This is an investigator-initiated, single-center clinical trial evaluating the efficacy and safety of ALK inhibitors in patients with locally advanced or metastatic bone cancer harboring truncated ALK (ALKATI) alterations. Eligible patients must have disease progression after standard therapy or no suitable standard treatment options.

Participants will receive either crizotinib (Xalkori®) or alectinib (Alecensa®), with treatment selection determined by the study investigators. The study aims to assess antitumor activity, safety, and clinical outcomes in this rare molecular subtype of bone cancer.

This is an investigator-initiated, single-center clinical trial evaluating the safety and efficacy of ALK inhibitors in patients with locally advanced or metastatic bone cancer harboring truncated ALK (ALKATI) alterations. This molecular subtype has been associated with poor prognosis and limited response to conventional therapies.

Preclinical studies conducted by the study team have demonstrated that ALK inhibitors, including crizotinib (Xalkori®) and alectinib (Alecensa®), exhibit antitumor activity against bone cancer cells with truncated ALK expression. Based on these findings, this study aims to explore their therapeutic potential in a clinical setting.

Eligible patients are those who have experienced disease progression after standard treatment or have no appropriate standard treatment options available. Participants will receive oral ALK inhibitor therapy, with treatment selection and dose adjustments determined by the investigators based on clinical response and tolerability.

The primary objective of this study is to evaluate antitumor activity in this rare molecular subset of bone cancer. Secondary objectives include safety, tolerability, and clinical outcomes.

Inclusion Criteria:

• Age ≥ 20 years.
• Patients with locally advanced or metastatic solid tumors harboring deficiency or alteration of anaplastic lymphoma kinase (ALK) tyrosine kinase.
• Disease progression during or within 6 months after completion of standard therapy, or no appropriate standard treatment available.
• At least one measurable lesion according to applicable response evaluation criteria.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
• Estimated life expectancy of at least 8 weeks.

Exclusion Criteria:

• Known hypersensitivity to crizotinib or alectinib.
• Current or prior use of ALK inhibitors.
• Current use of tyrosine kinase inhibitors.
• Receipt of radiotherapy within 2 weeks prior to study entry. Palliative radiotherapy to non-target lesions is permitted.
• History of other malignancies, except for osteosarcoma or chondrosarcoma, unless the patient has been disease-free for at least 2 years. Exceptions include adequately treated basal cell carcinoma, squamous cell carcinoma of the skin, or carcinoma in situ of the cervix.
• Liver cirrhosis with a Child-Pugh score ≥ 8.
• Uncorrectable electrolyte abnormalities.
• Presence of brain metastases.
• Active acute infection.
• Significant unresolved toxicity from prior therapy.
• Comorbid conditions that may interfere with study participation, including but not limited to uncontrolled diabetes mellitus, autoimmune diseases, or any condition that, in the investigator's judgment, renders the patient unsuitable for the study.
• Concurrent malignancy, unless it is adequately treated carcinoma in situ or basal cell carcinoma, or a malignancy that has been treated and has remained recurrence-free for at least 3 years.
• Pregnant or breastfeeding women.
• Patients with psychiatric disorders that may impair compliance with study requirements.
• Current use of strong inducers or inhibitors of CYP3A enzymes, or use of other investigational or non-approved drugs.