Amgen announced results from new retrospective analyses of key studies

OREANDA-NEWS. Amgen (NASDAQ:AMGN) today announced results from new retrospective analyses of key studies with Vectibix^® (panitumumab) in metastatic colorectal cancer (mCRC) patients. The retrospective analysis of the PEAK study in mCRC patients with RAS wild-type primary tumors of left-sided origin showed that patients receiving Vectibix plus FOLFOX6 as first-line treatment achieved 43.4 months median overall survival (OS), an increase of 11.4 months when compared to FOLFOX6 plus bevacizumab. Additionally, for this patient population, the retrospective analysis of the PRIME study showed Vectibix plus FOLFOX4 increased OS by 6.7 months when compared to FOLFOX4 alone. These data were presented today at the European Society for Medical Oncology (ESMO) 2016 Congress in Copenhagen (Abstract #89P).

The PEAK and PRIME retrospective analyses, respectively, also showed that mCRC patients with RAS wild-type tumors of left-sided origin receiving Vectibix plus FOLFOX chemotherapy achieved median progression-free survival (PFS) of 14.6 months, an increase of 3.1 months when compared to FOLFOX plus bevacizumab, and 12.9 months, an increase of 3.7 months when compared to FOLFOX chemotherapy alone.

The retrospective analyses found that approximately 80 percent of tumors originate in the left side of the colon. Additionally, tumors originating in the right side of the colon are currently associated with a poorer prognosis than tumors originating in the left side of the colon. In patients with RAS wild-type mCRC with tumors originating on the right side, a subgroup of patients responded to Vectibix and chemotherapy, achieving numerically higher response rates over chemotherapy with or without bevacizumab. However, no final conclusions can be made regarding the ability to differentiate treatment regimens for patients with right-sided tumors. The safety profile of the use of Vectibix in combination with FOLFOX-based chemotherapy in mCRC has been previously reported (see summary of EU product safety information below). The aggregate safety data is unchanged by this retrospective analysis of outcomes based on CRC tumor site of origin.  

"Data from these retrospective analyses are helping Amgen make important connections between tumor biology and treatment outcomes," said Sean E. Harper, M.D., executive vice president of Research and Development at Amgen. "Tumor sidedness is a surrogate for differences in tumor biology and mutation load, potentially providing physicians with another means to help inform the treatment decisions for patients with metastatic colorectal cancer."

About the PRIME Study
PRIME was a randomized Phase 3 open-label study of first-line Vectibix and FOLFOX4 combination therapy versus FOLFOX4 monotherapy in 1,183 adults with untreated mCRC who had an Eastern Cooperative Oncology Group (ECOG) performance status of 0–2. The primary endpoints were PFS and OS.

Of the 1,183 patients enrolled in PRIME, 505 had RAS wild-type mCRC, of whom 456 were included in the quality of life analysis (Vectibix and FOLFOX4, n=232; FOLFOX4, n=224). The meta-analysis included PRIME data from 440 patients with RAS wild-type mCRC who were evaluable for OS and early tumor shrinkage (ETS).

About the PEAK Study
PEAK was a randomized Phase 2 open-label study of first-line Vectibix and FOLFOX6 versus bevacizumab and FOLFOX6 in 285 RAS wild-type mCRC patients. The primary endpoint was PFS. The meta-analysis included PEAK data from 154 patients with RAS wild-type mCRC who were evaluable for OS and ETS.

About the '181 Study
The '181 study was a randomized Phase 3 open-label study comparing Vectibix and FOLFIRI versus FOLFIRI alone as second-line treatments in 1,186 wild-typeKRAS (exon 2) mCRC patients who progressed on one prior fluoropyrimidine-based mCRC therapy. The co-primary endpoints were PFS and OS.

About Vectibix^® (panitumumab) in Europe
Vectibix is a fully human anti-epidermal growth factor receptor (EGFR) antibody approved by the European Commission (EC) for the treatment of mCRC. The safety and efficacy of Vectibix have not been studied in patients with renal or hepatic impairment.³ Vectibix was approved by the EC in December 2007 as a monotherapy for the treatment of patients with EGFR-expressing mCRC with non-mutated (wild-type) KRAS genes after failure of standard chemotherapy regimens.

In April 2015, the EC approved a new use of Vectibix as first-line treatment in combination with FOLFIRI for the treatment of adult patients with RAS wild-type mCRC. In November 2011, the EC expanded the marketing authorization to include indications for the treatment of patients with KRAS wild-type mCRC in first-line in combination with FOLFOX and in second-line in combination with FOLFIRI in patients who have received first-line fluoropyrimidine-based chemotherapy (excluding irinotecan).

