Medical Editor: John P. Cunha, DO, FACOEP
Vectibix (panitumumab) Injection is a cancer medication used to treat metastatic colorectal cancer that has progressed after treatment with other chemotherapy. Common side effects of Vectibix include:
- skin reactions (redness, acne, itching, or rash)
- diarrhea
- nausea
- vomiting
- tiredness
- constipation
- stomach or abdominal pain, or
- growth of eyelashes
The recommended dose of Vectibix is 6 mg/kg, administered as an intravenous infusion over 60 minutes, every 14 days. Doses higher than 1000 mg should be administered over 90 minutes. Vectibix may interact with other drugs. Tell your doctor all medications and supplements you use. Vectibix is not recommended for use during pregnancy. It may harm a fetus. Consult your doctor to discuss using at least 2 forms of birth control (e.g., condoms, birth control pills) while receiving this medication and for 6 months after the end of treatment. If you become pregnant or think you may be pregnant, tell your doctor. Based on information from related drugs, this medication may pass into breast milk. Breastfeeding is not recommended while using Vectibix and for 2 months after the end of treatment.
Our Vectibix (panitumumab) Injection Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

QUESTION
What are risk factors for developing colon cancer? See AnswerGet emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Some side effects may occur during the injection. Tell your caregiver right away if you feel dizzy, nauseated, light-headed, chilled, feverish, or have chest tightness or trouble breathing.
Seek emergency medical attention at the first sign of any skin rash. Panitumumab may cause severe skin problems that can lead to widespread infection and possibly death.
Call your doctor at once if you have:
- severe or ongoing diarrhea;
- sudden chest pain or discomfort, wheezing, dry cough or hack, feeling short of breath;
- redness, swelling, or irritation of your eyes or eyelids, vision changes;
- swelling in your face;
- low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling;
- dehydration symptoms--feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin;
- signs of a kidney problem--little or no urinating; painful or difficult urination; swelling in your feet or ankles; feeling tired or short of breath; or
- skin problems--severe or worsening acne, swelling or infection around your fingernails or toenails, skin itching, redness, dryness, peeling, cracking, or oozing.
Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.
Common side effects may include:
- acne, dry skin, rash, itching;
- swelling or irritation around your fingernails or toenails;
- loss of appetite, nausea, diarrhea;
- blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;
- tired feeling, weakness; or
- low potassium.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Read the entire detailed patient monograph for Vectibix (Panitumumab Injection for Intravenous Use)

SLIDESHOW
Digestive Disorders: Common Misconceptions See SlideshowSIDE EFFECTS
The following adverse reactions are discussed in greater detail in other sections of the label:
- Dermatologic and Soft Tissue Toxicity [see BOXED WARNING, DOSAGE AND ADMINISTRATION, and WARNINGS AND PRECAUTIONS]
- Increased Tumor Progression, Increased Mortality, or Lack of Benefit in KRAS-Mutant mCRC [see INDICATIONS AND USAGE and WARNINGS AND PRECAUTIONS]
- Electrolyte Depletion/Monitoring [see WARNINGS AND PRECAUTIONS]
- Infusion Reactions [see DOSAGE AND ADMINISTRATION, and WARNINGS AND PRECAUTIONS]
- Acute Renal Failure in Combination with Chemotherapy [see WARNINGS AND PRECAUTIONS]
- Pulmonary Fibrosis/Interstitial Lung Disease (ILD) [see WARNINGS AND PRECAUTIONS]
- Photosensitivity [see WARNINGS AND PRECAUTIONS]
- Ocular Toxicities [see WARNINGS AND PRECAUTIONS]
- Increased Mortality and Toxicity with Vectibix in combination with Bevacizumab and Chemotherapy [see WARNINGS AND PRECAUTIONS]
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 presented from two clinical trials in which patients received Vectibix: Study 1, an open-label, multinational, randomized, controlled, monotherapy clinical trial (N = 463) evaluating Vectibix with best supportive care (BSC) versus BSC alone in patients with EGFR-expressing mCRC and Study 3, a randomized, controlled trial (N = 1183) in patients with mCRC that evaluated Vectibix in combination with FOLFOX chemotherapy versus FOLFOX chemotherapy alone. Safety data for Study 3 are limited to 656 patients with wild-type KRAS mCRC.
Vectibix Monotherapy
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. The most frequently reported adverse reactions for Vectibix leading to withdrawal were general physical health deterioration (n = 2) and intestinal obstruction (n = 2).
For Study 1, the data described in Table 1 and in other sections below, except where noted, reflect exposure to Vectibix administered to patients with mCRC as a single agent at the recommended dose and schedule (6 mg/kg every 2 weeks).
