Vectibix Adverse Reactions

Summary of safety profile: Based on an analysis of mCRC clinical trial patients receiving VECTIBIX monotherapy and in combination with chemotherapy (n = 2,224), adverse reactions occurring in ≥ 20% of patients were gastrointestinal disorders [diarrhea (46%), nausea (39%), vomiting (26%), abdominal pain (23%) and constipation (23%)]; general disorders [fatigue (35%) and pyrexia (21%)]; infections and infestations [paronychia (20%)]; metabolism and nutrition disorders [decreased appetite (30%)]; and skin and subcutaneous disorders [rash (47%), dermatitis acneiform (39%), pruritus (36%), erythema (33%) and dry skin (21%)].
Tabulated summary of adverse reactions: Adverse reactions are presented in table as follows by system organ class and frequency category. Frequency categories were determined from the crude incidence rate reported for each adverse reaction in a dataset of pooled clinical studies (N = 2,224). (See Tables 9a and 9b.)

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Postmarketing Experience: The following serious adverse reactions have been reported in the postmarketing setting: corneal perforation^a; skin necrosis; Stevens-Johnson syndrome; toxic epidermal necrolysis; ulcerative keratitis.
^a Corneal perforation includes keratorhexis and corneal perforation.
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) and a Biacore biosensor immunoassay. For patients whose sera tested positive in either screening immunoassay, an in vitro biological assay was performed to detect neutralizing antibodies.
As monotherapy: The incidence of binding antibodies (excluding predose and transient positive patients) was < 1% as detected by the acid-dissociation ELISA and 3.3% as detected by the Biacore assay.
The incidence of neutralizing antibodies (excluding predose and transient positive patients) was < 1%.
There was no evidence of altered pharmacokinetic or toxicity profiles in patients who developed antibodies to VECTIBIX.
In combination with irinotecan- or oxaliplatin-based chemotherapy [Optional wild-type KRAS incidences are presented in brackets]: The incidence of binding antibodies (excluding predose positive patients) was 1.0% [(1.2% in patients with wild-type KRAS mCRC)] as detected by the acid-dissociation ELISA and < 1% [(< 1% in patients with wild-type KRAS mCRC)] as detected by the Biacore assay.
The incidence of neutralizing antibodies (excluding predose positive patients) was < 1% [(< 1% in patients with wild-type KRAS mCRC)].
No evidence of an altered safety profile was found in patients who tested positive for 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 subject incidence of antibodies to other products may be misleading.