Study Design

The study design consists of a 4- to 16-week dose escalation stage, a 12- to 28-week efficacy evaluation and maintenance stage at doses that maintain hematocrit levels in the desired range of  less than 45 percent, and randomized and blinded withdrawal stage for up to 12-weeks.

The study has an open-label extension for up to one year. Dosing is provided by self-administered subcutaneous injection, usually at weekly intervals.

The study protocol allows for accommodations during the COVID-19 pandemic, e.g., allowing for local delivery of study medication and alternative study visits (phone or virtual visits), as needed.

The objectives of the study are to assess:

  • Efficacy, as the proportion of subjects that do not require phlebotomy
  • Safety, as assessed by participants experiencing treatment-related adverse events
  • Symptom burden
Clinically Effective Dose Finding Phase
4 to 16 Weeks
Efficacy Evaluation Phase
Dose ±
12 to 24 Weeks
Randomized Withdrawal Phase
Fixed Active/
placebo dose
Up to 12 Weeks
Open Label Extension Phase
Dose ±
Up To 52 Weeks