Globally, over 240,000 patients have been treated with Vectibix and more than 6,000 patients have participated in Amgen-sponsored panitumumab clinical trials.

EU Product Safety Information

Summary of safety profile
Based on an analysis of all mCRC clinical trial patients receiving Vectibix monotherapy and in combination with chemotherapy (n = 2,588), the most commonly reported adverse reactions are skin reactions occurring in 93% of patients. These reactions are related to the pharmacologic effects of Vectibix, and the majority are mild to moderate in nature with 25% severe (grade 3 NCI-CTC) and < 1% life threatening (grade 4 NCI-CTC). For clinical management of skin reactions, including dose modification recommendations, see section 4.4. Very commonly reported adverse reactions occurring in ≥ 20% of patients were gastrointestinal disorders [diarrhoea (50%), nausea (41%), vomiting (27%), constipation (23%) and abdominal pain (23%)]; general disorders [fatigue (37%), pyrexia (20%)]; metabolism and nutrition disorders [anorexia (27%)]; infections and infestations [paronychia (20%)]; and skin and subcutaneous disorders [rash (45%), dermatitis acneiform (39%), pruritus (35%), erythema (30%) and dry skin (22%)].

Special warnings and precautions for use
Dermatologic reactions and soft tissue toxicity
Dermatologic related reactions, a pharmacologic effect observed with epidermal growth factor receptor (EGFR) inhibitors, are experienced with nearly all patients (approximately 90%) treated with Vectibix. Severe (NCI-CTC grade 3) skin reactions were reported in 34% and life-threatening (NCICTC grade 4) skin reactions in < 1% of patients who received Vectibix in combination with chemotherapy (n = 1,536) (see section 4.8). If a patient develops dermatologic reactions that are grade 3 (CTCAE v 4.0) or higher, or that are considered intolerable, the following dose modification is recommended:

 In clinical studies, subsequent to the development of severe dermatologic reactions (including stomatitis), infectious complications including sepsis and necrotising fasciitis, in rare cases leading to death, and local abscesses requiring incisions and drainage were reported. Patients who have severe dermatologic reactions or soft tissue toxicity or who develop worsening reactions whilst receiving Vectibix should be monitored for the development of inflammatory or infectious sequelae (including cellulitis and necrotising fasciitis), and appropriate treatment promptly initiated. Life threatening and fatal infectious complications including necrotising fasciitis and sepsis have been observed in patients treated with Vectibix. Rare cases of Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported in patients treated with Vectibix in the post-marketing setting. Withhold or discontinue Vectibix in the event of dermatologic or soft tissue toxicity associated with severe or life threatening inflammatory or infectious complications.

Treatment of dermatologic reactions should be based on severity and may include a moisturiser, sun screen (SPF > 15 UVA and UVB), and topical steroid cream (not stronger than 1% hydrocortisone) applied to affected areas, and/or oral antibiotics. It is also recommended that patients experiencing rash/dermatological toxicities wear sunscreen and hats and limit sun exposure as sunlight can exacerbate any skin reactions that may occur.

Proactive skin treatment including skin moisturiser, sun screen (SPF > 15 UVA and UVB), topical steroid cream (not stronger than 1% hydrocortisone) and an oral antibiotic (e.g. doxycycline) may be useful in the management of dermatologic reactions. Patients may be advised to apply moisturiser and sunscreen to face, hands, feet, neck, back and chest every morning during treatment, and to apply the topical steroid to face, hands, feet, neck, back and chest every night during treatment.

Pulmonary complications
Patients with a history of, or evidence of, interstitial pneumonitis or pulmonary fibrosis were excluded from clinical studies. Cases of interstitial lung disease (ILD), both fatal and non-fatal, have been reported, mainly from the Japanese population. In the event of acute onset or worsening pulmonary symptoms, Vectibix treatment should be interrupted and a prompt investigation of these symptoms should occur. If ILD is diagnosed, Vectibix should be permanently discontinued and the patient should be treated appropriately. In patients with a history of interstitial pneumonitis or pulmonary fibrosis, the benefits of therapy with panitumumab versus the risk of pulmonary complications must be carefully considered.

Electrolyte disturbances
Progressively decreasing serum magnesium levels leading to severe (grade 4) hypomagnesaemia have been observed in some patients. Patients should be periodically monitored for hypomagnesaemia and accompanying hypocalcaemia prior to initiating Vectibix treatment, and periodically thereafter for up 5 to 8 weeks after the completion of treatment. Magnesium repletion is recommended, as appropriate.

Other electrolyte disturbances, including hypokalaemia, have also been observed. Monitoring as above and repletion as appropriate of these electrolytes is also recommended.

