ALK-positive non-small cell lung cancer (NSCLC) is a distinct molecular subtype of lung cancer characterized by a rearrangement in the Anaplastic Lymphoma Kinase (ALK) gene.
This genetic change, often a fusion with the EML4 gene, creates an “oncogene” that sends continuous signals for cancer cells to grow and divide.
It occurs in approximately 4–5% of all NSCLC cases
Patients are frequently young, fit, and never smokers.
With ALK inhibitors survival is now measured in years and is associated with preserved quality-of-life.
Drug resistance is inevitable and patients eventually succumb to the disease.
There are three generations of ALK tyrosine kinase inhibitors available.
ALK fusions are present in 3-7% of NSCLCs.
Associated with adenocarcinoma histology.
Diagnosis
Identifying ALK status is critical for treatment planning. It is detected through biomarker testing using:
IHC (Immunohistochemistry checking for the abnormal ALK protein.
FISH (Fluorescence In Situ Hybridization): Uses fluorescent probes to visualize gene rearrangements.
NGS (Next-Generation Sequencing): A comprehensive test that can identify ALK and other mutations simultaneously.
This subtype has a high risk of spreading to the brain, with about 30% of patients having brain metastases at diagnosis, and up to 3/4 of patients throughout the disease course.
It is not Inherited is an acquired (somatic) mutation, meaning it is not passed down through families.
Treatment Options The standard of care involves Targeted Therapy with ALK inhibitors, also known as Tyrosine Kinase Inhibitors (TKIs).
These drugs block the faulty signaling of the ALK protein.
| 1st Gen | Crizotinib (Xalkori)-The first approved ALK TKI.
2nd Gen | Alectinib (Alecensa), Brigatinib (Alunbrig), Ceritinib (Zykadia), Ensartinib (Ensacove)-Better brain penetration and more potent than 1st generation.
3rd Gen | Lorlatinib (Lorbrena) | Specifically designed to cross the blood-brain barrier and overcome resistance mutations.
Recent Approvals & News:
Alectinib (Alecensa): Recently approved as an adjuvant therapy (treatment after surgery) for early-stage ALK+ NSCLC to reduce the risk of recurrence.
Lorlatinib (Lorbrena): Often preferred as a first-line treatment due to its superior long-term control of both systemic and brain disease.
Neladalkib: to treat patients previously treated with other TKIs.
Most patients eventually develop drug resistance, causing the cancer to grow again.
A new biopsy to identify the specific resistance mutation (e.g., G1202R) to choose the next best drug.
Many patients now surviving 7 years or longer with advanced disease.
Current recommended adjuvant treatment for a patient with resected ALK positive. NSCLC is platinum-based combination chemotherapy, however, risk recurrence is high with a five-year recurrence rate or death ranging from 45% for stage 1B disease to 76% prestige III disease.
Five-year survival ranges from 71% per stage IB disease to 36% for stage IIIA disease.
Among patients with resected, ALK positive NSCLC of stage, IB II or IIIA adjuvant alectinib significantly improved disease free survival as compared with platinum-based chemotherapy (ALINA investigators.).
Standard treatment for metastatic ALKpositive NSCLC after progression on ALK TKIs is platinum doublet chemotherapy with pemetrexed for adenocarcinoma histology.
However, continuing the ALK TKI with the platinum pemetrexed prolonged progression free survival and overall survival than platinum/pemetrexate alone.
Molecular therapies with first, second, and third generation ALK inhibitors have improved patient survival measured in years, and preserved quality-of-life.
Drug resistance is presently inevitable and patients with advanced disease eventually succumb.