Carboplatin, Cyclophosphamide, Melphalan, and Thiotepa

The combination of carboplatin, cyclophosphamide, melphalan, and thiotepa represents a high-dose chemotherapy regimen that has been studied in clinical trials for metastatic breast cancer. This combination is typically administered with autologous bone marrow or peripheral blood progenitor cell support to help patients recover from the myelosuppressive effects of these high-dose alkylating agents. ## Clinical Applications This combination has been primarily investigated in phase II clinical trials for patients with metastatic breast cancer who have shown at least a partial response to standard-dose chemotherapy. The regimen is typically administered as sequential high-dose cycles: - Melphalan (140-180 mg/m²) with peripheral blood progenitor cell support - Followed by a combination of cyclophosphamide (6000 mg/m²), thiotepa (500 mg/m²), and carboplatin (800 mg/m²) administered over 4 days by continuous infusion[1][3][4] ## Efficacy and Outcomes Clinical trials have shown that this high-dose combination can produce significant response rates in metastatic breast cancer patients. In one study, the overall response rate was 87%, with 30% of patients remaining progression-free with a median follow-up of 31 months[1]. Another study reported that 34% of patients remained progression-free a median of 16 months after treatment[3]. The most durable responses were observed in patients who achieved a complete response. Some patients who achieved complete responses remained progression-free for extended periods (17-31 months after transplantation)[4]. ## Toxicity Profile The regimen is associated with significant toxicity, including: - Reversible sensory polyneuropathy (particularly following paclitaxel when included in the sequence) - Fever and mucositis requiring hospitalization - Liver toxicity, including venoocclusive disease - A toxic death rate of approximately 3-5%[1][3] Due to liver toxicity concerns, researchers found that increasing the interval between melphalan administration and the CTCb (cyclophosphamide, thiotepa, carboplatin) combination from 24 to 35 days reduced complications[3]. This high-dose chemotherapy approach with stem cell support represents an intensive treatment strategy that was investigated primarily in the 1990s and early 2000s for patients with advanced breast cancer who had responded to conventional chemotherapy but needed additional treatment to maintain or improve their response.