Infusion related reactions
Across monotherapy and combination mCRC clinical studies (n = 2,588), infusion-related reactions (occurring within 24 hours of an infusion) were reported in approximately 4% of Vectibix-treated patients, of which < 1% were severe (NCI-CTC grade 3 and grade 4).

In the post-marketing setting, serious infusion-related reactions have been reported, including rare post-marketing reports with a fatal outcome. If a severe or life-threatening reaction occurs during an infusion or at any time post-infusion [e.g. presence of bronchospasm, angioedema, hypotension, need for parenteral treatment, or anaphylaxis], Vectibix should be permanently discontinued.

In patients experiencing a mild or moderate (CTCAE v 4.0 grades 1 and 2) infusion-related reaction the infusion rate should be reduced for the duration of that infusion. It is recommended to maintain this lower infusion rate in all subsequent infusions.

Hypersensitivity reactions occurring more than 24 hours after infusion have been reported including a fatal case of angioedema that occurred more than 24 hours after the infusion. Patients should be informed of the possibility of a late onset reaction and instructed to contact their physician if symptoms of a hypersensitivity reaction occur.

Acute renal failure
Acute renal failure has been observed in patients who develop severe diarrhoea and dehydration. Patients who experience severe diarrhoea should be instructed to consult a healthcare professional urgently.

Vectibix in combination with irinotecan, bolus 5-fluorouracil, and leucovorin (IFL) chemotherapy
Patients receiving Vectibix in combination with the IFL regimen [bolus 5-fluorouracil (500 mg/m2), leucovorin (20 mg/m2) and irinotecan (125 mg/m2)] experienced a high incidence of severe diarrhoea. Therefore administration of Vectibix in combination with IFL should be avoided.

Vectibix in combination with bevacizumab and chemotherapy regimens
A randomised, open-label, multicentre study of 1,053 patients evaluated the efficacy of bevacizumab and oxaliplatin- or irinotecan-containing chemotherapeutic regimens with and without Vectibix in the first-line treatment of metastatic colorectal cancer. Shortened progression free survival time and increased deaths were observed in the patients receiving Vectibix in combination with bevacizumab and chemotherapy. A greater frequency of pulmonary embolism, infections (predominantly of dermatologic origin), diarrhoea, electrolyte imbalances, nausea, vomiting and dehydration was also observed in the treatment arms using Vectibix in combination with bevacizumab and chemotherapy. An additional analysis of efficacy data by KRAS status did not identify a subset of patients who benefited from Vectibix in combination with oxaliplatin- or irinotecan-based chemotherapy and bevacizumab. A trend towards worse survival was observed with Vectibix in the wild-type KRAS subset of the bevacizumab and oxaliplatin cohort, and a trend towards worse survival was observed with Vectibix in the bevacizumab and irinotecan cohort regardless of KRAS mutational status. Therefore, Vectibix should not be administered in combination with bevacizumab containing chemotherapy.

Vectibix in combination with oxaliplatin-based chemotherapy in patients with mutant RAS mCRC or for whom RAS tumour status is unknown
The combination of Vectibix with oxaliplatin-containing chemotherapy is contraindicated for patients with mutant RAS mCRC or for whom RAS mCRC status is unknown.

In the primary analysis of a study (n = 1,183, 656 patients with wild-type KRAS (exon 2) and 440 patients with mutant KRAS tumours) evaluating panitumumab in combination with infusional 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) compared to FOLFOX alone as first-line therapy for mCRC, a shortened progression-free survival (PFS) and overall survival (OS) time were observed in patients with mutant KRAS tumours who received panitumumab and FOLFOX (n = 221) vs. FOLFOX alone (n = 219).

A predefined retrospective subset analysis of 641 patients of the 656 patients with wild-type KRAS (exon 2) tumours from this study identified additional RAS(KRAS [exons 3 and 4] or NRAS [exons 2, 3, 4]) mutations in 16% (n = 108) of patients. A shortening of PFS and OS was observed in patients with mutant RAStumours who received panitumumab and FOLFOX (n = 51) versus FOLFOX alone (n = 57).

RAS mutational status should be determined using a validated test method by an experienced laboratory (see section 4.2). If Vectibix is to be used in combination with FOLFOX then it is recommended that mutational status be determined by a laboratory that participates in a RAS External Quality Assurance programme or wild-type status be confirmed in a duplicate test.

Ocular toxicities
Serious cases of keratitis and ulcerative keratitis have been rarely reported in the post-marketing setting. Patients presenting with signs and symptoms suggestive of keratitis such as acute or worsening: eye inflammation, lacrimation, light sensitivity, blurred vision, eye pain and/or red eye should be referred promptly to an ophthalmology specialist.

