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Didemnin B in metastatic malignant melanoma: a phase II trial of the Southwest Oncology Group
V K Sondak1, K J Kopecky, P Y Liu
1University of Michigan Medical Center, Ann Arbor 48109.
Abstract:
Didemnin B is a cyclic peptide isolated from the marine tunicate Trididemnin cyanophorum. It is a known potent inhibitor of RNA, DNA and protein synthesis, with activity against the murine B16 melanoma. Fourteen patients with disseminated malignant melanoma were evaluated in a Southwest Oncology Group phase II trial of didemnin B at 4.2 mg/m2 by 30 min i.v. infusion every 28 days (SWOG-8754). Only patients with no prior chemotherapy were eligible; prior radiation therapy, surgery and at most one prior biologic regimen were allowed. Patients with brain metastasis were eligible only if the disease in the brain had been treated and controlled. All patients had to have normal renal and hepatic function and adequate granulocyte and platelet counts, a performance status of 0-2, and bidimensionally measurable disease. Fourteen patients were entered on the study; five received one and nine received two courses of didemnin B. No responses were noted among the 11 patients evaluable for response. Five patients developed unusual but reversible hypersensitivity reactions during the second course of therapy. Other toxicity in this trial was nausea and vomiting and diarrhea, none of severity greater than grade 3. Given the lack of antitumor efficacy and the unusual toxicity, further evaluation of didemnin B in this dose and schedule in malignant melanoma is not warranted.
Insights
Didemnin B, a marine cyclic peptide, showed no antitumor efficacy in a phase II trial for malignant melanoma. The drug also presented unusual toxicity, warranting no further evaluation at this dose and schedule.
Area of Science:
- Marine natural products
- Cancer therapeutics
- Pharmacology
Background:
- Didemnin B is a cyclic peptide from marine tunicates with known cytotoxic properties.
- It inhibits RNA, DNA, and protein synthesis, showing activity against murine melanoma models.
Purpose of the Study:
- To evaluate the efficacy and toxicity of Didemnin B in patients with disseminated malignant melanoma.
- To assess the safety and tolerability of Didemnin B in a phase II clinical trial setting.
Main Methods:
- A Southwest Oncology Group phase II trial (SWOG-8754) enrolled 14 patients with malignant melanoma.
- Didemnin B was administered intravenously at 4.2 mg/m2 every 28 days.
- Eligibility criteria included no prior chemotherapy and measurable disease.
Main Results:
- No objective responses were observed in the 11 evaluable patients.
- Five patients experienced reversible hypersensitivity reactions during the second course.
- Common toxicities included nausea, vomiting, and diarrhea (grade 3 or less).
Conclusions:
- Didemnin B demonstrated a lack of antitumor efficacy in this patient population.
- The observed unusual toxicity profile suggests that further investigation of Didemnin B at this dose and schedule for malignant melanoma is not recommended.