Table 1: Adverse Reactions ( ≥ 5% Difference)
Observed in Patients Treated with Vectibix Monotherapy and Best Supportive Care
Compared to Best Supportive Care Alone (Study 1)
SYSTEM ORGAN CLASS Preferred Term | Study 1 | |||
Vectibix Plus Best Supportive Care (N = 229) |
Best Supportive Care (N = 234) |
|||
Any Grade n (%) |
Grade 3-4 n (%) |
Any Grade n (%) |
Grade 3-4 n (%) |
|
EYE DISORDERS | ||||
Growth of eyelashes | 13 (6) | |||
GASTROINTESTINAL DISORDERS | ||||
Nausea | 52 (23) | 2 ( < 1) | 37 (16) | 1 ( < 1) |
Diarrhea | 49 (21) | 4 (2) | 26 (11) | |
Vomiting | 43 (19) | 6 (3) | 28 (12) | 2 ( < 1) |
Stomatitis | 15 (7) | 2 ( < 1) | ||
GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS | ||||
Fatigue | 60 (26) | 10 (4) | 34 (15) | 7 (3) |
Mucosal inflammation | 15 (7) | 1 ( < 1) | 2 ( < 1) | |
INFECTIONS AND INFESTATIONS | ||||
Paronychia | 57 (25) | 4 (2) | ||
RESPIRATORY, THORACIC, AND MEDIASTINAL DISORDERS | ||||
Dyspnea | 41 (18) | 12 (5) | 30 (13) | 8 (3) |
Cough | 34 (15) | 1 ( < 1) | 17 (7) | |
SKIN AND SUBCUTANEOUS TISSUE DISORDERS | ||||
Erythema | 150 (66) | 13 (6) | 2 ( < 1) | |
Pruritus | 132 (58) | 6 (3) | 4 (2) | |
Acneiform dermatitis | 131 (57) | 17 (7) | 2 ( < 1) | |
Rash | 51 (22) | 3 (1) | 2 ( < 1) | |
Skin fissures | 45 (20) | 3 (1) | 1 ( < 1) | |
Exfoliative rash | 41 (18) | 4 (2) | ||
Acne | 31(14) | 3 (1) | ||
Dry skin | 23 (10) | |||
Nail disorder | 22 (10) | |||
Skin exfoliation | 21 (9) | 2 ( < 1) | ||
Skin ulcer | 13 (6) | 1 ( < 1) |
Adverse reactions in Study 1 that did not meet the threshold criteria for inclusion in Table 1 were conjunctivitis (4.8% vs < 1%), dry mouth (4.8% vs 0%), pyrexia (16.6% vs 13.2%), chills (3.1% vs < 1%), pustular rash (4.4% vs 0%), papular rash (1.7% vs 0%), dehydration (2.6% vs 1.7%), epistaxis (3.9% vs 0%), and pulmonary embolism (1.3% vs 0%).
In Study 1, dermatologic toxicities occurred in 90% of patients receiving Vectibix. Skin toxicity was severe (NCICTC grade 3 and higher) in 15% of patients. Ocular toxicities occurred in 16% of patients and included, but were not limited to, conjunctivitis (5%). 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 [see WARNINGS AND PRECAUTIONS].
In Study 1 (N = 229), median time to the development of dermatologic, nail, or ocular toxicity was 12 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 98 days. Severe toxicity necessitated dose interruption in 11% of Vectibix-treated patients [see DOSAGE AND ADMINISTRATION].
Subsequent to the development of severe dermatologic toxicities, infectious complications, including sepsis, septic death, necrotizing fasciitis, and abscesses requiring incisions and drainage were reported.
Vectibix in Combination with FOLFOX Chemotherapy
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) in Study 3 were diarrhea, stomatitis, mucosal inflammation, asthenia, paronychia, anorexia, hypomagnesemia, hypokalemia, rash, acneiform dermatitis, pruritus, and dry skin (Table 2). Serious adverse reactions ( ≥ 2% difference between treatment arms) in Vectibix-treated patients with wild-type KRAS mCRC were diarrhea and dehydration. The commonly reported adverse reactions ( ≥ 1%) leading to discontinuation in patients with wild-type KRAS mCRC receiving Vectibix were rash, paresthesia, fatigue, diarrhea, acneiform dermatitis, and hypersensitivity. One grade 5 adverse reaction, hypokalemia, occurred in a patient who received Vectibix.
