Cognitive and Mood Changes on Lorlatinib

Around month three, the patient’s wife notices he is more irritable. He reports mild difficulty concentrating. Scans are stable, but behaviour has changed, and the person who noticed was not in the clinic.

Written by Katrina Metz, RT·Medically reviewed by Dr. Geoffrey Liu, MD MPH·Last updated

Key Takeaways

  • CNS adverse events include changes in mood, cognition and speech.
  • Most are Grade 1-2, with median onset at 2 to 4 months.
  • Incidence does not increase over time and discontinuation rates are very low.
  • The risk is delayed recognition, not the event itself.
  • CNS changes are often early and reversible with structured intervention.

Table of Contents

Understanding the Pattern

CNS effects are a recognised part of the lorlatinib profile. They span mood, cognition and speech, and most sit at Grade 1 or 2. Median onset is two to four months, and incidence does not increase over time.

Discontinuation rates for CNS events are very low. Most are manageable with structured intervention.

That combination of common, early, mild and reversible means the clinical priority is detection speed rather than severity management.

Key message: CNS changes are often early and reversible.

Why Recognition Is Delayed

Cognitive and mood changes are the adverse events least likely to be volunteered. The patient may not perceive them, or may attribute them to stress, sleep, or the diagnosis itself.

This is why caregiver input matters more here than for any other event in the series. The change is often visible to a spouse or family member before it is visible to the patient or measurable in clinic.

Building a direct question for caregivers into structured follow-up is a low-cost intervention with high yield.

Rapid Interruption and Safe Re-initiation

The management principle is speed of response rather than magnitude. When CNS symptoms affect function or safety, interrupt early rather than waiting to see whether they settle.

Re-initiation happens at a modified dose. Rapid re-escalation should be avoided for CNS toxicity specifically. See Video 8: Dosing and Dose Modification.

Frequently Asked Questions

What is the PMMR framework?
PMMR stands for Prepare, Monitor, Manage, Reassess. It is a practical framework for managing lorlatinib's adverse effects, developed by Dr. Geoffrey Liu and colleagues and published in Lung Cancer (2024). Prepare means setting expectations with the patient before the first dose. Monitor combines laboratory values and patient report. Manage means responding in proportion to functional impact. Reassess means confirming the intervention worked and checking for new issues. It is a continuous cycle rather than a one-time checklist. Related: Video 1: PMMR and the Foundations of ALK+ Patient Management
What is the recommended starting dose of lorlatinib?
The recommended starting dose is 100 mg daily. Clinical guidance is to begin at full dose unless contraindicated. Early adverse events are common but often manageable, and starting at full dose maximises initial disease control. Related: Video 8: Dosing and Dose Modification Strategies
Does reducing the dose of lorlatinib compromise its effectiveness?
No. Dose reduction in the early weeks did not compromise progression-free survival or intracranial outcomes. Structured reductions go from 100 mg to 75 mg daily, and to 50 mg daily if a second reduction is required. Dose reduction is part of long-term management, not treatment failure, and this should be stated explicitly to patients. Related: Video 8: Dosing and Dose Modification Strategies
How often should lipids be monitored on lorlatinib?
A baseline lipid profile, a recheck at one month, two months and then every 3 months. Onset of lipid changes is approximately 15 days, which is why the two-week check matters. Trend over time is more informative than any single value. Related: Video 7: Hyperlipidemia and Metabolic Effects
Which statins are preferred in patients on lorlatinib?
Pitavastatin, pravastatin and rosuvastatin are preferred, selected on the basis of their drug interaction profile. If control is inadequate, ezetimibe can be added, and a fibrate or fish oil for triglycerides. Diet alone is rarely sufficient, and dose reduction of lorlatinib is rarely required for lipids alone. Related: Video 7: Hyperlipidemia and Metabolic Effects
How common are adverse events on lorlatinib?
Most adverse events are Grade 1 or 2. Hypercholesterolemia occurs in approximately 70 to 75 percent of patients and hypertriglyceridemia in approximately 60 to 65 percent. Weight gain occurred in approximately 44 percent of patients in long-term CROWN follow-up. Peripheral edema, peripheral neuropathy and CNS effects are also common, with median onset of two to four months. For most events, incidence does not increase over time. These are CROWN long-term follow-up figures rather than a global average. Related: Video 2: Weight Gain · Video 3: Peripheral Edema · Video 4: Peripheral Neuropathy
What CNS side effects can occur with lorlatinib, and are they reversible?
CNS adverse events include changes in mood, cognition and speech. Most are Grade 1 to 2, with median onset at two to four months, and discontinuation rates are very low. These changes are often early and reversible with structured intervention. The main clinical risk is delayed recognition rather than the severity of the event, which is why caregiver input is valuable. Changes are frequently noticed by a family member before the patient reports them. Related: Video 5: Cognitive and Mood Changes
Should therapy be switched if there is isolated CNS progression?
Not automatically. If progression is intracranial only, confirm the imaging, assess symptom burden, consider local therapy, and continue CNS-active systemic therapy where appropriate. Time to intracranial progression is significantly prolonged with lorlatinib, and dose reduction does not compromise intracranial efficacy. Therapy should not be switched reflexively for limited CNS progression. Related: Video 9: Sequencing After Progression · Video 6: Brain Metastasis
When should a patient on lorlatinib be referred to a specialist?
Refer when function, safety, or disease control is at risk. Neurology or psychiatry for functional cognitive impairment, behavioral instability, safety concerns, or persistent CNS toxicity despite dose adjustment. Cardiology or a lipid clinic when lipids remain uncontrolled despite maximal statin therapy, or where there is statin intolerance or complex cardiovascular risk. Radiation oncology or a tertiary centre for isolated CNS progression or symptomatic lesions. Central oncologic oversight should be maintained throughout. Related: Video 11: When to Refer to a Specialist
How often should patients on lorlatinib be followed up?
Biweekly during the first month, monthly for three months, and every three months thereafter. After any treatment interruption, return to biweekly reassessment. A standardised adverse event checklist at each visit, screening for weight change, edema, neuropathy, and mood or cognition, improves detection compared with open-ended questioning. Related: Video 10: Clinical Tools for Monitoring and Follow-Up

This content is intended for healthcare professional education and reflects clinical guidance current at the time of publication. It is not a substitute for the product monograph, institutional protocols, or individual clinical judgement.

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This video is one of twelve in Managing Lorlatinib in ALK+ NSCLC, developed with Dr. Geoffrey Liu and the CARMA-BROS network at Princess Margaret Cancer Centre.

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About this article

Written by Katrina Metz, RT, respiratory therapist and medical writer at RESPIPLUS. Medically reviewed by Dr. Geoffrey Liu, MD MPH, Senior Scientist at Princess Margaret Cancer Centre and a leading Canadian expert in ALK-positive NSCLC management.

About this project
This series was supported by Pfizer and developed independently by RESPIPLUS with the CARMA-BROS network. Scientific Committee: Dr. Geoffrey Liu (Princess Margaret), Maria Sedeno (RESPIPLUS), Emily Horvat (RESPIPLUS), Katrina Metz (RESPIPLUS), Christopher Deutschman (CARMA-BROS), Faisal Al Agha (CARMA-BROS). All materials are free and permanently hosted on chroniclungdiseases.com.

Published August 4, 2026. Last reviewed . For educational purposes only. Not a substitute for medical advice.