com­pany engaged in the devel­op­ment and com­mer­cial­iza­tion of inno­va­tive ther­a­pies for im­prov­ing the lives of people with cancer. The com­pany is focused on devel­op­ing novel medicines that target key molecular path­ways. For more in­for­ma­tion about Onyx, visit the com­pany's website at www.onyx.com. Onyx Phar­ma­ceu­ti­cals is on Twitter. Sign up to follow our Twitter feed @OnyxPharm at http://twitter.com/OnyxPharm.

Amgen Forward-Looking Statements
This news release con­tains forward-looking state­ments that are based on Amgen's current ex­pec­ta­tions and beliefs and are subject to a number of risks, un­cer­tain­ties and assump­tions that could cause actual results to differ ma­teri­ally from those described. All state­ments, other than state­ments of historical fact, are state­ments that could be deemed forward-looking state­ments, in­­clud­ing state­ments about the planned completion of the tender offer and the merger, esti­mates of revenues, operating margins, capital ex­pen­di­tures, cash, other financial metrics, ex­pec­ted legal, arbitration, political, regu­la­tory or clin­i­cal results or practices, customer and prescriber patterns or practices, reim­burse­ment activities and out­comes and other such esti­mates and results. Forward-looking state­ments involve sig­nif­i­cant risks and un­cer­tain­ties, in­­clud­ing those discussed below and more fully described in the Securities and Exchange Com­mis­sion (SEC) reports filed by Amgen, in­­clud­ing Amgen's most recent annual report on Form 10-K and any sub­se­quent periodic reports on Form 10-Q and Form 8-K. Please refer to Amgen's most recent Forms 10-K, 10-Q and 8-K for addi­tional in­for­ma­tion on the un­cer­tain­ties and risk factors related to Amgen's business. Unless other­wise noted, Amgen is providing this in­for­ma­tion as of August 25, 2013, and expressly disclaims any duty to update in­for­ma­tion con­tained in this news release.

No forward-looking state­ment can be guar­an­teed and actual results may differ ma­teri­ally from those Amgen projects. Risks and un­cer­tain­ties in­clude whether the proposed trans­­action described in this press release can be com­pleted in a timely manner, and whether the antic­i­pated benefits of the proposed trans­­action can be achieved. Discovery or identi­fi­ca­tion of new prod­uct can­di­dates or devel­op­ment of new indi­ca­tions for existing prod­ucts cannot be guar­an­teed and movement from concept to prod­uct is uncertain; consequently, there can be no guar­an­tee that any particular prod­uct can­di­date or devel­op­ment of a new indi­ca­tion for an existing prod­uct will be suc­cess­ful and become a commercial prod­uct. Further, pre­clin­i­cal results do not guar­an­tee safe and effective per­for­mance of prod­uct can­di­dates in humans. The complexity of the human body cannot be perfectly, or sometimes, even adequately modeled by computer or cell cul­ture systems or animal models. The length of time that it takes for Amgen to com­plete clin­i­cal trials and obtain regu­la­tory approval for prod­uct market­ing has in the past varied and Amgen ex­pec­ts similar variability in the future. Amgen develops prod­uct can­di­dates internally and through licensing col­lab­o­rations, part­ner­ships, joint ventures and acquisitions. Product can­di­dates that are derived from rela­tion­ships or acquisitions may be subject to disputes be­tween the parties or may prove to be not as effective or as safe as Amgen may have believed at the time of entering into such rela­tion­ship. Also, Amgen or others could identify safety, side effects or manu­fac­tur­ing problems with Amgen's prod­ucts after they are on the market. Amgen's business may be impacted by gov­ern­ment in­ves­ti­ga­tions, litigation and prod­uct liability claims. If Amgen fails to meet the compliance obli­ga­tions in the corporate integrity agree­ment be­tween Amgen and the U.S. gov­ern­ment, it could become subject to sig­nif­i­cant sanctions. Amgen depends on third parties for a sig­nif­i­cant portion of its manu­fac­tur­ing capacity for the supply of certain of its current and future prod­ucts and limits on supply may constrain sales of certain of its current prod­ucts and prod­uct can­di­date devel­op­ment.

