Disease management: pharmaceuticals, gene therapy, lifestyle: HSC Biology Module 8
“Investigate the treatment, management and possible future directions for the cure of non-infectious diseases through pharmaceutical intervention, gene therapy and lifestyle change”
Non-infectious disease is managed through layered pharmaceutical interventions (insulin, statins, CFTR modulators), emerging gene therapies that correct single-gene defects (Casgevy, Luxturna) and foundational lifestyle change (Mediterranean diet, exercise, smoking cessation), with the most effective treatment plans combining all three. Pharmaceuticals and lifestyle usually manage disease (ongoing), while gene therapy is potentially curative because it corrects the root genetic cause - but it is costly and limited to specific single-gene diseases. Strong answers name examples, tie each to a mechanism, and weigh strengths against limitations.
What this dot point is asking
NESA wants you to describe how non-infectious diseases are managed and possibly cured through pharmaceutical intervention, gene therapy and lifestyle change, with named examples and an honest evaluation of strengths and limits.
The answer
Treatment of non-infectious disease operates on three fronts: pharmaceutical (drugs that modify physiology), gene therapy (correction of the underlying genetic defect) and lifestyle change (behavioural modification of risk factors). Most chronic disease is managed by a combination of all three.
Pharmaceutical intervention
Pharmaceuticals modify physiology by targeting receptors, enzymes, transporters or ion channels. They are the workhorse of chronic disease management.
Hormone replacement.
- Insulin (recombinant human insulin since 1982) is essential for type 1 diabetes and used in advanced type 2 diabetes. Delivered by injection or insulin pump.
- Thyroxine (levothyroxine) replaces thyroid hormone in hypothyroidism.
Diabetes drugs.
- Metformin. First-line in type 2 diabetes. Reduces hepatic glucose output and improves insulin sensitivity.
- SGLT2 inhibitors (empagliflozin, dapagliflozin). Block glucose reabsorption in the kidney; also reduce cardiovascular events and slow kidney disease.
- GLP-1 receptor agonists (semaglutide). Stimulate insulin release and suppress appetite. Produces 10 to 15 percent weight loss; reduces cardiovascular events.
Cardiovascular drugs.
- Statins. Inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis. Lower LDL by 30 to 50 percent and reduce heart attack and stroke risk by approximately a quarter.
- Antihypertensives. ACE inhibitors, ARBs, beta blockers, calcium channel blockers and diuretics all lower blood pressure by different mechanisms.
- Antiplatelets and anticoagulants. Aspirin (irreversibly inhibits cyclooxygenase in platelets), clopidogrel, warfarin, direct oral anticoagulants (apixaban, rivaroxaban).
Targeted molecular therapies.
- CFTR modulators (ivacaftor, elexacaftor/tezacaftor/ivacaftor) bind the CFTR protein and restore its function in cystic fibrosis patients with specific mutations. Have transformed CF prognosis since 2012.
- Monoclonal antibodies. Trastuzumab targets HER2 in breast cancer; pembrolizumab is an immune checkpoint inhibitor used across multiple cancers.
Cancer chemotherapy. Cytotoxic agents (cisplatin, doxorubicin, paclitaxel) damage rapidly dividing cells; selective for cancer but with collateral toxicity to bone marrow, gut and hair follicles.
Gene therapy
Gene therapy modifies the patient's DNA to correct a genetic defect. Two main approaches:
Gene addition. A functional gene is delivered to the patient's cells, usually by a viral vector (adeno-associated virus, lentivirus).
- Luxturna (voretigene neparvovec). Approved 2017. Treats Leber congenital amaurosis caused by RPE65 mutations. A functional RPE65 gene is delivered to retinal pigment epithelial cells by AAV injection under the retina, partially restoring vision.
- Zolgensma. Approved 2019. Treats spinal muscular atrophy by AAV-delivered SMN1 gene. Single infusion in infancy can prevent lethal motor neuron loss.
Gene editing (CRISPR-Cas9). Cas9 nuclease guided by a short RNA precisely cuts a chosen DNA sequence, which the cell repairs through homology-directed repair (introducing a correct sequence) or non-homologous end joining (disabling a gene).
- Casgevy (exa-cel). Approved 2023. Treats sickle cell disease and beta-thalassaemia by editing BCL11A in patient bone marrow stem cells to reactivate fetal haemoglobin. Patients in trials are crisis-free.
Strengths. Potentially curative; targets root cause; one-time treatment.
Limitations. Cost (Casgevy approximately 3 million Australian dollars per patient); access (specialist centres only); off-target editing risk; ethical concerns around germline editing.
