Amgen has entered into a definitive agreement with GSK to reacquire all of its remaining rights to Prolia (denosumab), Xgeva (denosumab) and Vectibix (panitumumab) in 48 countries in Asia, South America, Europe, Australia and other regions throughout the world. The agreement involves key expansion markets for Amgen including Brazil, China, Colombia, Hong Kong, Israel, Singapore, South Korea, Taiwan and Thailand.

GSK has held select regional rights to Prolia and Xgeva since 2009 and to Vectibix since 2010 under license from Amgen. In 2014, GSK generated approximately $111 million in combined sales from these licenses. Amgen will make undisclosed milestone payments to GSK on signing and on the successful transition of the products back to Amgen. Amgen will book all product sales following this transition.

"This unique agreement with GSK allows Amgen to regain rights to three important growth products, and to directly serve more patients in key expansion markets," said Robert A. Bradway, chairman and chief executive officer of Amgen. "The agreement also allows Amgen to build additional commercial infrastructure in oncology and bone health, two strategically important therapeutic areas for Amgen with emerging late-stage pipeline assets."

Amgen will work closely with GSK to enable a seamless transition for customers and patients. GSK will continue to hold the license and sell and distribute the products for an interim transition period that will vary by country. The majority of markets are planned to be transitioned back to Amgen within a 12-month period.

Amgen anticipates this transaction to be accretive to adjusted earnings in 2017.

Prolia is the first approved therapy that specifically targets RANK Ligand, an essential regulator of bone-removing cells (osteoclasts).

Prolia is approved in the US for the treatment of postmenopausal women with osteoporosis at high risk for fracture, defined as a history of osteoporotic fracture, or multiple risk factors for fracture; or patients who have failed or are intolerant to other available osteoporosis therapy. Prolia is also approved for treatment to increase bone mass in men with osteoporosis at high risk for fracture, defined as a history of osteoporotic fracture, or multiple risk factors for fracture; or patients who have failed or are intolerant to other available osteoporosis therapy.

Prolia is also indicated as a treatment to increase bone mass in women at high risk for fracture receiving adjuvant aromatase inhibitor therapy for breast cancer and in men at high risk for fracture receiving androgen deprivation therapy for non-metastatic prostate cancer.

Prolia is administered as a single subcutaneous injection of 60 mg once every six months.

In a clinical trial (N = 7808) in women with postmenopausal osteoporosis, serious infections leading to hospitalization were reported more frequently in the Prolia group than in the placebo group. Serious skin infections, as well as infections of the abdomen, urinary tract and ear, were more frequent in patients treated with Prolia.

Xgeva was approved by the FDA in 2010 for the prevention of skeletal-related events (SREs) in patients with bone metastases from solid tumours (Xgeva is not indicated for the prevention of SREs in patients with multiple myeloma).

In clinical trials, Xgeva demonstrated a clinically meaningful improvement compared to zoledronic acid (the previous standard of care) in preventing SREs, which were defined as radiation to bone, pathologic fracture, surgery to the bone, and spinal cord compression. Xgeva is administered as a single subcutaneous injection of 120 mg once every 4 weeks.

In 2013, Xgeva was approved by the FDA as the first-and-only treatment for adults and skeletally mature adolescents with giant cell tumor of bone that is unresectable or where surgical resection is likely to result in severe morbidity. Xgeva is administered as a single subcutaneous injection of 120 mg once every 4 weeks with additional 120 mg doses administered on days 8 and 15 of the first month of therapy.

In 2014, Xgeva was approved by the FDA for the treatment of hypercalcemia of malignancy refractory to bisphosphonate therapy. Xgeva is administered as a single subcutaneous injection of 120 mg once every 4 weeks with additional 120 mg doses administered on days 8 and 15 of the first month of therapy.

The most common adverse reactions in patients receiving Xgeva with bone metastasis from solid tumours were fatigue/asthenia, hypophosphatemia, and nausea. The most common serious adverse reaction was dyspnea.

Vectibix is the first fully human anti-EGFR antibody approved by the US Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer (mCRC). Vectibix was approved in the US in September 2006 as a monotherapy for the treatment of patients with EGFR-expressing mCRC after disease progression after prior treatment with fluoropyrimidine-,  oxaliplatin-, and irinotecan-containing chemotherapy.

In May 2014, the FDA approved Vectibix for use in combination with FOLFOX, as first-line treatment in patients with wild-type KRAS (exon 2) mCRC. With this approval, Vectibix became the first-and-only biologic therapy indicated for use with FOLFOX, one of the most commonly used chemotherapy regimens, in the first-line treatment of mCRC for patients with wild-type KRAS mCRC.