IMMUNE CHECKPOINT
INHIBITORS: PD-1, PD-L1, CTLA-4
Checkpoint inhibitors remove the brakes cancer puts on the immune system β enabling T cells to recognise and destroy tumours. Understanding which biomarkers predict response is key.
How Checkpoint Inhibitors Work
Cancer cells exploit PD-1, PD-L1, and CTLA-4 proteins to avoid being killed by T cells. Checkpoint inhibitors block these proteins, restoring T-cell ability to attack cancer.
PD-1 and PD-L1 Pathway
PD-1 on T cells binds PD-L1 on tumour cells β sending an "off" signal. Anti-PD-1 (pembrolizumab, nivolumab) or anti-PD-L1 (atezolizumab, durvalumab) drugs block this interaction, restoring T-cell activity.
CTLA-4 Pathway
CTLA-4 suppresses T-cell responses after activation. Anti-CTLA-4 (ipilimumab) removes this suppression. Often combined with anti-PD-1 for greater effect in melanoma and other cancers.
Approved Checkpoint Inhibitors
| Drug | Target | Approved Cancers (Selected) |
|---|---|---|
| Pembrolizumab (Keytruda) | PD-1 | Melanoma, NSCLC, HNSCC, MSI-H, cervical, gastric, TMB-H |
| Nivolumab (Opdivo) | PD-1 | Melanoma, NSCLC, RCC, HNSCC, gastric, hepatocellular |
| Atezolizumab (Tecentriq) | PD-L1 | NSCLC, TNBC, urothelial, hepatocellular |
| Durvalumab (Imfinzi) | PD-L1 | NSCLC stage III, SCLC, biliary tract |
| Ipilimumab (Yervoy) | CTLA-4 | Melanoma, RCC, NSCLC (combo), MSI-H CRC |
Frequently Asked Questions
About Checkpoint Inhibitors
Do checkpoint inhibitors work for all cancers?
No. They work best in immunogenic cancers β MSI-H, TMB-high, or high PD-L1. MSS colorectal and most pancreatic cancers respond poorly. Confirm your cancer type and biomarker profile with your oncologist before treatment.
Are checkpoint inhibitors cheaper in China or India?
Yes. Chinese biosimilar PD-1 inhibitors (sintilimab, tislelizumab, camrelizumab) cost $3,000β10,000/year versus $100,000+ for pembrolizumab/nivolumab in Western markets. CancerFax helps patients access these through appropriate care pathways at Chinese centres.
Related Resources
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination β travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.
Questions About Checkpoint Inhibitor Eligibility?
CancerFax reviews your biomarkers and cancer type to confirm whether checkpoint inhibitors are appropriate and identifies affordable access options.
For patient education only. Consult a qualified oncologist before treatment decisions.