Lifestyle change
Lifestyle interventions modify behavioural risk factors and often work on multiple diseases at once.
Diet.
- Mediterranean diet (vegetables, legumes, whole grains, olive oil, fish, modest wine) reduces cardiovascular events by approximately 30 percent in trials (PREDIMED, 2013).
- DASH diet (Dietary Approaches to Stop Hypertension) lowers blood pressure by 8 to 14 mm Hg.
- Low-glycaemic and reduced-energy diets improve glycaemic control in type 2 diabetes; 5 to 10 percent weight loss can induce remission.
- Physical activity
- 150 minutes of moderate aerobic activity plus 2 sessions of resistance training per week reduces cardiovascular mortality by approximately 30 percent, improves insulin sensitivity, and reduces depression and dementia risk.
- Smoking cessation
- Halves the excess cardiovascular risk within 1 year; lung cancer risk approaches non-smoker rates after 15 to 20 years.
- Alcohol reduction
- Australian guidelines recommend no more than 10 standard drinks per week. Reduction reduces hypertension, atrial fibrillation, liver disease and several cancers.
- Sleep and stress
- Chronic sleep deprivation and unmanaged stress contribute to hypertension, insulin resistance and depression. Cognitive behavioural therapy is effective for both.
Comparing the three approaches
| Approach | Mechanism | Reach | Cost | Cure? |
|---|---|---|---|---|
| Pharmaceutical | Modifies physiology | Wide (millions on statins, metformin) | Moderate to high lifetime | No, ongoing |
| Gene therapy | Edits or replaces DNA | Narrow (single-gene disease) | Very high one-off | Potentially yes |
| Lifestyle | Removes risk factors | Universal | Low | Sometimes (T2DM remission) |
In practice these are layered: a person with type 2 diabetes might use metformin (pharmaceutical), Mediterranean diet and exercise (lifestyle), and, in the future, possibly gene editing of metabolic regulators (gene therapy).
Future directions
- CRISPR base editing and prime editing. Edit single bases without double-strand breaks, reducing off-target damage.
- In vivo CRISPR. Editing inside the body rather than ex vivo, reducing cost and complexity.
- mRNA therapeutics. Beyond vaccines, mRNA is being trialled for cancer (personalised neoantigen vaccines) and protein replacement.
- Polygenic risk scores. Use whole-genome sequencing to identify high-risk individuals before disease develops.
- AI-guided drug design. Models such as AlphaFold accelerate the identification of new drug targets.
- Microbiome modulation. Faecal microbiota transplant and engineered probiotics for inflammatory and metabolic disease.
Examples in context
Example 1. Trikafta (elexacaftor/tezacaftor/ivacaftor) for cystic fibrosis in Australia. Listed on the PBS in April 2022, Trikafta is a triple-combination small-molecule drug that corrects the F508del CFTR mutation underlying around 70 percent of cystic fibrosis cases. The three drugs work together: elexacaftor and tezacaftor act as "correctors" that help misfolded CFTR protein reach the cell membrane, while ivacaftor is a "potentiator" that opens the chloride channel once it arrives. Lung function (FEV1) improves by an average 14 percent within weeks of starting therapy, and pulmonary exacerbations drop by 63 percent. Sydney Children's Hospital cystic fibrosis clinics estimate that around 1500 Australian patients are now on Trikafta, transforming what was a paediatric-only disease into a manageable adult condition.
Example 2. Lifestyle intervention reverses early type 2 diabetes. The Diabetes Remission Clinical Trial (DiRECT), with results published in 2018 and replicated in Australian primary care contexts since, showed that a structured very-low-calorie diet of 800 kcal per day for 12 weeks followed by weight maintenance achieved remission of type 2 diabetes in 46 percent of recently diagnosed patients (within 6 years of diagnosis). Remission was sustained at 2 years in over a third. The mechanism is fat loss from the pancreas and liver, restoring insulin sensitivity. NSW Health endocrinology clinics now routinely offer Type 2 Diabetes Reversal programs alongside metformin and insulin. This is a striking example where lifestyle alone, supervised intensively, outperforms pharmaceutical-only management for selected patients.
Treatment of non-infectious disease works on three fronts: pharmaceutical (modify physiology), gene therapy (correct the DNA) and lifestyle change (remove risk factors) - and most chronic disease is managed by combining them. Pharmaceuticals (insulin, statins, CFTR modulators) and lifestyle change (Mediterranean diet, exercise) usually manage disease and continue indefinitely; gene therapy (Luxturna, Casgevy) is potentially curative because it fixes the root genetic cause, but is currently expensive and limited to specific single-gene diseases.
