The investigators plan to understand a comprehensive molecular profiling via the plasma, with the primary aim of using this form on analysis to guide subsequent treatment selection. This study will provide a better understanding of ALK resistance in the treatment of Asian lung cancers and allow for improved clinical outcomes by 'matching' the secondary mutations to an ALK inhibitor which would allow for the greatest coverage ultimately leading to lasting duration of response.

Inclusion Criteria:

• Patients with advanced ALK fusion oncogene positive lung adenocarcinoma that have progressed after 1-2 ALK inhibitors, with at least one prior line of 2nd generation ALKi (i.e. Ceritinib, Alectinib, Brigatinib or Ensartinib)

• The availability of sufficient plasma

• Age ≥ 21 years

• WHO performance status ≤ 2

• Life expectancy of ≥ 21 weeks

• Patients should have adequate organ function for potential consideration into clinical trials (routine blood tests are valid within 14 days before enrollment):

  1. Adequate bone marrow function as shown by: ANC ≥ 1.0x10^9/L, Platelets ≥ 75x10^9/L, Hb ≥ 7.5 g/dL
  2. Alanine aminotransferase (ALT) and aspirate aminotransferase (AST) normal range (or ≤ 3.0xULN if liver metastases are present)

• Willing to provide signed informed consent

• Patients whom do not fulfill the above criteria may be discussed on a case-by-case basis within the study team, for potential enrolment

Exclusion Criteria:

• Received more than 2 prior ALK inhibitors (ALKi)
• Symptomatic or uncontrolled brain metastases requiring concurrent treatment inclusive but not limited to surgery and radiation. Stable/ tailing doses of corticosteroids is permitted

Two cohorts will be enrolled, the first cohort will consist of patients that have received prior 2nd generation ALKi only, and the second cohort with patients that have received prior 1st and 2nd generation ALKi.