A Study Evaluating the Safety, Pharmacokinetics, and Efficacy of Alectinib in Pediatric Participants With ALK Fusion-Positive Solid or CNS Tumors

Inclusion Criteria

   - Histologically confirmed diagnosis of CNS or solid tumors with documented evidence of
   ALK gene fusions as assessed centrally through the use of the investigational F1CDx
   assay or based on pre-existing NGS test results

   - Disease status: prior treatment proven to be ineffective (i.e. relapsed or
   refractory), or for whom there is no satisfactory standard treatment available.
   Disease should be measurable and evaluable as defined by Response Evaluation Criteria
   in Solid Tumors (RECIST) v 1.1, or Response Assessment in Neuro-oncology criteria
   (RANO) +/- bone marrow criteria for primary CNS tumors or International Neuroblastoma
   Response Criteria (INRC)

   - Available tumor tissue for submission to the Sponsor from active disease, obtained
   subsequent to last anti-cancer therapy regiment administered and obtained prior to
   study enrollment, or willingness to undergo a core or excisional biopsy sample
   collection prior to enrollment

   - For participants < 16 years old, Lansky Performance Status >/= 50%

   - For participants >/= 16 years old, Karnofsky Performance Status >/= 50%

   - Adequate bone marrow function as defined by the protocol within at least 28 days prior
   to initiation of study drug

   - Participant and/or caregiver willingness and ability to complete clinical outcome
   assessments throughout the study using either electronic, paper, or interviewer
   methods

   - For females of childbearing potential: agreement to remain abstinent (refrain from
   heterosexual intercourse) or use contraception, and agreement to refrain from donating
   eggs, as defined by the protocol

   - For males who are not surgically sterile: agreement to remain abstinent (refrain from
   heterosexual intercourse) or use contraception, and agreement to refrain from donating
   sperm, as defined by the protocol

Exclusion Criteria

   - Medical history of: prior use of ALK inhibitors; diagnosis of Anaplastic Large Cell
   Lymphoma (ALCL); any gastrointestinal disorder that may affect absorption of oral
   medications, such as mal-absorption syndrome or status post-major bowel resection;
   history of organ transplant; stem cell infusions as defined by the protocol

   - Substance abuse within 12 months prior to screening

   - Familial or personal history of congenital bone disorders, bone metabolism
   alterations, or osteopenia

   - Treatment with investigational therapy 28 days prior to initiation of study drug

   - Liver or kidney disease as defined by the protocol

   - National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE)
   v5.0 grade >/=3 toxicities attributed to any prior therapy such as radiotherapy
   (excluding alopecia), which have not shown improvement and are strictly considered to
   interfere with alectinib

   - Co-administration of anti-cancer therapies other than those administered in this study

   - Active hepatitis B or C virus (HBV, HBC), or known HIV-positivity or AIDS-related
   illness

   - Any clinically significant concomitant disease or condition that could interfere with,
   or for which the treatment might interfere with, the conduct of the study or the
   absorption of oral medications or that would, in the opinion of the Principal
   Investigator, pose an unacceptable risk to the participant in this study

   - Any psychological, familial, sociological, or geographical condition potentially
   hampering compliance with the study protocol requirements and/or follow-up procedures;
   such conditions should be discussed with the participant before trial entry

   - Planned procedure or surgery during the study except as permitted treatment as defined
   by the protocol

   - Infection considered by the investigator to be clinically uncontrolled or of
   unacceptable risk to the participant upon induction of neutropenia, including
   participants who are, or should be, on antimicrobial agents for the treatment as
   active infection

   - Pregnant or breastfeeding, or intending to become pregnant during the study or within
   3 months after the final dose of alectinib