Labetuzumab Govitecan in Heavily Pretreated Patients With Metastatic Colorectal Cancer

Key Points

  • Tumor reduction and reduction in plasma carcinoembryonic antigen level were observed in 38% of patients with heavily pretreated metastatic colorectal cancer treated with labetuzumab govitecan.
  • Stable disease was observed in approximately half of the patients.

As reported by Dotan et al in the Journal of Clinical Oncology, the antibody-drug conjugate labetuzumab govitecan showed antitumor activity in a phase I/II trial in patients with heavily pretreated metastatic colorectal cancer who had received prior irinotecan therapy. The agent comprises anti-carcinoembryonic antigen–related cell adhesion molecule 5 (CEACAM5) antibody and the active metabolite of irinotecan (SN-38).

Study Details

In the study, 86 patients with at least 1 prior irinotecan-containing therapy received labetuzumab govitecan once weekly at 8 or 10 mg/kg or two times per week at 4 or 6 mg/kg on weeks 1 and 2 of 3-week cycles. Patients had undergone a median of five prior therapies (range = 1–13).

Outcomes

Overall, 38% of patients exhibited both tumor reduction and reduction in plasma carcinoembryonic antigen level. Partial response was observed in 1 patient, and stable disease was reported in 42 patients. Median progression-free and overall survival were 3.6 and 6.9 months, respectively. The most common grade ≥ 3 adverse events were neutropenia (16%), leukopenia (11%), anemia (9%), and diarrhea (7%). The two once-weekly dose schedules were selected for further study.

The investigators concluded: “Monotherapy with labetuzumab govitecan demonstrated a manageable safety profile and therapeutic activity in heavily pretreated patients with metastatic colorectal cancer, all with prior irinotecan therapy. Further studies of labetuzumab govitecan treatment alone or in combination with other therapies in earlier settings are indicated.”

The study was supported by Immunomedics.

Efrat Dotan, MD, of Fox Chase Cancer Center, is the corresponding author of the Journal of Clinical Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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