Vectibix Side Effects

Generic Name: panitumumab

Please note - some side effects for Vectibix may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Side Effects of Vectibix - for the Consumer

Vectibix

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Vectibix:

Constipation; diarrhea; eyelash growth; mild acne; mild dryness, itching, or redness of the skin; nausea; stomach pain; tiredness; vomiting.

Seek medical attention right away if any of these SEVERE side effects occur when using Vectibix:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue; unusual hoarseness); chest congestion or tightness; chest pain; cough; increased tearing; irritation, pain, redness, or swelling of the eye or eyelid; irritation, redness, swelling, or sores in or around the mouth; moderate to severe skin changes (eg, blistered, cracking, peeling, swollen, or painful skin; moderate to severe acne; moderate to severe redness or itching); pain, redness, or swelling at the injection site; pain, redness, or swelling near the nailbed; severe or persistent diarrhea, nausea, or vomiting; shortness of breath; signs of infection (eg, chills, fever, sore throat); swelling of the ankles, feet, or hands; vision changes; wheezing.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

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Vectibix Side Effects - for the Professional

Vectibix

The following adverse reactions are discussed in greater detail in other sections of the label:

• Dermatologic Toxicity [see Boxed Warning, Dosage and Administration (2.1), and Warnings and Precautions (5.1)]
• Infusion Reactions [see Boxed Warning, Dosage and Administration (2.1), and Warnings and Precautions (5.2)]
• Increased Toxicity With Combination Chemotherapy [see Warnings and Precautions (5.3)]
• Pulmonary Fibrosis [see Warnings and Precautions (5.4)]
• Electrolyte Depletion/Monitoring [see Warnings and Precautions (5.5)]
• Photosensitivity [see Warnings and Precautions (5.6)]

The most common adverse events of Vectibix are skin rash with variable presentations, hypomagnesemia, paronychia, fatigue, abdominal pain, nausea, and diarrhea, including diarrhea resulting in dehydration.

The most serious adverse events 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. Adverse reactions requiring discontinuation of Vectibix were infusion reactions, severe skin toxicity, paronychia, and pulmonary fibrosis.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates in the clinical trials of a drug cannot be directly compared to rates in clinical trials of another drug and may not reflect the rates observed in practice. The adverse reaction information from clinical studies does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates.

Safety data are available from 15 clinical trials in which 1467 patients received Vectibix; of these, 1293 received Vectibix monotherapy and 174 received Vectibix in combination with chemotherapy [see Warnings and Precautions (5.3)].

The data described in Table 1 and in other sections below, except where noted, reflect exposure to Vectibix administered as a single agent at the recommended dose and schedule (6 mg/kg every 2 weeks) in 229 patients with mCRC enrolled in Study 1, a randomized, controlled trial. The median number of doses was five (range: one to 26 doses), and 71% of patients received eight or fewer doses. The population had a median age of 62 years (range: 27 to 82 years), 63% were male, and 99% were white with < 1% black, < 1% Hispanic, and 0% other.

Table 1. Per-Patient Incidence of Adverse Reactions Occurring in ≥ 5% of Patients With a Between-Group Difference of ≥ 5% (Study 1)