In addi­tion, sales of Amgen's prod­ucts are affected by the reim­burse­ment policies imposed by third-party payers, in­­clud­ing gov­ern­ments, private insurance plans and man­aged care providers and may be affected by regu­la­tory, clin­i­cal and guideline devel­op­ments and domestic and inter­na­tional trends to­ward man­aged care and health­care cost con­tainment as well as U.S. legislation affecting pharma­ceu­tical pricing and reim­burse­ment. Government and others' reg­u­la­tions and reim­burse­ment policies may affect the de­vel­op­ment, usage and pricing of Amgen's prod­ucts. In addi­tion, Amgen competes with other com­pa­nies with respect to some of its marketed prod­ucts as well as for the discovery and devel­op­ment of new prod­ucts. Amgen believes that some of its newer prod­ucts, prod­uct can­di­dates or new indi­ca­tions for existing prod­ucts, may face com­pe­ti­tion when and as they are approved and marketed. Amgen's prod­ucts may compete against prod­ucts that have lower prices, estab­lish­ed reim­burse­ment, superior per­for­mance, are easier to admin­ister, or that are other­wise competitive with its prod­ucts. In addi­tion, while Amgen routinely obtains patents for its prod­ucts and tech­nology, the protection offered by its patents and patent appli­ca­tions may be chal­lenged, invalidated or circumvented by its com­pet­i­tors and there can be no guar­an­tee of Amgen's ability to obtain or main­tain patent protection for its prod­ucts or prod­uct can­di­dates. Amgen cannot guar­an­tee that it will be able to produce commercially suc­cess­ful prod­ucts or main­tain the commercial success of its existing prod­ucts. Amgen's stock price may be affected by actual or perceived market oppor­tu­ni­ty, competitive position, and success or failure of its prod­ucts or prod­uct can­di­dates. Further, the discovery of sig­nif­i­cant problems with a prod­uct similar to one of Amgen's prod­ucts that implicate an entire class of prod­ucts could have a ma­teri­al adverse effect on sales of the affected prod­ucts and on Amgen's business and results of operations.

The scientific in­for­ma­tion discussed in this news release related to prod­uct can­di­dates is pre­lim­i­nary and investigative. Such prod­uct can­di­dates are not approved by the U.S. Food and Drug Admin­istra­tion (FDA), and no conclusions can or should be drawn re­gard­ing the safety or effectiveness of the prod­uct can­di­dates. Only the FDA can determine whether the prod­uct can­di­dates are safe and effective for the use(s) being in­ves­ti­gated. Further, the scientific in­for­ma­tion discussed in this news release relating to new indi­ca­tions for prod­ucts is pre­lim­i­nary and investigative and is not part of the labeling approved by the U.S. Food and Drug Admin­istra­tion (FDA) for the prod­ucts. The prod­ucts are not approved for the inves­ti­ga­tional use(s) dis­cussed in this news release, and no conclusions can or should be drawn re­gard­ing the safety or effective­ness of the prod­ucts for these uses. Only the FDA can determine whether the prod­ucts are safe and effective for these uses. Healthcare professionals should refer to and rely upon the FDA-approved labeling for the prod­ucts, and not the in­for­ma­tion discussed in this news release.