If a diagnosis of ulcerative keratitis is confirmed, treatment with Vectibix should be interrupted or discontinued. If keratitis is diagnosed, the benefits and risks of continuing treatment should be carefully considered.

Vectibix should be used with caution in patients with a history of keratitis, ulcerative keratitis or severe dry eye. Contact lens use is also a risk factor for keratitis and ulceration.

Patients with ECOG 2 performance status treated with Vectibix in combination with 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. A positive benefit-risk balance has not been documented in patients with ECOG 2 performance status.

Elderly patients
No overall differences in safety or efficacy were observed in elderly patients (≥ 65 years of age) treated with Vectibix monotherapy. However, an increased number of serious adverse events were reported in elderly patients treated with Vectibix in combination with FOLFIRI or FOLFOX chemotherapy compared to chemotherapy alone.

Other precautions
This medicinal product contains 0.150 mmol sodium (which is 3.45 mg sodium) per ml of concentrate. To be taken into consideration by patients on a controlled sodium diet.

About Vectibix^® (panitumumab) in the U.S.
Vectibix is the first fully human monoclonal anti-epidermal growth factor receptor (EGFR) antibody approved by the U.S. Food and Drug Administration (FDA) for the treatment of mCRC. Vectibix was approved in the U.S. 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.

Important U.S. Product Information   
Vectibix^® is indicated for the treatment of patients with wild-type KRAS (exon 2 in codons 12 or 13) metastatic colorectal cancer (mCRC) as determined by an FDA-approved test for this use:

• As first-line therapy in combination with FOLFOX
• As monotherapy following disease progression after prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy

Limitation of Use: Vectibix^® is not indicated for the treatment of patients with RAS-mutant mCRC or for whom RAS mutation status is unknown.

WARNING: DERMATOLOGIC TOXICITY 
Dermatologic Toxicity: Dermatologic toxicities occurred in 90% of patients and were severe (NCI-CTC grade 3 or higher) in 15% of patients receiving Vectibix monotherapy.

In Study 1, dermatologic toxicities occurred in 90% of patients and were severe (NCI-CTC grade 3 and higher) in 15% of patients with mCRC receiving Vectibix^®. The clinical manifestations included, but were not limited to, acneiform dermatitis, pruritus, erythema, rash, skin exfoliation, paronychia, dry skin and skin fissures.

Monitor patients who develop dermatologic or soft tissue toxicities while receiving Vectibix^® for the development of inflammatory or infectious sequelae. Life-threatening and fatal infectious complications including necrotizing fasciitis, abscesses and sepsis have been observed in patients treated with Vectibix^®. Life-threatening and fatal bullous mucocutaneous disease with blisters, erosions and skin sloughing has also been observed in patients treated with Vectibix^®. It could not be determined whether these mucocutaneous adverse reactions were directly related to EGFR inhibition or to idiosyncratic immune-related effects (e.g., Stevens-Johnson syndrome or toxic epidermal necrolysis). Withhold or discontinue Vectibix^® for dermatologic or soft tissue toxicity associated with severe or life-threatening inflammatory or infectious complications. Dose modifications for Vectibix concerning dermatologic toxicity are provided in the product labeling. Vectibix^® is not indicated for the treatment of patients with colorectal cancer that harbor somatic mutations in exon 2 (codons 12 and 13), exon 3 (codons 59 and 61), and exon 4 (codons 117 and 146) of either KRAS or NRAS and hereafter is referred to as "RAS."

Retrospective subset analyses across several randomized clinical trials were conducted to investigate the role of RAS mutations on the clinical effects of anti-EGFR-directed monoclonal antibodies (panitumumab or cetuximab). Anti-EGFR antibodies in patients with tumors containing RAS mutations resulted in exposing those patients to anti-EGFR related adverse reactions without clinical benefit from these agents.

Additionally, in Study 3, 272 patients with RAS-mutant mCRC tumors received Vectibix^® in combination with FOLFOX and 276 patients received FOLFOX alone. In an exploratory subgroup analysis, OS was shorter (HR = 1.21, 95% CI 1.01-1.45) in patients with RAS-mutant mCRC who received Vectibix^® and FOLFOX versus FOLFOX alone.

Progressively decreasing serum magnesium levels leading to severe (Grade 3-4) hypomagnesemia occurred in up to 7% (in Study 2) of patients across clinical trials. Monitor patients for hypomagnesemia and hypocalcemia prior to initiating Vectibix^® treatment, periodically during Vectibix^® treatment, and for up to 8 weeks after the completion of treatment. Other electrolyte disturbances, including hypokalemia, have also been observed. Replete magnesium and other electrolytes as appropriate.

