All subjects will return to the clinical site on Day 7 to assess acute safety after the first injection. After that, subjects in the monthly groups will return to the clinical site for additional APL-2 (or Sham) injections and study procedures every month until Month 12. Subjects in the Every-Other-Month groups will return to the clinical site for additional APL-2 (or Sham) injections and study procedures every two months until Month 12. All subjects will return for follow-up visits on Months 15 and 18 (3 and 6 months after last injection, respectively).