Gene Therapy — Types, Techniques, India’s First Approvals (UPSC Science & Tech)

In October 2023, India approved its first indigenous cell and gene therapy, Nexcar19, developed by IIT Bombay spin-off ImmunoACT at a price of ~₹40 lakh — one-tenth of imported CAR-T therapies. In December 2023, the US FDA approved Casgevy, the world's first CRISPR-based gene therapy for sickle cell disease. Gene therapy is transitioning from experimental to standard-of-care medicine. For UPSC GS III, the theme sits in biotechnology, health, ethics and indigenisation.

What is Gene Therapy

Gene therapy modifies genes inside a patient's cells to treat or cure disease. Mechanisms include:

• Replacing a disease-causing gene with a healthy copy.
• Inactivating a malfunctioning gene.
• Introducing a new gene to fight disease.

Types

Somatic Gene Therapy

• Modifies genes in any non-reproductive cell.
• Changes affect only the treated individual; not inherited.
• Current focus of gene therapy research due to safety and ethics.

Germline Gene Therapy

• Modifies genes in sperm, egg or embryo.
• Changes pass to future generations.
• Banned in most countries, including India, due to ethical concerns.
• The 2018 Chinese CRISPR-edited babies scandal led to global condemnation.

Gene Therapy Products (GTPs)

Any biological substance carrying genetic material into cells to treat disease. Components:

• Therapeutic gene — The payload.
• Vector — The delivery vehicle.
• Regulatory elements — Promoters, enhancers.

Vector Types

• Plasmid DNA — Engineered circular DNA.
• Viral vectors — Modified viruses that deliver genes (AAV, lentivirus, adenovirus).
• Bacterial vectors — Modified bacteria.
• Human gene editing technology — CRISPR, TALEN, zinc finger nucleases.
• Patient-derived cellular products — Cells removed, modified, returned (CAR-T).

Gene Editing Techniques

CRISPR-Cas9

• Based on a bacterial defence mechanism.
• Cas9 enzyme guided by RNA to cut DNA at specific sites.
• Enables targeted disruption or correction of genes.
• 2020 Nobel Prize in Chemistry to Jennifer Doudna and Emmanuelle Charpentier.
• CRISPR-Cas13 — RNA-level editing.

Prime Editing

• "Search-and-replace" technique.
• Writes new genetic code directly at target site.
• Lower off-target risk than Cas9.

Meganucleases and TALENs

• Older but still useful genome editors.
• Higher specificity; harder to engineer.

Base Editing

• Converts single DNA letters without cutting the double helix.
• Used in 2022 UK leukaemia trial with breakthrough results.

Applications

Cancer

• CAR-T cell therapy — Modified T-cells attack blood cancers.
• Oncolytic viruses — Engineered viruses that selectively kill tumours.
• Tumour suppressor gene therapy.

Genetic Disorders

• Sickle cell disease — Casgevy approved 2023.
• Beta thalassemia.
• Haemophilia — BioMarin's Roctavian approved.
• Cystic fibrosis.
• Duchenne muscular dystrophy.

Neurological Disorders

• Spinal Muscular Atrophy (SMA) — Zolgensma.
• Parkinson's, Alzheimer's — In trials.

Cardiovascular

• Heart failure, coronary artery disease under investigation.

Infectious Disease

• HIV/AIDS gene therapy trials.

Others

• Rare metabolic diseases.
• Inherited blindness (Luxturna for RPE65 mutation).

National Guidelines for Gene Therapy Product Development and Clinical Trials (ICMR, 2019)

• Nodal body — Indian Council of Medical Research (ICMR).
• GTAEC (Gene Therapy Advisory and Evaluation Committee) — Overarching oversight body, secretariat at ICMR.
• Scope — All stages: preclinical, clinical trials, post-market surveillance.
• Focus on rare diseases — Unmet clinical need.
• Ethical emphasis — Informed consent, patient safety.
• CMC — Chemistry, manufacturing, control.
• Infrastructure and personnel standards.
• New Drugs and Clinical Trials Rules 2019 (CDSCO) — Classifies GTPs as "new drugs."

Challenges

• Delivery efficiency — Getting the therapy to the right cells.
• Immune response — Body rejection of vectors.
• Long-term effects — Still being studied.
• Cost — Zolgensma costs ~$2.1 million per dose; Casgevy over $2 million.
• Manufacturing complexity — Patient-specific vs off-the-shelf.
• Off-target edits — Unintended mutations.
• Access equity — Especially in LMICs.

India's Landscape

• Nexcar19 / ActalyCAbtagene ciloleucel (2023) — ImmunoACT, IIT Bombay. Approved for relapsed B-cell leukaemia/lymphoma at ~₹40 lakh.
• NexMeso — Pipeline mesothelioma therapy.
• CMC Vellore sickle cell gene therapy trials (2024-25).
• CSIR-IGIB CRISPR trials for sickle cell.
• Bharat Biotech, Biocon Biologics — GTP R&D.
• Tata Medical Center, Kolkata — CAR-T infusions.
• NIBMG Kalyani, ACTREC Mumbai — Translational research.

Ethical and Regulatory Issues

• Germline editing ban — India's stance is cautious.
• Consent for minors — Paediatric gene therapy demands parental consent with longer follow-up.
• Genetic non-discrimination — India lacks a specific law (contrast: US GINA 2008).
• DPDP Act 2023 — Genetic data = sensitive personal data.
• Embryo and reproductive technology — Regulated under Assisted Reproductive Technology Act 2021 and Surrogacy Act 2021.
• Enhancement vs therapy — Society must decide limits.

Latest Developments (2024-26)

• Casgevy approved in US (Dec 2023), UK (Nov 2023), EU (2024) — First CRISPR therapy.
• India CRISPR sickle cell trials at CMC Vellore.
• BioE3 Policy (2024) — Precision biotherapeutics as priority.
• ImmunoACT expansion — More cancer indications.
• Prime Medicine, Verve Therapeutics — Prime and base editing trials globally.
• India Semiconductor Mission — Sequencing chips on DLI priority list.
• National Quantum Mission (2023) — Quantum biology for drug discovery.
• AI policy (IndiaAI Mission, 2024) — AI protein folding for GTP design.
• DPDP Act 2023 compliance for clinical trial data.
• Chandrayaan-4 — Space biology payloads include gene expression studies.
• Gaganyaan — Astronaut DNA damage studies in microgravity.

UPSC Relevance

Prelims angles

• Gene therapy types: somatic, germline.
• Gene editing: CRISPR-Cas9, prime editing, TALEN, meganucleases.
• ICMR Gene Therapy Guidelines — 2019.
• GTAEC — committee name.
• CAR-T — Nexcar19 approved 2023.
• Casgevy — first CRISPR therapy, 2023.
• CDSCO, New Drugs and Clinical Trials Rules 2019.

Mains angles

• GS III — Biotechnology: "Gene therapy and India's indigenous CAR-T as a frugal innovation."
• GS IV — Ethics: "Discuss the ethical dilemmas of germline gene editing."
• GS III — Health: "Rare diseases and the role of gene therapy."

Essay angles

• "Editing life — promise and peril."
• "From billion-dollar therapies to 40-lakh CAR-T — India's price disruption."

Practice question — "Gene therapy is on the verge of moving from experimental to mainstream. Discuss with Indian examples."

Gene therapy turns disease management into disease cure. India's frugal CAR-T at one-tenth the global price is the kind of leapfrog that defined Indian pharma in the generics era — now repeating in the biologics and cell-therapy age.