In Study 1, 4% of patients experienced infusion reactions and 1% of patients experienced severe infusion reactions (NCI-CTC grade 3-4). Infusion reactions, manifesting as fever, chills, dyspnea, bronchospasm, and hypotension, can occur following Vectibix^® administration. Fatal infusion reactions occurred in postmarketing experience. Terminate the infusion for severe infusion reactions.

Severe diarrhea and dehydration, leading to acute renal failure and other complications, have been observed in patients treated with Vectibix^® in combination with chemotherapy.

Fatal and non-fatal cases of interstitial lung disease (ILD) (1%) and pulmonary fibrosis have been observed in patients treated with Vectibix^®. Pulmonary fibrosis occurred in less than 1% (2/1467) of patients enrolled in clinical studies of Vectibix. In the event of acute onset or worsening of pulmonary symptoms, interrupt Vectibix^® therapy. Discontinue Vectibix^® therapy if ILD is confirmed.

In patients with a history of interstitial pneumonitis or pulmonary fibrosis, or evidence of interstitial pneumonitis or pulmonary fibrosis, the benefits of therapy with Vectibix^® versus the risk of pulmonary complications must be carefully considered.

Exposure to sunlight can exacerbate dermatologic toxicity. Advise patients to wear sunscreen and hats and limit sun exposure while receiving Vectibix^®.

Keratitis and ulcerative keratitis, known risk factors for corneal perforation, have been reported with Vectibix^® use. Monitor for evidence of keratitis or ulcerative keratitis. Interrupt or discontinue Vectibix^® for acute or worsening keratitis.

In an interim analysis of an open-label, multicenter, randomized clinical trial in the first-line setting in patients with mCRC, the addition of Vectibix^® to the combination of bevacizumab and chemotherapy resulted in decreased OS and increased incidence of NCI-CTC grade 3–5 (87% vs 72%) adverse reactions. NCI-CTC grade 3–4 adverse reactions occurring at a higher rate in Vectibix^®-treated patients included rash/acneiform dermatitis (26% vs 1%), diarrhea (23% vs 12%), dehydration (16% vs 5%; primarily occurring in patients with diarrhea), hypokalemia (10% vs 4%), stomatitis/mucositis (4% vs < 1%), and hypomagnesemia (4% vs 0).

NCI-CTC grade 3–5 pulmonary embolism occurred at a higher rate in Vectibix^®-treated patients (7% vs 3%) and included fatal events in three (< 1%) Vectibix^®-treated patients.

As a result of the toxicities experienced, patients randomized to Vectibix^®, bevacizumab and chemotherapy received a lower mean relative dose intensity of each chemotherapeutic agent (oxaliplatin, irinotecan, bolus 5-FU, and/or infusional 5-FU) over the first 24 weeks on study, compared with those randomized to bevacizumab and chemotherapy.

Advise patients of the need for adequate contraception in both males and females while receiving Vectibix^® and for 6 months after the last dose of Vectibix^® therapy. Vectibix^® may be transmitted from the mother to the developing fetus, and has the potential to cause fetal harm when administered to pregnant women.

Because many drugs are excreted into human milk and because of the potential for serious adverse reactions in nursing infants from Vectibix^®, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. If nursing is interrupted, it should not be resumed earlier than 2 months following the last dose of Vectibix^®.

Women who become pregnant during Vectibix^® treatment are encouraged to enroll in Amgen's Pregnancy Surveillance Program. Women who are nursing during Vectibix^® treatment are encouraged to enroll in Amgen's Lactation Surveillance Program. Patients or their physicians should call 1-800-77-AMGEN (1-800-772-6436) to enroll.

In Study 1, the most common adverse reactions (> 20%) with Vectibix^® were skin rash with variable presentations, paronychia, fatigue, nausea, and diarrhea. The most common (> 5%) serious adverse reactions in the Vectibix^® arm were general physical health deterioration and intestinal obstruction.

In Study 3, the most commonly reported adverse reactions (> 20%) in patients with wild-type KRAS mCRC receiving Vectibix^® (6 mg/kg every 2 weeks) and FOLFOX therapy (N = 322) were diarrhea, stomatitis, mucosal inflammation, asthenia, paronychia, anorexia, hypomagnesemia, hypokalemia, rash, acneiform dermatitis, pruritus and dry skin. Serious adverse reactions (> 2% difference between treatment arms) in Vectibix^®-treated patients with wild-type KRAS mCRC were diarrhea and dehydration.

About Amgen
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