Panitumumab

The Basics

What is Panitumumab?

Used to treat a certain type of metastatic colorectal cancer that has progressed after treatment with other chemotherapy.

Brand names for Panitumumab

Vectibix

How Panitumumab is classified

Antibodies – Monoclonal

Panitumumab During Pregnancy

Panitumumab pregnancy category

Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Panitumumab while pregnant

There are no studies of Vectibix in pregnant women. Reproduction studies in cynomolgus monkeys treated with 1.25 to 5 times the recommended human dose of panitumumab resulted in significant embryolethality and abortions; however, no other evidence of teratogenesis was noted in offspring [see Nonclinical Toxicology]. Vectibix should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Based on animal models, EGFR is involved in prenatal development and may be essential for normal organogenesis, proliferation, and differentiation in the developing embryo. Human IgG is known to cross the placental barrier; therefore, panitumumab may be transmitted from the mother to the developing fetus, and has the potential to cause fetal harm when administered to pregnant women. Women who become pregnant during Vectibix treatment are encouraged to enroll in Amgen’s Pregnancy Surveillance Program. Patients or their physicians should call 1-800-77-AMGEN (1-800-772-6436) to enroll.

Taking Panitumumab While Breastfeeding

What are recommendations for lactation if you're taking Panitumumab?

No information is available on the clinical use of panitumumab during breastfeeding. Because panitumumab is a large protein molecule with a molecular weight of about 147,000, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant’s gastrointestinal tract. Until more data become available, panitumumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. The manufacturer recommends that breastfeeding be discontinued during panitumumab therapy and for 2 months after the final dose. Panitumumab is a human immunoglobulin G2 (IgG2) kappa antibody. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous immunoglobulin G by up to 79%.[1][2] A study of 67 colostrum samples that underwent Holder pasteurization found that IgG amounts decreased by 34 to 40%. Specific IgG subclasses decreased by different amounts, with IgG2 activity decreasing by about 50%.[3] None of the studies measured IgG activity.

Maternal / infant drug levels

No information is available on the clinical use of panitumumab during breastfeeding. Because panitumumab is a large protein molecule with a molecular weight of about 147,000, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant’s gastrointestinal tract. Until more data become available, panitumumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. The manufacturer recommends that breastfeeding be discontinued during panitumumab therapy and for 2 months after the final dose. Panitumumab is a human immunoglobulin G2 (IgG2) kappa antibody. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous immunoglobulin G by up to 79%.[1][2] A study of 67 colostrum samples that underwent Holder pasteurization found that IgG amounts decreased by 34 to 40%. Specific IgG subclasses decreased by different amounts, with IgG2 activity decreasing by about 50%.[3] None of the studies measured IgG activity.

Possible effects of Panitumumab on milk supply

Relevant published information was not found as of the revision date.

Possible alternatives to Panitumumab

None listed