The US FDA has recently approved atezolizumab, an anti-PD-L1 immune checkpoint inhibitor, for the treatment of adults and children 2 years and older with that inoperable or metastatic alveolar soft part sarcoma. This makes it the “first approval of a treatment” for this condition and the “first time that it has been approved for children”.

Alveolar soft part sarcoma is a rare malignant tumor that arises from different types of soft tissue like fat, muscle or nerves. It occurs mostly in adolescents and young adults.

Atezolizumab is already FDA approved for non-small cell lung cancer (NSCLC), small cell lung cancer, hepatocellular carcinoma and melanoma.

The approval was granted on the basis of findings of a non-randomized phase 2 trial (NCT03141684) of 49 patients, both adults and children, which was supported by the National Cancer Institute (NCI). An infusion of atezolizumab was administered once every 21 days in doses of 1200 mg IV for adults and 15 mg/kg for children until disease progression or intolerance to treatment was observed. Tumor shrinkage was observed in around one-third of patients; the duration of response was ≥6 months in 67% patients, while in 42%, the response persisted for at least a year or more.

Formulation: 840 mg/14 mL (60 mg/mL) and 1200 mg/20 mL (60 mg/mL) solution in a single-dose vial

Dose & Administration

• Adults: 840 mg every 2 weeks, 1200 mg every 3 weeks, or 1680 mg x 4 weeks
• Children: 15 mg/kg (max 1200 mg) x 3 weeks

The drug is administered until the disease advances or unacceptable toxicity occurs.

Adverse effects: Fatigue/asthenia, decreased appetite, nausea, cough, and dyspnea (administered alone)

Warning and precautions: Immune-mediated or Infusion-related reactions may occur; liver enzymes, creatinine, and thyroid function during treatment should be regularly monitored. Use with caution in patients who have received allogeneic hematopoietic stem cell transplantation (HSCT). Fetal toxicity may occur; hence, women of reproductive age should be advised to use effective contraception.

Sources

1. NIH News release, Dec. 28, 2022. Available at: https://www.nih.gov/news-events/news-releases/nih-clinical-trial-leads-atezolizumab-approval-advanced-alveolar-soft-part-sarcoma. Accessed on Jan. 3, 2023.
2. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-approval-atezolizumab-alveolar-soft-part-sarcoma, Dec. 9, 2022. Accessed on Jan. 3, 2023.
3. Tecentriq Prescribing information. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/761034s047lbl.pdf. Accessed on Jan. 3, 2023.