* Version 2.0 of the NCI-CTC was used for grading toxicities. Skin toxicity was coded based on a modification of the NCI-CTCAE, version 3.0.
	Patients Treated With Vectibix Plus BSC (n = 229)		Best Supportive Care (BSC) Alone (n = 234)
	Grade*
Body System	All Grades (%)	Grade 3-4 (%)	All Grades (%)	Grade 3-4 (%)
Body as a Whole
Fatigue	26	4	15	3
General Deterioration	11	8	4	3
Digestive
Abdominal Pain	25	7	17	5
Nausea	23	1	16	< 1
Diarrhea	21	2	11	0
Constipation	21	3	9	1
Vomiting	19	2	12	1
Stomatitis	7	0	1	0
Mucosal Inflammation	6	< 1	1	0
Metabolic/Nutritional
Hypomagnesemia (Lab)	38	4	2	0
Peripheral Edema	12	1	6	< 1
Respiratory
Cough	14	< 1	7	0
Skin/Appendages
All Skin/Integument Toxicity	90	16	9	0
Skin	90	14	6	0
Erythema	65	5	1	0
Dermatitis Acneiform	57	7	1	0
Pruritus	57	2	2	0
Nail	29	2	0	0
Paronychia	25	2	0	0
Skin Exfoliation	25	2	0	0
Rash	22	1	1	0
Skin Fissures	20	1	< 1	0
Eye	15	< 1	2	0
Acne	13	1	0	0
Dry Skin	10	0	0	0
Other Nail Disorder	9	0	0	0
Hair	9	0	1	0
Growth of Eyelashes	6	0	0	0

Dermatologic, Mucosal, and Ocular Toxicity

In Study 1, dermatologic toxicities occurred in 90% of patients receiving Vectibix. Skin toxicity was severe (NCI-CTC grade 3 and higher) in 16% of patients. Ocular toxicities occurred in 15% of patients and included, but were not limited to conjunctivitis (4%), ocular hyperemia (3%), increased lacrimation (2%), and eye/eyelid irritation (1%). Stomatitis (7%) and oral mucositis (6%) were reported. One patient experienced an NCI-CTC grade 3 event of mucosal inflammation. The incidence of paronychia was 25% and was severe in 2% of patients. Nail disorders occurred in 9% of patients [see Warnings and Precautions (5.1)].

Median time to the development of dermatologic, nail, or ocular toxicity was 14 days after the first dose of Vectibix; the median time to most severe skin/ocular toxicity was 15 days after the first dose of Vectibix; and the median time to resolution after the last dose of Vectibix was 84 days. Severe toxicity necessitated dose interruption in 11% of Vectibix-treated patients [see Dosage and Administration (2.1)].

Subsequent to the development of severe dermatologic toxicities, infectious complications, including sepsis, septic death, necrotizing fasciitis, and abscesses requiring incisions and drainage, were reported.

Infusion Reactions

Infusional toxicity was defined as any event within 24 hours of an infusion during the clinical study described as allergic reaction or anaphylactoid reaction, or any event occurring on the first day of dosing described as allergic reaction, anaphylactoid reaction, fever, chills, or dyspnea. Vital signs and temperature were measured within 30 minutes prior to initiation and upon completion of the Vectibix infusion. The use of premedication was not standardized in the clinical trials. Thus, the utility of premedication in preventing the first or subsequent episodes of infusional toxicity is unknown. Across several clinical trials of Vectibix monotherapy, 3% (43/1336) experienced infusion reactions of which approximately 1% (6/1336) were severe (NCI-CTC grade 3–4). In one patient, Vectibix was permanently discontinued for a serious infusion reaction [see Dosage and Administration (2.1)].

Immunogenicity

As with all therapeutic proteins, there is potential for immunogenicity. The immunogenicity of Vectibix has been evaluated using two different screening immunoassays for the detection of anti-panitumumab antibodies: an acid dissociation bridging enzyme-linked immunosorbent assay (ELISA) (detecting high-affinity antibodies) and a Biacore® biosensor immunoassay (detecting both high- and low-affinity antibodies). The incidence of binding antibodies to panitumumab (excluding predose and transient positive patients), as detected by the acid dissociation ELISA, was 3/613 (< 1%) and as detected by the Biacore® assay was 28/613 (4.6%).

For patients whose sera tested positive in screening immunoassays, an in vitro biological assay was performed to detect neutralizing antibodies. Excluding predose and transient positive patients, 10/613 patients (1.6%) with postdose samples and 3/356 (0.8%) of the patients with follow-up samples tested positive for neutralizing antibodies. 

