In 2018, the Food and Drug Administration approved a record 58 new drugs for humans. One of these agents, Annovera (segesterone acetate and ethinyl estradiol), is a vaginal ring to prevent pregnancy and is not relevant in this article. A second drug, Asparlas (calaspargase pegol-mknl), indicated to treat acute lymphoblastic leukemia, has not yet been released by its manufacturer. The agents with molecular weights (MW) less than 1,000 probably cross the placenta, but nearly all, regardless of MW, will cross in the second half of pregnancy.
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There is no human pregnancy data for these agents, but there are five drugs included in pregnancy registries. However, it will take some time before the outcomes of these drugs are published. The routine absence of pregnancy data for most drugs was pointed out in a reference that I coauthored (“Should pregnant women be included in phase 4 clinical drug trials?” Am J Obstet Gynecol. 2015 Dec;213[6]:810-5). The article makes a strong argument for including some drugs in these trials.
Amyloidosis
Onpattro (patisiran) is indicated for the treatment of the polyneuropathy of hereditary transthyretin-mediated amyloidosis in adults. The drug caused embryo-fetal death and reduced fetal body weight in rabbits at doses also associated with maternal toxicity. No developmental toxicity was observed in rats.
Anti-infectives
Aemcolo (rifamycin), which has a MW of 720, is indicated for treatment of travelers’ diarrhea caused by noninvasive strains of Escherichia coli. No adverse fetal effects were observed in rats and rabbits that received close to human doses.
Krintafel (tafenoquine) is an antimalarial agent that is used to prevent relapse in patients who are receiving appropriate antimalarial therapy for Plasmodium vivax infection. The drug may cause hemolytic anemia in a fetus deficient in glucose-6-phosphate dehydrogenase. In rabbits, the drug caused dose-related abortions and maternal toxicity was observed in rabbits and rats. Treatment with this drug in pregnancy is not recommended, according to the manufacturer.
Tpoxx (tecovirimat monohydrate), which has a MW of about 394, is indicated for the treatment of smallpox disease. The drug did not cause embryo-fetal toxicity in pregnant mice and rabbits, but the maximum exposure in rabbits was only 0.4 times the human exposure.
Xofluza (baloxavir marboxil), which has a MW of about 572, is a prodrug that is converted by hydrolysis to baloxavir. It is indicated for the treatment of acute uncomplicated influenza. No adverse developmental effects were observed in rats and rabbits.
Zemdri (plazomicin), which has a MW of about 593, is an aminoglycoside indicated for the treatment of complicated urinary tract infections including pyelonephritis. The drug did not cause fetal harm in rats and rabbits at doses that did not cause maternal toxicity; however, prolonged use of an aminoglycoside (such as streptomycin) has caused irreversible, bilateral congenital deafness in children exposed in utero to prolonged use and is a potential complication.
Three new drugs in 2018 are indicated for treating HIV-1:
Biktarvy is a three-drug combination that includes bictegravir, emtricitabine, and tenofovir. The latter two drugs are included in the 11th edition of my book (“Drugs in Pregnancy and Lactation,” 11th ed. [Riverwoods, Ill.: Wolters Kluwer, 2017) and are not included here. Both are classified as compatible in pregnancy. Bictegravir has a MW of about 471. No adverse embryo-fetal effects in rats and rabbits were observed with this agent.
Trogarzo (ibalizumab-uiyk), which has a MW of about 150,000, is a monoclonal antibody antiretroviral agent used in combination with other antiretrovirals. There are no animal data. Although the MW is very high, monoclonal antibodies are transported across the placenta as pregnancy progresses.
Pifeltro (doravirine), which has a MW of about 426, is a nonnucleoside reverse transcriptase inhibitor used in combination with other antiretroviral agents for the treatment of HIV-1. The drug caused no significant toxicologic effects on embryo-fetal rats and rabbits.
Gerald G. Briggs
If Biktarvy, Pifeltro, or Trogarzo are used in pregnancy, health care providers are encouraged to register the patient in the Antiretroviral Pregnancy Registry by calling 1-800-258-4263.
There are three new agents in the tetracycline class.
Nuzyra (omadacycline), which has a MW of about 729, is for community-acquired bacterial pneumonia and acute bacterial skin and skin structure infections.
Seysara (sarecycline), which has a MW of about 524, is for inflammatory lesions of nonnodular, moderate to severe acne vulgaris.
Xerava (eravacycline), which has a MW of about 632, is for complicated intra-abdominal infection.
The various dose-related toxicities observed with the three drugs in rats and rabbits included maternal deaths; increased postimplantation loss; reduced fetal body weights; delays in skeletal ossification; and fetal malformations of the skeleton, heart, and lung. Use of these drugs in the last half of pregnancy may cause permanent discoloration of the teeth and enamel hypoplasia, as well as inhibition of bone growth.