This will be a 3-arm randomized, multicenter, double-masked, placebo-controlled study conducted in 2 stages.
Stage 1 is a safety and efficacy phase of 3 years in duration, during which subjects will be allocated to 1 of 3 study medications.
Stage 2 is a randomized follow-up phase of 1 year in duration, during which subjects will be re-randomized to receive 1 of the 3 study medications, with subjects initially randomized to Vehicle only eligible for randomization to low or high-dose NVK-002.
Treatment arms are:
* NVK-002 low dose concentration
* NVK-002 high dose concentration
* Vehicle (placebo)