No evidence of altered pharmacokinetic profile or toxicity profile was found between patients who developed antibodies to panitumumab as detected by screening immunoassays and those who did not.

The incidence of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to panitumumab with the incidence of antibodies to other products may be misleading.

Postmarketing Experience

The following adverse reaction has been identified during post-approval use of panitumumab. Because these reactions are reported in a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• Skin and subcutaneous tissue disorders: Angioedema [see Boxed Warning, Dosage and Administration (2.1), and Warnings and Precautions (5.2)]
• Skin and subcutaneous tissue disorders: Skin necrosis
• Immune system disorders: Anaphylactoid reaction [see Boxed Warning, Dosage and Administration (2.1), and Warnings and Precautions (5.2)]
• Eye disorders: Keratitis/ulcerative keratitis [see Warnings and Precautions (5.7)]

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Side Effects by Body System - for Healthcare Professionals

Dermatologic

Dermatologic side effects including all skin/integument toxicity (90%), erythema (65%), acneiform dermatitis (57%), pruritus (57%), skin exfoliation (25%), paronychia (25%), rash (22%), skin fissures (20%), acne (13%), dry skin (10%), nail disorders (9%), and growth of eyelashes (6%) have been reported.

Dermatologic toxicities related to the panitumumab blockade of EGF binding and subsequent inhibition of EGFR-mediated signaling were severe in 16% of patients with metastatic colorectal cancer receiving panitumumab. Subsequent to the development of severe dermatologic toxicities infectious complications including sepsis, septic death, and abscesses requiring incisions and drainage were reported.

Animal studies have reported dermatologic findings, including dermatitis, pustule formation, exfoliative rash, and deaths secondary to bacterial infection and sepsis.

General

General side effects including fatigue (26%) and general deterioration (11%) have been reported.

Gastrointestinal

When used in combination with irinotecan, the incidence and severity of diarrhea is increased. In a study of 19 patients who received panitumumab in combination with irinotecan, 5-fluorouracil, and leucovorin, the incidence of grade 3 or 4 diarrhea was 58% and was fatal in one patient. The combination of panitumumab with leucovorin is not recommended.

Gastrointestinal side effects including abdominal pain (25%), nausea (23%), diarrhea (21%), constipation (21%), vomiting (19%), stomatitis (7%), and mucosal inflammation (6%) have been reported.

Metabolic

Metabolic side effects including hypomagnesemia (39%) and peripheral edema (12%) have been reported.

Median magnesium levels decreased by 0.1 mmol/L. Hypomagnesemia (grade 3 or 4) requiring oral or IV electrolyte repletion occurred in 2% of patients. Hypomagnesemia occurred 6 weeks or longer after the initiation of panitumumab. In some patients, hypomagnesemia was associated with hypocalcemia. Patient's electrolytes should be monitored during and for eight weeks after the completion of panitumumab therapy. Patients should be periodically monitored for hypomagnesemia and accompanying hypocalcemia during the eight weeks after the completion of panitumumab therapy.

Respiratory

Panitumumab should be permanently discontinued in patients developing interstitial lung disease, pneumonitis, or lung infiltrates.

Respiratory side effects including cough (14%), pulmonary embolism, and pulmonary fibrosis (reported in less than 1%) have been reported.

Ocular

Ocular side effects (15%) have been reported.

Hypersensitivity

Hypersensitivity side effects have been reported. Four percent of patients have experienced an infusion reaction and 1% of those were severe.

Severe infusion reactions were identified as anaphylactic reaction, bronchospasm, fever, chills, and hypotension. Although fatal infusion reactions have not been reported with panitumumab, fatalities have occurred with other monoclonal antibody products. The infusion should be stopped if a severe infusion reaction occurs. Depending on the severity and/or persistence of the reaction, panitumumab may need to be permanently discontinued.

Cardiovascular

Cardiovascular side effects including angioedema have been reported.

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