If you are found to be eligible to take part in this study, you will be assigned to a study group based on when you joined this study. Up to 9 groups of 6 participants will be enrolled in Part 1 of the study, and up to 18 participants will be enrolled in Part 2. If you are enrolled in Part 1, the dose of the study drug you receive will depend on when you joined this study. The first group of participants will receive the lowest dose level of the study drug. Each new group will receive a higher dose of the study drug than the group before it, if no intolerable side effects were seen. This will continue until the highest tolerable dose of the study drug is found. If you are enrolled in Part 2, you will receive the study drug at the highest dose that was tolerated in the Part 1 portion.