Biotherapy & Immunotherapy — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Biotherapy is an umbrella term for treatments that use biological molecules — including monoclonal antibodies, cytokines (interleukins, interferons), vaccines, and cell therapies — to treat cancer, autoimmune diseases, and chronic infections. Immunotherapy is a specific subset of biotherapy that focuses on modifying or restoring the immune system's ability to recognise, target, and destroy cancer cells or pathological immune responses. Modern cancer immunotherapy has revolutionised oncology since the approval of ipilimumab (anti-CTLA-4) in 2011 and nivolumab and pembrolizumab (anti-PD-1 checkpoint inhibitors) from 2014. These agents block inhibitory checkpoints that cancer cells exploit to evade immune surveillance. CAR-T cell therapy — in which a patient's own T-lymphocytes are genetically engineered to recognise cancer antigens — represents the cutting edge of adoptive immunotherapy for haematological malignancies. Medical oncologists, haematologists, and immunologists deliver biotherapy in accredited cancer centres. Biotherapy is an umbrella term for treatments that use biological molecules — including monoclonal antibodies, cytokines, vaccines, and cell therapies — to treat cancer, autoimmune disease, and inflammatory conditions. Immunotherapy is the subset of biotherapy that harnesses or augments the immune system to recognise and destroy cancer cells. The major categories include immune checkpoint inhibitors (anti-PD-1, anti-PD-L1, anti-CTLA-4 antibodies), CAR-T cell therapy (chimeric antigen receptor T-cells), bispecific antibodies, and cancer vaccines. Immunotherapy has revolutionised oncology — checkpoint inhibitors such as pembrolizumab and nivolumab have transformed the prognosis of metastatic melanoma, lung cancer, renal cell carcinoma, and other tumour types, achieving durable remissions in a proportion of patients previously expected to die within months. Biotherapy is delivered by medical oncologists and haematologists in specialised cancer centres. CAR-T therapy, the most complex cellular therapy, is administered only at designated CAR-T-certified centres globally.

Biotherapy and immunotherapy are indicated when tumour biomarker testing identifies specific targets amenable to biological treatment. Checkpoint inhibitor immunotherapy is approved for: melanoma (first-line pembrolizumab for PD-L1-positive tumours), non-small cell lung cancer (pembrolizumab, nivolumab, atezolizumab), urothelial carcinoma, renal cell carcinoma, Hodgkin lymphoma, microsatellite instability-high (MSI-H) colorectal cancer, head and neck squamous cell carcinoma, and hepatocellular carcinoma among others. Biomarker selection by PD-L1 immunohistochemistry (tumour proportion score), tumour mutational burden (TMB), and MSI status guides patient selection. Monoclonal antibodies targeting specific receptors include trastuzumab (HER2-positive breast and gastric cancer), bevacizumab (colorectal and lung cancer via VEGF inhibition), and rituximab (CD20-positive B-cell lymphoma). For autoimmune diseases, biologics such as adalimumab, infliximab, and tocilizumab target TNF-alpha, IL-6, and other inflammatory mediators. CAR-T therapy is indicated for relapsed/refractory B-cell ALL and large B-cell lymphoma.

Before initiating immunotherapy, comprehensive workup includes tumour molecular profiling (NGS panel, PD-L1 IHC, MSI testing), baseline imaging (CT PET scan), organ function tests (liver enzymes, renal function, thyroid function, pulmonary function), and autoimmune disease screening. Checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab, durvalumab, ipilimumab) are administered as intravenous infusions every 2–6 weeks in a day oncology unit. Infusion duration is typically 30–60 minutes. Monoclonal antibodies (trastuzumab, bevacizumab, rituximab) are infused over 30–90 minutes, often in combination with chemotherapy cycles. Subcutaneous formulations are increasingly available — trastuzumab SC and rituximab SC reduce administration time to 5–7 minutes and can be given in community settings. Small molecule TKI biologics (imatinib, erlotinib, osimertinib) are taken as once-daily oral tablets at home. CAR-T cell therapy requires a separate lymphodepletion conditioning course before infusion, followed by inpatient monitoring for cytokine release syndrome (CRS). Treatment response is assessed by imaging every 8–12 weeks. Before initiating immunotherapy, comprehensive workup includes tumour molecular profiling (next-generation sequencing panel, PD-L1 immunohistochemistry, microsatellite instability testing), baseline imaging (CT PET scan), organ function tests (liver enzymes, renal function, thyroid function, cortisol), and autoimmune disease history to establish baseline and predict immune-related adverse events. Checkpoint inhibitors are administered as intravenous infusions every 2, 3, or 6 weeks depending on the drug and regimen. Each infusion takes 30–60 minutes and is preceded by vital sign assessment and blood tests. CAR-T cell therapy requires leukapheresis to harvest the patient's T-cells, which are then engineered at a manufacturing facility over 2–4 weeks before reinfusion. Patients require hospitalisation for a minimum of 7–14 days post-CAR-T infusion for monitoring of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Cytokine therapies such as interleukin-2 (IL-2) are administered in intensive care settings due to severe systemic inflammatory responses.