Table 2: Adverse Reactions ( ≥ 5% Difference)
Observed in Patients with Wild-type (WT) KRAS Tumors Treated with Vectibix and
FOLFOX Chemotherapy Compared to FOLFOX Chemotherapy Alone (Study 3)
SYSTEM ORGAN CLASS Preferred Term |
Vectibix Plus FOLFOX (n = 322) |
FOLFOX Alone (n = 327) |
||
Any Grade n (%) |
Grade 3-4 n (%) |
Any Grade n (%) |
Grade 3-4 n (%) |
|
EYE DISORDERS | ||||
Conjunctivitis | 58 (18) | 5 (2) | 10 (3) | |
GASTROINTESTINAL DISORDERS | ||||
Diarrhea | 201 (62) | 59 (18) | 169 (52) | 29 (9) |
Stomatitis | 87 (27) | 15 (5) | 42 (13) | 1 ( < 1) |
GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS | ||||
Mucosal inflammation | 82 (25) | 14 (4) | 53(16) | 1 ( < 1) |
Asthenia | 79 (25) | 16 (5) | 62 (19) | 11 (3) |
INFECTIONS AND INFESTATIONS | ||||
Paronychia | 68 (21) | 11 (3) | ||
INVESTIGATIONS | ||||
Weight decreased | 58 (18) | 3 ( < 1) | 22 (7) | |
METABOLISM AND NUTRITION DISORDERS | ||||
Anorexia | 116 (36) | 14 (4) | 85 (26) | 6 (2) |
Hypomagnesemia | 96 (30) | 21 (7) | 26 (8) | 1 ( < 1) |
Hypokalemia | 68 (21) | 32 (10) | 42 (13) | 15 (5) |
Dehydration | 26 (8) | 8 (2) | 10 (3) | 5 (2) |
RESPIRATORY, THORACIC, AND MEDIASTINAL DISORDERS | ||||
Epistaxis | 46 (14) | 30 (9) | ||
SKIN AND SUBCUTANEOUS TISSUE DISORDERS | ||||
Rash | 179 (56) | 55 (17) | 24 (7) | 1 ( < 1) |
Acneiform dermatitis | 104 (32) | 33 (10) | ||
Pruritus | 75 (23) | 3 ( < 1) | 14 (4) | |
Dry skin | 68 (21) | 5 (2) | 13 (4) | |
Erythema | 50 (16) | 7 (2) | 14 (4) | |
Skin fissures | 50 (16) | 1 ( < 1) | 1 ( < 1) | |
Alopecia | 47 (15) | 30 (9) | ||
Acne | 44 (14) | 10 (3) | 1 ( < 1) | |
Nail disorder | 32 (10) | 4 (1) | 4 (1) | |
Palmar-plantar erythrodysesthesia syndrome | 30 (9) | 4 (1) | 9 (3) | 2 ( < 1) |
Adverse reactions that did not meet the threshold criteria for inclusion in Table 2 were abdominal pain (28% vs 23%), localized infection (3.7% vs < 1%), cellulitis (2.5% vs 0%), hypocalcemia (5.6% vs 2.1%), and deep vein thrombosis (5.3% vs 3.1%).
Infusion Reactions
Infusional toxicity manifesting as fever, chills, dyspnea, bronchospasm or hypotension was assessed within 24 hours of an infusion during the clinical study. 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 clinical trials of Vectibix monotherapy, 3% (24/725) experienced infusion reactions of which < 1% (3/725) were severe (NCI-CTC grade 3-4). In one patient, Vectibix was permanently discontinued for a serious infusion reaction [see DOSAGE AND ADMINISTRATION].
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 binding 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. For patients whose sera tested positive in screening immunoassays, an in vitro biological assay was performed to detect neutralizing antibodies.
Monotherapy
The incidence of binding anti-panitumumab antibodies (excluding preexisting and transient positive patients) was 0.4% (5/1123) as detected by the acid dissociation ELISA and 3.2% (36/1123) as detected by the Biacore® assay. The incidence of neutralizing anti-panitumumab antibodies (excluding preexisting and transient positive patients) was 0.8% (9/1123). There was no evidence of altered pharmacokinetic or safety profiles in patients who developed antibodies to Vectibix.
In combination with chemotherapy: The incidence of binding anti-panitumumab antibodies (excluding preexisting positive patients) was 0.9% (12/1297) as detected by the acid dissociation ELISA and 0.7% (9/1296) as detected by the Biacore® assay. The incidence of neutralizing anti-panitumumab antibodies (excluding preexisting positive patients) was 0.2% (2/1297). No evidence of an altered safety profile was found in patients who developed antibodies to Vectibix.
The detection 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 reactions have been identified during post-approval use of Vectibix. 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: Skin necrosis, angioedema [see BOXED WARNING, DOSAGE AND ADMINISTRATION, and WARNINGS AND PRECAUTIONS]
- Immune system disorders: Infusion reaction [see DOSAGE AND ADMINISTRATION and WARNINGS AND PRECAUTIONS]
- Eye disorders: Keratitis/ulcerative keratitis [see WARNINGS AND PRECAUTIONS]
Read the entire FDA prescribing information for Vectibix (Panitumumab Injection for Intravenous Use)
© Vectibix Patient Information is supplied by Cerner Multum, Inc. and Vectibix Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.
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