A minimum interval of 28 days will be observed between dosing the first and second patient and 7 days between dosing subsequent patients in a given cohort in order to assess the safety and tolerability of CTX DP at that dose. A further 3 patients may be added to any cohort (to a maximum of 18 of total treated patients) at the discretion of the Data Safety Monitoring Board (DSMB) if required to further clarify the safety profile). A minimum interval of 28 days will be observed between dosing the first and second patient and 7 days between dosing subsequent patients in a given cohort in order to assess the safety and tolerability of CTX DP at that dose.