Worked example 1 - distinguish two approaches (3 marks)
Question. Distinguish between somatic gene therapy and pharmaceutical intervention for treating a genetic disease.
Model answer. Somatic gene therapy corrects the underlying mutation in the patient's body (somatic) cells - for example by delivering a functional gene with a viral vector - so it targets the root cause and is potentially a one-time, curative treatment for that patient (the change is not passed to offspring). Pharmaceutical intervention instead compensates for the missing protein or manages the symptoms - for example giving a replacement enzyme or a drug that modifies physiology - and must be taken continuously because it does not correct the gene itself.
Marker's note: 1 mark for somatic gene therapy correcting the mutation in body cells, 1 mark for pharmaceuticals compensating/managing rather than curing, 1 mark for the explicit contrast (corrects cause and potentially curative vs. ongoing symptom control). Describing only one approach caps at 2 marks.
Worked example 2 - multimodal management of type 2 diabetes (6 marks)
Question. A 45-year-old woman is diagnosed with type 2 diabetes (HbA1c 8.5 percent, BMI 32, blood pressure 145/95, LDL 4.2 mmol/L). Describe a management plan that combines pharmaceutical intervention and lifestyle change, and comment on whether gene therapy applies.
Model answer. Lifestyle is the foundation: a dietitian-supervised Mediterranean, low-glycaemic, reduced-energy plan aiming for 7 to 10 percent weight loss, plus about 150 minutes of moderate exercise weekly; sustained weight loss can push early type 2 diabetes into remission. Pharmaceuticals add measurable risk reduction: metformin to lower glucose, perindopril (an ACE inhibitor) for the raised blood pressure, and atorvastatin (a statin) for the high LDL, with semaglutide added if HbA1c stays above target. Surveillance uses three-monthly HbA1c and annual eye, foot and kidney review. Gene therapy is not applicable here, because type 2 diabetes is a complex polygenic disease and current gene therapies treat single-gene disorders. A pragmatic combination targets several disease processes at once.
Marker's note: marks for a named lifestyle intervention with a mechanism, named pharmaceuticals each tied to the abnormality they correct (glucose, blood pressure, LDL), and the correct statement that gene therapy does not yet apply to polygenic type 2 diabetes. A list of drugs with no link to the patient's specific abnormalities is capped.
Worked example 3 - evaluate gene therapy (7 marks)
Question. Evaluate the role of gene therapy in treating genetic disease. Identify one approved gene therapy and the disease it treats, identify one major limitation, and justify whether gene therapy will replace pharmaceutical management within the next decade.
Model answer. Gene therapy can be transformative: Casgevy uses CRISPR editing of BCL11A in bone-marrow stem cells to reactivate fetal haemoglobin and leaves sickle cell patients crisis-free (alternatively, Luxturna delivers a functional RPE65 gene by AAV to partly restore vision). Its great strength is that it targets the root genetic cause, so it is potentially curative in a single treatment. However, a major limitation is cost and access - Casgevy is around 3 million Australian dollars per patient and is available only at specialist centres - alongside off-target editing risk and its restriction to specific single-gene diseases. Judgement: gene therapy will not broadly replace pharmaceutical management within a decade, because most chronic disease is common and polygenic (managed cheaply at scale by pharmaceuticals and lifestyle), whereas gene therapy remains costly and narrow; the two will stay complementary, with gene therapy reserved for rare single-gene disorders.
Marker's note: 2 marks for a correctly named therapy and its disease with mechanism, 2 marks for a genuine limitation explained, 3 marks for a justified judgement that weighs cost/reach/scope and reaches an explicit conclusion. An answer that lists features without a supported judgement cannot reach the top band.
- Saying pharmaceuticals "cure" chronic disease
- Most pharmaceuticals manage disease; they need to be taken indefinitely.
- Treating gene therapy as a near-future panacea
- It is curative for specific single-gene diseases but unlikely to be widely deployed for complex polygenic disease soon.
- Underrating lifestyle
- The PREDIMED trial of the Mediterranean diet showed cardiovascular event reduction comparable to statins. Lifestyle should not be treated as a soft option.
- Forgetting cost and access
- A treatment that exists but is not accessible (Casgevy, Zolgensma) has limited public-health impact.
- Always name examples
- "Pharmaceutical intervention" earns little; metformin, statins (HMG-CoA reductase), CFTR modulators, Luxturna (RPE65), Casgevy (BCL11A / sickle cell) earn marks. Tie each named treatment to its mechanism or target disease.