Onyx Forward-Looking Statements
This news release con­tains "forward-looking state­ments" of Onyx within the meaning of the federal securities laws. These forward-looking state­ments in­clude, without limitation, state­ments re­gard­ing the ex­pec­ted timing of the completion of the trans­­action, Amgen's operation of the Onyx business fol­low­ing completion of the trans­­action, and state­ments re­gard­ing the future operation, the antic­i­pated growth of our business, global expansion and in­­creases to our inter­na­tional capabilities, our launch of Kyprolis in the United States, our investments in Phase 3 clin­i­cal trials, con­tri­bu­tions from our kinase inhibitor business and future cost of goods sold with respect to Kyprolis. These state­ments are subject to risks and un­cer­tain­ties that could cause actual results and events to differ ma­teri­ally from those antic­i­pated, in­­clud­ing, but not limited to, risks and un­cer­tain­ties related to: un­cer­tain­ties as to the timing of the trans­­action; un­cer­tain­ties as to the per­cent­age of Onyx stockholders tendering their shares in the offer; the possibility that competing offers will be made; the possibility that various closing con­di­tions for the trans­­action may not be satisfied or waived, in­­clud­ing that a gov­ern­mental entity may prohibit, delay or refuse to grant approval for the consummation of the trans­­action; the effects of disruption caused by the trans­­action making it more dif­fi­cult to main­tain rela­tion­­ships with employees, col­lab­o­rators, vendors and other business partners; the risk that stockholder litigation in connection with the trans­­action may result in sig­nif­i­cant costs of defense, indemnification and liability; Nexavar® (sorafenib) tablets, Kyprolis® (car­filz­o­mib) for Injection and Stivarga® (regorafenib) tablets being the only approved prod­ucts from which we may obtain revenue; com­pe­ti­tion; failures or delays in our clin­i­cal trials or the regu­la­tory process; dependence on our col­lab­o­rative rela­tion­­ship with Bayer; supply of Nexavar, Stivarga or Kyprolis; market acceptance and the rate of adoption of Nexavar, Stivarga and Kyprolis; pharma­ceu­tical pricing and reim­burse­ment pressures; serious adverse side effects, if they are asso­ci­ated with Nexavar, Stivarga or Kyprolis; gov­ern­ment reg­u­la­tion; possible failure to realize the antic­i­pated benefits of business acquisitions or strategic investments; protection of our intellectual property; and prod­uct liability risks; and other risks and un­cer­tain­ties discussed in Onyx's filings with the Securities and Exchange Com­mis­sion (the "Commission"), in­­clud­ing the "Risk Factors" sections of Onyx's most recent annual report on Form 10-K and sub­se­quent quarterly reports on Form 10-Q, as well as the tender offer documents to be filed by Arena Acquisition Corpo­ra­tion, a wholly owned sub­sid­i­ary of Amgen, and the Solicitation/Recommendation Statement to be filed by Onyx. Onyx under­takes no obli­ga­tion to update any forward-looking state­ments as a result of new in­for­ma­tion, future devel­op­ments or other­wise, except as expressly required by law.

Additional Information
The tender offer described in this communication (the "Offer") has not yet commenced, and this com­muni­ca­tion is neither an offer to purchase nor a solicitation of an offer to sell any shares of the common stock of Onyx Pharma­ceu­ticals, Inc. or any other securities. On the commencement date of the Offer, a tender offer state­ment on Schedule TO, in­­clud­ing an offer to purchase, a letter of transmittal and related documents, will be filed with the United States Securities and Exchange Com­mis­sion (the "SEC") by Amgen and a Solicitation/Recommendation Statement on Schedule 14D-9 will be filed with the SEC by Onyx. The offer to purchase shares of Onyx common stock will only be made pursuant to the offer to purchase, the letter of transmittal and related documents filed as a part of the Schedule TO. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ BOTH THE TENDER OFFER STATEMENT AND THE SOLICI­TA­TION/​RECOMMENDATION STATEMENT REGARDING THE OFFER, AS THEY MAY BE AMENDED FROM TIME TO TIME, WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. The tender offer state­ment will be filed with the SEC by Amgen and Arena Acquisition Company, a wholly owned sub­sid­i­ary of Amgen, and the solicitation/recommendation state­ment will be filed with the SEC by Onyx. Investors and security holders may obtain a free copy of these state­ments (when avail­able) and other documents filed with the SEC at the website main­tained by the SEC at www.sec.gov or by directing such requests to the Information Agent for the tender offer which will be named in the tender offer state­ment.

Source: Onyx Pharma­ceu­ticals.