Paclitaxel Once Weekly (Wp) Combined With Fixed Dose Of Oral Metronomic Cyclophosphamide (Omc): A Dose-Escalating Phase I Trial.

e14015 Background: OMC, as continuous administration of low doses of chemotherapy acts as direct cytotoxic as well as antiangiogenetic agent. wP also induces antiangiogenic effects in mouse models. The aims of this trial were to determine the recommended Phase 2 dose (RP2D) of wP given in combination with OMC, and estimate activity and safety of the combination. Methods: Methods This is a single-center, phase 1 trial. Patients (pts) > 18 years with refractory metastatic cancers were eligible if no standard curative measures existed. Paclitaxel was administered IV weekly (D1, D8, D15; D1 = D28) in combination with a fixed dose of OMC (50mg x2/day). A 3+3 design was used for Dose-Escalation of wP (40 mg/m² to 75 mg/m²), followed by an expansion cohort at RP2D. The primary endpoint was the dose-limiting toxicity (DLT), defined as grade > 3 non-hematological or grade 4 hematological toxicity (NCI-CTCAE v4.0) occurring in the first 28 days, or any toxicity leading to a dose reduction. Results: 28 pts (18 in dose-escalation phase and 10 in expansion cohort) were included between May 2011 and December 2013. The sex ratio was 2:1, the median age was 54.5 (range, 26-67); the most common primary tumors were colorectal cancers (n = 9), sarcomas (n = 4), Head & Neck (n = 3). 16/18 pts enrolled in the dose-escalation phase were evaluable for DLT. DLT occurred in 0/3, 1/6 (neuropathy), 0/3 and 2/4 pts (hematological toxicity) at dose 40, 60, 70 and 75 mg/m² of wP, respectively. The RP2D of wP was 70 mg/m2; 1/10 pts in the expansion phase had an hematological DLT. At RP2D (n = 14), the maximal grade of adverse events (AE), regardless of causality, was Gr2 in 3 pts, Gr3 in 7 pts, Gr4 in 3 pts and Gr5 in 1 pt; the maximal grade of treatment-related AE was Gr1 in 1 pt, Gr2 in 8 pts, Gr3 in 3 pts and Gr4 in 1 pt (no AE in 1 pt). At RP2D, the median PFS was 2.8 mo and Growth Modulation index was ≥1.33 in 4/14 pts (29%). There was 1 objective response (1/14; 7%): 1 pt with lung adenocarcinoma achieved a partial response. Conclusions: The combination of OMC and wP resulted in an acceptable safety profile. Further evaluation of this combination with wP at 70mg/m² could be warranted in a phase 2 trial. Clinical trial information: NCT01374620.