- Match depth to the command word
- "Outline" wants brief points; "describe" wants the steps in order; "compare" wants the same criteria for both approaches (mechanism, reach, cost, cure); "evaluate" demands a justified judgement that weighs strengths against limitations.
- Use the manage-versus-cure distinction
- State clearly that pharmaceuticals and lifestyle usually manage disease (ongoing), while gene therapy is potentially curative (one-off). Markers reward this contrast.
- For gene therapy, give the chain
- Engineered virus carries the gene -> enters the target cell -> gene is expressed -> functional protein corrects the defect. Add a real limitation (cost, access, off-target, single-gene scope) whenever you praise its potential.
Think of a non-infectious disease like type 2 diabetes as a leaky boat. Lifestyle change - eating better and exercising - is like bailing out the water and patching the small holes yourself; it is cheap, helps with almost any boat, and can sometimes fix the problem for good. Pharmaceuticals are like a pump that keeps running to hold the water down; reliable and widely used, but you have to keep it switched on. Surgery is a one-off repair for a serious hole when nothing else is enough. Gene therapy is the boldest idea: rebuild the part of the boat that was wrongly made in the first place - a potential permanent fix - but right now it is expensive and only works for boats with one specific known fault. In real life, doctors usually combine these rather than picking just one.
Exam-style questions
Questions in the style of NESA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
2020 HSC-style3 marks[An indicator of kidney function is GFR; a healthy adult has GFR >100 mL/min, and a patient needs dialysis when GFR <15 mL/min.] Explain how dialysis compensates for the loss of a function of the kidneys.Show worked answer →
Marks are awarded for describing a process in dialysis AND relating it to the lost kidney function.
- Identify the lost function: loss of kidney function means a failure to remove urea (a waste product) from the blood.
- Describe the dialysis process: blood from the patient passes through selectively (semi-)permeable dialysis tubing next to dialysate fluid.
- Link by mechanism: because urea moves by diffusion from its high concentration in the blood to the low concentration in the dialysate (down the concentration gradient), urea is removed from the blood.
Marker note: say diffusion (not osmosis) and that it removes urea (not vaguely 'cleans the blood'); the top mark needs the process explicitly tied to restoring the kidney's excretory function.
Source: NESA 2020 HSC Biology examination and marking guidelines.
Practice questions
Original practice questions graded from foundation to exam level, each with a full worked solution. Try them before revealing the solution.
foundation2 marksDistinguish between the treatment and the management of a non-infectious disease.Show worked solution →
1 mark - treatment. Treatment is intervention intended to cure the disease or correct its underlying cause - for example, gene therapy that replaces a faulty gene, or surgery that removes a tumour.
1 mark - management. Management is ongoing intervention to control symptoms and slow progression without curing the disease - for example, taking insulin or statins indefinitely, or maintaining a Mediterranean diet.
The mark hinges on the contrast: treatment aims to resolve the disease, management aims to control it long-term. An answer that uses the two words interchangeably caps at 1 mark.
foundation3 marksOutline how each of pharmaceutical intervention, gene therapy and lifestyle change can be used to address type 2 diabetes.Show worked solution →
- 1 mark - pharmaceutical
- A drug such as metformin lowers blood glucose (it reduces hepatic glucose output and improves insulin sensitivity); other drugs (SGLT2 inhibitors, GLP-1 agonists) add further glucose control and weight loss.
- 1 mark - lifestyle change
- A reduced-energy / low-glycaemic diet plus regular exercise lowers body fat, restoring insulin sensitivity; 5 to 10 percent weight loss can push early type 2 diabetes into remission.
- 1 mark - gene therapy
- Gene therapy is not yet standard for type 2 diabetes (a complex polygenic disease), but is a possible future direction for high-risk genetic subtypes by editing metabolic-regulator genes.
Each approach must be tied to a specific mechanism or example; naming the approach without a named drug, behaviour or limitation does not earn the mark.
foundation2 marksDefine gene therapy and distinguish between its two main approaches.Show worked solution →
1 mark - definition. Gene therapy modifies the patient's DNA to correct the genetic defect causing a disease.
1 mark - two approaches. Gene addition delivers a functional copy of a gene (usually by a viral vector) without removing the faulty gene; gene editing (CRISPR-Cas9) precisely cuts and repairs the existing DNA at a chosen site.
Both approaches must be named and contrasted (add a working copy vs. edit the existing sequence) for the second mark.
core4 marksExplain how a viral vector is used to deliver a corrected gene in gene-addition therapy, using a named example.Show worked solution →
- 1 mark - the vector
- A virus (for example an adeno-associated virus, AAV) is modified so its disease-causing genes are removed and a functional copy of the target gene is inserted in their place; the virus keeps only its ability to enter cells.
