Subjects who completed participation in PAL 001 will receive priority to participate in PAL 002. rAvPAL PEG naïve subjects will be enrolled to fill any dose cohort vacancies resulting from subjects who did not complete PAL 001 or who chose not to continue into PAL 002. In addition, if the number of dose cohorts determined in PAL 001 is less than 7, additional naïve subjects may be added to the existing dose cohorts to provide a total of approximately 35 subjects entering Part 1 of PAL 002. Furthermore, if serial dosing of cohorts in Part 1 of PAL 002 is stopped, additional subjects (either naïve subjects or PAL 001 subjects) may be added to the existing cohorts so that total study enrollment is approximately 35 subjects. In any of these cases, additional subjects will be enrolled sequentially from lowest to highest dose cohort.