BioMarin Pharmaceuticals (NASDAQ:BMRN) keeps chugging along, pushing its orphan drug pipeline forward. Yesterday, the biotech announced data from two trials, giving the company confidence to move two programs to the next step.

First, phase 2 data for PEG-PAL, which treats phenylketonuria, looked good. The drug reduced blood Phe levels to 68% of pre-treatment baseline levels in patients treated for one year. And all those patients had Phe measurements below 600 umol/L, substantially below the 900 umol/L recommended by the National Institutes of Health.

BioMarin already has an approved drug to treat phenylketonuria, but Kuvan isn't nearly as good. Only 20% of patients reached their Phe target and the overall reduction was only 29%. PEG-PAL may cannibalize some of the Kuvan sales, but since it's much more effective, PEG-PAL will likely capture patients who would otherwise try to treat their phenylketonuria with a low Phe diet.

BioMarin plans to move PEG-PAL into phase 3 in the second quarter of 2013 after it meets with the Food and Drug Administration to get its input on the trial design.

The second trial was of the early, phase 1 variety, testing BMN-111 for achondroplasia, the most common form of dwarfism. The drug is designed to indirectly inhibit fibroblast growth factor receptor 3, which is overactive in patients with achondroplasia.

This was only a phase 1 trial in healthy patients to determine the proper dose to move into phase 2 development, but at least no safety issues were identified and BioMarin can work on designing the phase 2 proof-of-concept trial.

Moving these two drugs along is important for the overall growth of the company. BioMarin, Alexion Pharmaceutical (NASDAQ:ALXN), ViroPharma (UNKNOWN:VPHM.DL), and Shire (NASDAQ:SHPG) have made big bucks selling drugs for orphan diseases that affect relatively few individuals. But it's easy to saturate the market when there isn't any competition, leaving new products as the obvious driving force for higher revenue.