Introduction/Background Lung cancer incidence is increasing in pregnancy, partially related to advanced maternal age. A subset of patients with non-small cell lung cancer (NSCLC) harbor an Anaplastic Lymphoma Kinase (ALK) gene rerrangement. ALK-inhibitors, such as Alectinib, are promising drug to treat ALK-rearranged NSCLC, but rare safety data regarding use during pregnancy are known.

Methodology We report our experience in management of two patients treated with Alectinib during pregnancy for advanced ALK rearranged lung cancer, between 2018 and 2022.

Results In 2018, a 31 years old women affected of metastatic ALK-rearranged lung cancer treated with Alectinib 600 mg twice daily became pregnant by spontaneous conception. The case, occurred to our attention at 7 weeks of pregnancy, was discussed within a multidisciplinary team: the patient decided to continue pregnancy and full-dose treatment. Mother and fetus were subjected to careful clinical and instrumental investigations until delivery. We determined the levels of Alectinib in placenta, amniotic fluid, maternal plasma and cord-derived fetal plasma. Safety data have further confirmed the bodyguard function of the placenta. To date the mother is in oncological follow-up as well as the baby in pediatric one. We are currently following another patient, 38 years old, affected by the same pathology as well as treatment. The conception was spontaneous, occurred under treatment and she is now 31 weeks pregnant: for now, there have been no side effect for mom and fetus.

Conclusion These cases, albeit only two, reveals that Alectinib during pregnancy is not necessarily associated with detectable changes in the embrio-fetal development. For the time, fertile patient treated with this new drugs must be recommended for contraception, but in case of desire of motherhood or ongoing pregnancy a multidisciplinary team should comfort the patient in making choices: a well-informed patient can choose consciously.