15 Apr, 2026
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15 Apr, 2026
Your immune system is already built to destroy threats. Cancer survives by outsmarting it.
Tumor cells display a surface protein called "PD-L1" that sends a "do not attack" signal to patrolling immune cells. The immune system stands down. The tumor grows unchallenged.
Immunotherapy interrupts that deception. Rather than introducing toxic drugs, immunotherapy restores the immune system's own capacity to recognize and eliminate cancer. Eligibility is not based on the cancer type alone. It depends on tumor biomarkers: PD-L1 expression, tumor mutational burden (TMB), and microsatellite instability (MSI). Biomarker testing always comes before any treatment decision.
When a T-cell approaches a tumor cell, PD-L1 binds to PD-1 on the T-cell surface. That binding switches the immune cell off. Checkpoint inhibitors physically block this handshake. Once activated, T-cells resume hunting tumor cells actively.
The Cancer Research Institute notes that some patients achieve remission that outlasts the treatment period by years. That kind of durability is rarely seen with chemotherapy.
CAR T-cell therapy works differently. A patient's T-cells are taken out, sent to a lab, and changed to have chimeric antigen receptors (CARs) that attach to tumor markers like CD19 or BCMA. Billions of these re-engineered cells are reinfused. They replicate inside the body and continue working long after the infusion ends.
Common confusion: Immunotherapy and targeted therapy are not the same thing. Targeted therapy blocks a mutation inside the tumor cell. Immunotherapy recruits the immune system to attack it from the outside. Different mechanisms entirely.
| Type | What It Does | Known Agents |
|---|---|---|
| Checkpoint Inhibitors | Block PD-1, PD-L1, or CTLA-4 to reactivate T-cells | Pembrolizumab, Nivolumab, Ipilimumab |
| Monoclonal Antibodies | Attach to tumor surface antigens and flag them for destruction | Rituximab (CD20), Daratumumab (CD38) |
| CAR T-Cell Therapy | Re-engineers patient T-cells with tumor-targeting receptors | CD19+ lymphoma, ALL, BCMA in myeloma |
| Cancer Vaccines | Train the immune system to identify tumor-specific proteins | Sipuleucel-T, therapeutic HPV vaccines |
| Cytokines | Amplify immune cell activity through signalling proteins | IL-2, Interferon-alpha |
| Oncolytic Virus Therapy | Modified viruses burst cancer cells open, releasing antigens | Talimogene laherparepvec (T-VEC) |
| Immunotherapy Type | Purpose (What It's Designed To Do) |
|---|---|
| Checkpoint Inhibitors | Remove immune "brakes," so T-cells can recognize and attack cancer cells |
| Monoclonal Antibodies | Bind to tumor-specific antigens and mark cancer cells for immune destruction |
| CAR T-Cell Therapy | Genetically modify patient T-cells to directly identify and kill cancer cells |
| Cancer Vaccines | Train the immune system to recognize tumor-specific proteins and mount a response |
| Cytokine Therapy | Stimulate and amplify overall immune cell activity against cancer |
| Oncolytic Virus Therapy | Use modified viruses to infect and rupture cancer cells, triggering immune activation |
Good to Know: Immunomodulators such as lenalidomide regulate immune activity broadly and are used extensively in multiple myeloma alongside direct immunotherapy agents.
Tumors with high TMB or MSI-high (dMMR) status tend to produce the strongest responses. Their mutation-dense profiles give immune cells more targets to recognize.
Confirmed treatment indications include:
In summary, a cancer diagnosis alone never confirms immunotherapy eligibility. The tumor's molecular profile does.
Biomarker testing first. A tissue biopsy or liquid biopsy is analyzed for PD-L1 scoring, MSI status, TMB, and relevant antigen expression. No treatment plan moves forward without this data.
tumor board review. Oncologists, pathologists, and genomic specialists review results together before any recommendation is made.
Infusion or oral dosing. Most checkpoint inhibitors are delivered as IV infusions every 2 to 6 weeks. Sessions run 30 to 90 minutes. Patients return home the same day.
Cycle monitoring. Blood panels and clinical review occur at every cycle. Imaging follows at 8 to 12 weeks using iRECIST criteria.
One thing worth knowing: some patients experience pseudoprogression, where tumors appear larger on scans before they begin shrinking. Imaging is always interpreted alongside clinical markers, not in isolation.
Forget the chemotherapy image. Hair does not fall out overnight. Nausea is not the defining experience.
With immunotherapy, the body's amplified immune response can turn on healthy tissues. A skin rash appears in roughly 30 to 40% of patients. Immune-mediated colitis feels like persistent cramping with loose stools. Thyroid dysfunction shows up quietly: either an unexplained exhaustion or an edgy restlessness that feels out of place. Pneumonitis brings a dry cough or breathlessness that does not resolve on its own.
Severe grade 3 to 4 irAEs affect around 10 to 15% of patients on single-agent checkpoint inhibitors, per JITC data. When that occurs, immunotherapy is paused immediately and high-dose corticosteroids are started. Mild irAEs are managed with close clinical observation.
Late-onset irAEs can emerge weeks or months after the final infusion. Post-treatment surveillance is not optional.
Biosimilar availability in Bangalore, Mumbai, Delhi, and Kolkata can reduce per-cycle costs. Costs vary by hospital and patient profile. Confirm insurance pre-authorization and Ayushman Bharat or CGHS eligibility before the first cycle.
For many patients, the next helpful step is a proper biomarker report and a conversation with a multidisciplinary team that can interpret what the numbers actually mean for their situation.
Immunotherapy has shifted outcomes in cancers that had very few options a decade ago. Durable remission is no longer rare in melanoma or MSI-high colorectal cancer. Blood cancer patients who have exhausted every other option are now responding to CAR T-cell infusions.
HCG Cancer Hospital supports patients through biomarker-guided immunotherapy evaluation, genomic profiling via Triesta Sciences, and structured irAE monitoring throughout the treatment journey.
Disclaimer: This information is intended to educate patients and caregivers. It does not replace professional medical advice. All treatment decisions should be made in consultation with a qualified doctor.
