Inclusion Criteria:

          -  Currently enrolled and on pexidartinib treatment in one of the following studies:
             Study PLX108-10 (ENLIVEN), Study PLX108-01, Study PL3397-A-A103 or Study
             PL3397-A-U126.

          -  Willing and able to complete the PROMIS Physical Function Scale and EQ-5D-5L
             throughout the study.

          -  Willing and able to provide written informed consent prior to any study-related
             procedures and to comply with all study requirements.

          -  Females of reproductive potential must have a negative urine pregnancy test at
             Screening/Baseline (to be confirmed by a serum pregnancy test taken on the last
             treatment visit of their prior study). They are advised to use an effective,
             non-hormonal method of contraception during treatment with pexidartinib and for 1
             month after the last dose. Males with female partners of reproductive potential should
             be advised to use an effective method of contraception during treatment with
             pexidartinib and for 1 month after the last dose. Female partners of male patients
             should concurrently use effective contraceptive methods (hormonal or non-hormonal).

        Note: A female is considered of reproductive potential following menarche and until
        becoming postmenopausal (no menstrual period for a minimum of 12 months) unless permanently
        sterile (undergone a hysterectomy, bilateral salpingectomy or bilateral oophorectomy) with
        a confirmed by follicle stimulating hormone (FSH) test level >40 mIU/mL.

          -  Male participants must not freeze or donate sperm starting at Screening and throughout
             the study period, and for at least 5 half-lives or 1 month after the final study drug
             administration, whichever is longer. Female participants must not donate, or retrieve
             for their own use, ova from the time of Screening and throughout the study treatment
             period, and for at least 1 month or 5 half-lives after the final study drug
             administration, whichever is longer.

        Exclusion Criteria:

          -  Participant has a clinically significant abnormality identified by the Investigator at
             Screening on physical examination, laboratory tests, or electrocardiogram (ECG) which,
             in the judgement of the Investigator, would preclude the participant's safe completion
             of the study.

          -  Exposure to another investigational drug or current participation in other therapeutic
             investigational procedures, besides pexidartinib studies, within 1 month prior to
             start of study treatment. Any known contraindication to treatment with, including
             hypersensitivity to, the study drug(s) or excipients in pexidartinib.