Phase 1:~Evaluate the safety and tolerability of MEDI-538 at doses of 5, 10, 15, 30, 45, or 60 mg/m2/24h by continuous IV infusion for 4 weeks in adult patients with CLL who have measurable disease following previous therapy for CLL. Patients with measurable disease include patients who demonstrated PD, SD, or PR following previous therapy for CLL; and~Determine the maximum tolerated dose (MTD) of MEDI-538 administered by continuous IV infusion for 4 weeks in this patient population;~Describe the pharmacokinetics (PK) of MEDI-538~Describe the immunogenicity (IM) of MEDI-538~Determine the overall response, which is defined as follows: (1) conversion from PD/SD to PR/nPR/CR or conversion from PR to nPR/CR using standard NCI-WG criteria; or (2) conversion from MRD positivity to MRD negativity using 4-color flow cytometry; and~Describe any antitumor activity (ie, time to response and duration of response) of MEDI-538 in this patient population.~Phase 2:~Determine the overall response in adult patients with CLL who have residual disease following previous therapy for CLL.~Describe the safety of MEDI-538~Describe the PK of MEDI-538~Describe the IM of MEDI-538~Determine the time to MRD relapse~Determine the antitumor activity (ie, time to response, duration of response, and time to progression [TTP]) of MEDI-538 in this patient population.
Phase 1:~Evaluate the safety and tolerability of MEDI-538 given by escalated doses with continuous IV infusion for 4 weeks in adult patients with CLL.~Determine the maximum tolerated dose (MTD) of MEDI-538 administered by continuous IV infusion for 4 weeks in this patient population~Describe the pharmacokinetics (PK) of MEDI-538~Describe the immunogenicity (IM) of MEDI-538~Determine the overall response, which is defined as follows: (1) conversion from PD/SD to PR/nPR/CR or conversion from PR to nPR/CR using standard NCI-WG criteria; or (2) conversion from MRD positivity to MRD negativity using 4-color flow cytometry; and~Describe any antitumor activity (ie, time to response and duration of response) of MEDI-538 in this patient population.~Phase 2:~To determine the overall response in adult patients with CLL who have residual disease following previous therapy for CLL.~Describe the safety,PK,and IM of MEDI-538~Determine the time to MRD relapse~Determine the antitumor activity (ie, time to response, duration of response,and time to progression [TTP])of MEDI-538 in this patient population.