Amgen announces top-line results of Vectibix® (panitumumab)

Amgen (NASDAQ:AMGN) today announced that the Phase 3 head-to-head ASPECCT (‘763) trial evaluating Vectibix® (panitumumab) versus Erbitux® (cetuximab) as a single agent for the treatment of chemorefractory metastatic colorectal cancer (mCRC) in patients with wild-type KRAS tumors (n=1,010) met its primary endpoint of non-inferiority for overall survival. The estimated overall survival hazard ratio (Vectibix/Erbitux) was 0.966 (95 percent CI: 0.839, 1.113) favoring the Vectibix arm.

Overall, the relative adverse event profiles were as anticipated for each of the anti-EGFR therapies studied, including known events such as rash, diarrhea and hypomagnesemia.

Colorectal cancer is the third most common cancer found in both men and women in the U.S., and is the second leading cause of cancer deaths.1, 2 Approximately 1.2 million cases of colorectal cancer are expected to occur globally.3

Detailed safety and efficacy data will be submitted for presentation at an upcoming medical meeting later this year.

ASPECCT (‘763) Trial Design

ASPECCT is a global, randomized, parallel assignment, open-label, Phase 3 non-inferiority trial designed to compare the effect of Vectibix versus Erbitux on overall survival for monotherapy treatment of chemorefractory mCRC in 1,010 patients with wild-type KRAS tumors (primary endpoint). Secondary endpoints included safety, patient reported outcomes, progression-free survival, time to response, time to treatment failure and duration of response.

Patients were randomized in a 1:1 ratio to receive 6 mg/kg of intravenous Vectibix every 14 days or 400 mg/m2 of an initial dose of intravenous Erbitux followed by 250 mg/m2 of intravenous Erbitux every seven days.

In Europe, the ASPECCT trial is a Specific Obligation for Vectibix as part of the European Medicine Agency’s (EMA) conditional marketing authorization.

About Vectibix

Vectibix is the first fully human anti-epidermal growth factor receptor (EGFR) antibody approved by the U.S. Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer (mCRC). Vectibix was approved in the U.S. in September 2006 as a single agent for the treatment of metastatic colorectal carcinoma with disease progression on or following fluoropyrimidine, oxaliplatin and irinotecan chemotherapy regimens. Approval is based on progression-free survival; no data demonstrate an improvement in disease-related symptoms or increased survival with Vectibix.

Important U.S. Product Information

Vectibix is indicated as a single agent for the treatment of EGFR-expressing, mCRC with disease progression on or following fluoropyrimidine-, oxaliplatin- and irinotecan-containing chemotherapy regimens. The effectiveness of Vectibix as a single agent for the treatment of EGFR-expressing mCRC is based on progression-free survival. Currently, no data demonstrate an improvement in disease-related symptoms or increased survival with Vectibix.

Vectibix is not indicated for the treatment of patients with KRAS mutation-positive mCRC or for whom KRAS mCRC status is unknown. Retrospective subset analyses of mCRC trials have not shown a treatment benefit for Vectibix in patients whose tumors had KRAS mutations in codon 12 or 13.

WARNING: DERMATOLOGIC TOXICITY and INFUSION REACTIONS

Dermatologic Toxicity: Dermatologic toxicities occurred in 89 percent of patients and were severe (NCI-CTC grade 3 or higher) in 12 percent of patients receiving Vectibix monotherapy. [See Dosage and Administration (2.1), Warnings and Precautions (5.1), and Adverse Reactions (6.1)].

Infusion Reactions: Severe infusion reactions occurred in approximately one percent of patients. Fatal infusion reactions occurred in postmarketing experience. [See Dosage and Administration (2.1), Warnings and Precautions (5.2), and Adverse Reactions (6.1, 6.3)].

The most common adverse reactions (≥ 20 percent) of Vectibix are skin rash with variable presentations, hypomagnesemia, paronychia, fatigue, abdominal pain, nausea, diarrhea, including diarrhea resulting in dehydration.

The most serious adverse reactions of Vectibix are pulmonary fibrosis, pulmonary embolism, severe dermatologic toxicity complicated by infectious sequelae and septic death, infusion reactions, abdominal pain, hypomagnesemia, nausea, vomiting, and constipation.

Important European Product Information

• Vectibix has been approved in the European Union for the treatment of patients with wild-type KRAS metastatic colorectal cancer (mCRC):
  – in first-line in combination with FOLFOX
  – in second-line in combination with FOLFIRI for patients who have received first-line fluoropyrimidine-based chemotherapy (excluding irinotecan)
  – as monotherapy after failure of fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens.
• Vectibix is contraindicated in patients with a history of severe or life-threatening hypersensitivity reactions to the product and in patients with interstitial pneumonitis or pulmonary fibrosis. Vectibix should not be administered in combination with oxaliplatin-containing chemotherapy to mCRC patients with mutant KRAS tumors or for whom KRAS tumor status is unknown.
• Adverse events of special importance associated with Vectibix and/or EGFR monoclonal antibody therapies include dermatologic-related reactions, pulmonary complications, electrolyte disturbances, infusion-related reactions (including rare reports with fatal outcome) and ocular toxicities. Acute renal failure has been observed in patients who develop severe diarrhea and dehydration. These events should be monitored carefully, see Summary of Product Characteristics for information on appropriate management of these adverse events.
• Vectibix should not be used in combination with IFL chemotherapy or in combination with bevacizumab containing chemotherapy. For patients with ECOG 2 performance status, assessment of benefit-risk is recommended prior to initiation of Vectibix in combination with chemotherapy for treatment of mCRC.

To see the full Vectibix Safety Information, visit www.vectibix.com.