Immunotherapy has transformed cancer outcomes in ways unachievable with chemotherapy. Checkpoint inhibitors produce durable, long-lasting responses in 20–40% of eligible patients — with some patients achieving complete remission lasting 5 or more years in melanoma and lung cancer. Pembrolizumab has improved 5-year overall survival in PD-L1-high non-small cell lung cancer from approximately 10% (chemotherapy) to 35%. In melanoma, the combination of nivolumab and ipilimumab has produced 5-year survival rates of 52% compared to under 10% with chemotherapy for metastatic disease. Unlike chemotherapy, which requires hospital admission and causes severe side effects, immunotherapy is delivered in a day unit and patients can maintain near-normal quality of life during treatment. Subcutaneous biologic formulations further improve convenience. For autoimmune disease, TNF-alpha inhibitors (adalimumab, infliximab) achieve remission in 40–60% of patients with rheumatoid arthritis refractory to methotrexate. CAR-T therapy achieves complete remission rates of 70–85% in relapsed ALL and 50–60% in diffuse large B-cell lymphoma.

Immune-related adverse events (irAEs) are the signature toxicity of checkpoint inhibitor immunotherapy, resulting from excessive immune activation affecting normal organs. Common irAEs include dermatitis (30–40%), hypothyroidism (10–20%), colitis (10–15%), hepatitis (5–10%), and pneumonitis (5–10%). Grade 3–4 irAEs — which are severe and require treatment interruption — occur in 15–60% depending on the agent (highest with dual CTLA-4 + PD-1 blockade combination). Management involves withholding immunotherapy and administering high-dose corticosteroids (prednisolone 1–2 mg/kg/day or IV methylprednisolone for severe cases), with immunosuppressive agents (infliximab, mycophenolate) for refractory cases. Early recognition is critical. Infusion reactions — chills, fever, urticaria — occur during monoclonal antibody infusions and are managed with antihistamines and slowed infusion rate. CAR-T therapy carries risk of cytokine release syndrome (CRS) in 70–90%, with grade 3–4 CRS in 20–30% requiring intensive care monitoring and tocilizumab administration. Hypophysitis (adrenal insufficiency) and endocrine irAEs may be permanent.

Patients receiving outpatient immunotherapy infusions are observed in the day unit for 1–2 hours post-infusion for immediate reactions before discharge. Ongoing monitoring throughout treatment includes blood tests every 2–3 weeks (full blood count, liver function, thyroid function, renal function, CRP) to detect subclinical irAEs before they become severe. Fatigue is the most common complaint and is managed with graded exercise, sleep hygiene optimisation, and nutritional support. Patients are educated on irAE symptoms requiring urgent medical review — new breathlessness (pneumonitis), diarrhoea more than 3 times daily (colitis), jaundice (hepatitis), or new rash — and given a steroid emergency card and 24-hour oncology contact. Treatment response is assessed at 8–12 weeks with CT imaging; pseudoprogression (apparent enlargement before response) is recognised and imaging is repeated at 4–6 weeks before abandoning treatment. Patients achieving complete response may be eligible for treatment cessation trials. Long-term follow-up monitoring every 3–6 months continues for at least 2–5 years after successful immunotherapy.