Phase I Trial of CG53135-05 to Prevent Mucositis in Patients Undergoing High-Dose Chemotherapy (HDCT) and Autologous Peripheral Blood Stem Cell Transplantation (PBSCT).

Mucositis is a painful side effect of many transplant conditioning regimens used in HDC and PBSCT. This complication often requires treatment with potent narcotic analgesics and may even require intravenous patient-controlled analgesia (PCA) for adequate pain relief as well as total parenteral nutrition (TPN). Infections in this setting may also result from disruption of the mucosal barrier with subsequent migration of intestinal bacteria into the blood stream. Previous treatments with oral rinses and topical applications of soothing gels have largely been ineffective. Recently, a breakthrough class of drugs in the fibroblast growth factor (FGF) family holds great promise in more effectively ameliorating or even preventing oral mucositis (OM). We report on the results of a Phase I trial with CG53135-05, a novel investigational protein therapeutic (FGF-20) that promotes epithelial and mesenchymal cell proliferation in vitro and has demonstrated activity in animal models. 14 patients (ages 25–75) undergoing HDCT with PBSCT were treated with escalating doses of study drug, including 0.1 mg/kg, 0.2 mg/kg and 0.33 mg/kg (concentrations are determined by the UV method which are equivalent to 0.3, 0.6, and 1 mg/kg by the Bradford method previously used). Conditioning regimens used included melphalan (Mel 200), cyclophosphamide, carmustine and etoposide (CBV), carboplatin and thiotepa (CT), cyclophosphamide, etoposide and carmustine (CEC) and busulfan/cyclophosphamide (targeted BuCy). The primary objective of this phase I trial was to evaluate safety, tolerability and pharmacokinetics of CG53135-05. Patients (pts.) were also scored daily for presence of OM using both the WHO and OMAS (oral mucositis assessment scale) grading scales. 7/14 pts. in this study experienced no OM (including 2 Mel 200 patients), 5 pts. experienced only grade 1 OM. while 2 pts. (both treated with Mel 200) experienced grade 3 OM, and no pts. experienced grade 4 OM. 1 pt. experiencing grade 3 OM required TPN. Only 4 pts. experienced diarrhea that lasted more than 4 days and only 1 pt. had gut mucositis-associated (E. coli) bacteremia. The median day of engraftment (ANC>500/uL) occurred on day 14 (range: day 11–19). Patients tolerated the study drug well with no significant side effects up to a dose of 0.33 mg/kg. At that dose, 2 pts. experienced an infusional reaction consisting of fevers, nausea, and mild hypotension. Pharmacokinetics were measured at all dose levels and will be presented. CG53135-05 is a member of a breakthtrough drug class (FGF family) that was well tolerated in autologous stem cell transplant patients at doses up to 0.33 mg/kg with apparent clinical effects in ameliorating or preventing OM - 12/14 pts, thus, avoided severe (grades 3–4) mucositis following HDCT. A larger Phase II clinical trial is planned.