Trastuzumab

The Basics

What is Trastuzumab?

Used to treat HER2-positive breast cancer.

Brand names for Trastuzumab

Herceptin

How Trastuzumab is classified

Antibodies – Monoclonal, Antineoplastic Agents

Trastuzumab During Pregnancy

Trastuzumab pregnancy category

Category N/ANote 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 Trastuzumab while pregnant

HERCEPTIN HYLECTA can cause fetal harm when administered to a pregnant woman. In post-marketing, reports, use of trastuzumab during pregnancy resulted in cases of oligohydramnios and of oligohydramnios, sequence, manifesting as pulmonary hypoplasia, skeletal abnormalities, and neonatal death (see Data). Apprise, the patient of the potential risks to a fetus. There are clinical considerations if HERCEPTIN HYLECTA is used, in a pregnant woman or if a patient becomes pregnant within 7 months following the last dose of HERCEPTIN, HYLECTA (see Clinical Considerations)., The estimated background risk of major birth defects and miscarriage for the indicated population is unknown., In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically, recognized pregnancies is 2 to 4% and 15 to 20%, respectively. In post-marketing reports, use of trastuzumab during pregnancy resulted in cases of oligohydramnios and of, oligohydramnios sequence, manifesting in the fetus as pulmonary hypoplasia, skeletal abnormalities, and neonatal death. These case reports described oligohydramnios in pregnant women who received trastuzumab either alone, or in combination with chemotherapy. In some case reports, amniotic fluid index increased after use of, trastuzumab was stopped. In one case, therapy with trastuzumab resumed after amniotic index improved and, oligohydramnios recurred. There is a pregnancy pharmacovigilance program for Herceptin. If Herceptin is administered during pregnancy, or if a patient becomes pregnant while receiving Herceptin or within 7 months following the last dose of Herceptin, health care providers and patients should immediately report Herceptin exposure to Genentech at 1-888-835-2555. Risk Summary Herceptin can cause fetal harm when administered to a pregnant woman. In post-marketing reports, use of Herceptin during pregnancy resulted in cases of oligohydramnios and of oligohydramnios sequence, manifesting as pulmonary hypoplasia, skeletal abnormalities, and neonatal death . Apprise the patient of the potential risks to a fetus. There are clinical considerations if Herceptin is used in a pregnant woman or if a patient becomes pregnant within 7 months following the last dose of Herceptin [see Clinical Considerations]. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Monitor women who received Herceptin during pregnancy or within 7 months prior to conception for oligohydramnios. If oligohydramnios occurs, perform fetal testing that is appropriate for gestational age and consistent with community standards of care. Data Human Data In post-marketing reports, use of Herceptin during pregnancy resulted in cases of oligohydramnios and of oligohydramnios sequence, manifesting in the fetus as pulmonary hypoplasia, skeletal abnormalities, and neonatal death. These case reports described oligohydramnios in pregnant women who received Herceptin either alone or in combination with chemotherapy. In some case reports, amniotic fluid index increased after Herceptin was stopped. In one case, Herceptin therapy resumed after amniotic index improved and oligohydramnios recurred. Animal Data In studies where trastuzumab was administered to pregnant Cynomolgus monkeys during the period of organogenesis at doses up to 25 mg/kg given twice weekly (up to 25 times the recommended weekly human dose of 2 mg/kg), trastuzumab crossed the placental barrier during the early (Gestation Days 20 to 50) and late (Gestation Days 120 to 150) phases of gestation. The resulting concentrations of trastuzumab in fetal serum and amniotic fluid were approximately 33% and 25%, respectively, of those present in the maternal serum but were not associated with adverse developmental effects.

Taking Trastuzumab While Breastfeeding

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

No information is available on the clinical use of trastuzumab during breastfeeding. Because trastuzumab is a large protein molecule with a molecular weight of 145,531, 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, trastuzumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.[1] The manufacturer recommends that breastfeeding be discontinued during trastuzumab therapy and for 7 months after the last dose. Trastuzumab is a human immunoglobulin G1 (IgG1) kappa antibody. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous immunoglobulin G by up to 79%.[2][3] 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 IgG1 activity decreasing by about 37%.[4] None of the studies measured IgG activity.

Maternal / infant drug levels

No information is available on the clinical use of trastuzumab during breastfeeding. Because trastuzumab is a large protein molecule with a molecular weight of 145,531, 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, trastuzumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.[1] The manufacturer recommends that breastfeeding be discontinued during trastuzumab therapy and for 7 months after the last dose. Trastuzumab is a human immunoglobulin G1 (IgG1) kappa antibody. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous immunoglobulin G by up to 79%.[2][3] 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 IgG1 activity decreasing by about 37%.[4] None of the studies measured IgG activity.

Possible effects of Trastuzumab on milk supply

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

Possible alternatives to Trastuzumab

None listed