- 1 mark - delivery
- The recombinant virus is introduced to the patient's target cells (for Luxturna, AAV carrying a functional RPE65 gene is injected under the retina into retinal pigment epithelial cells).
- 1 mark - gene expression
- The viral vector enters the cell and the delivered gene reaches the nucleus, where it is transcribed and translated to produce the functional protein the patient previously lacked (functional RPE65 enzyme).
- 1 mark - outcome
- The restored protein corrects the cellular defect (RPE65 restores the retinoid cycle, partially restoring vision in Leber congenital amaurosis).
Marks require the chain: engineered virus carries gene -> enters target cell -> gene is expressed -> functional protein corrects the defect. A named example (Luxturna/RPE65, Zolgensma/SMN1) is needed for full marks.
core5 marksCompare pharmaceutical intervention and gene therapy as approaches to treating non-infectious disease, referring to mechanism, reach, cost and whether each offers a cure.Show worked solution →
Award up to 5 marks for a genuine comparison (similarities and differences across the stated criteria).
- Mechanism (1 mark)
- Pharmaceuticals modify physiology by targeting receptors, enzymes, transporters or ion channels (statins inhibit HMG-CoA reductase). Gene therapy instead edits or replaces the DNA itself to correct the root genetic cause.
- Reach (1 mark)
- Pharmaceuticals have wide reach - millions take statins or metformin for common, often polygenic, conditions. Gene therapy has narrow reach - it currently targets specific single-gene disorders (sickle cell, RPE65 blindness).
- Cost (1 mark)
- Pharmaceuticals are moderate cost but lifelong (ongoing expense). Gene therapy is a very high one-off cost (Casgevy approximately 3 million Australian dollars per patient) but a single treatment.
- Cure (1 mark)
- Pharmaceuticals generally manage disease and must be taken indefinitely. Gene therapy is potentially curative because it corrects the underlying defect.
- Judgement / synthesis (1 mark)
- A complete answer notes both are valuable for different problems: pharmaceuticals for common chronic disease, gene therapy for rare single-gene disorders where a one-time cure justifies the cost.
A response that describes one approach only, or lists features without comparing the same criteria for both, does not reach full marks.
core4 marksThe PREDIMED trial (2013) found the Mediterranean diet reduced cardiovascular events by about 30 percent, comparable to statin therapy. Using this, evaluate the claim that lifestyle change should be regarded as a soft option compared with pharmaceuticals.Show worked solution →
- 1 mark - evidence for lifestyle
- PREDIMED is a large randomised trial showing the Mediterranean diet cut cardiovascular events by approximately 30 percent, a reduction comparable to statins - so lifestyle change produces clinically meaningful, measurable benefit.
- 1 mark - strengths of lifestyle
- Lifestyle change is low cost, universally applicable, and addresses risk factors at their root; it can act on several diseases at once (cardiovascular, diabetes, some cancers) and can drive type 2 diabetes into remission.
- 1 mark - limitations of lifestyle
- Its weakness is adherence: sustained behaviour change is hard, effects are slower than a drug, and some conditions still need pharmaceuticals; benefit depends on the patient maintaining the change.
- 1 mark - judgement
- A supported conclusion: the evidence rejects the "soft option" label - lifestyle change is a foundational, evidence-based intervention, best layered with pharmaceuticals rather than treated as inferior to them.
Full marks need trial evidence, weighed strengths and limitations, AND an explicit justified judgement. Stating an opinion without the PREDIMED evidence caps below full marks.
exam7 marksA 45-year-old patient is newly diagnosed with type 2 diabetes (HbA1c 8.5 percent, BMI 32, blood pressure 145/95, LDL 4.2 mmol/L). Evaluate a management plan that combines pharmaceutical intervention, lifestyle change and (as a future direction) gene therapy for this patient.Show worked solution →
"Evaluate" requires a judgement that weighs the strengths and limitations of each approach against this patient's needs. A Band 6 response reaches a reasoned, integrated conclusion.
- Lifestyle change (2 marks)
- Foundational and addresses the cause: a reduced-energy, low-glycaemic / Mediterranean diet plus 150 minutes of exercise weekly targets the raised HbA1c, BMI, blood pressure and LDL simultaneously. 5 to 10 percent weight loss can induce remission of early type 2 diabetes (DiRECT trial). Strength: cheap, multi-target, potentially curative. Limitation: depends on sustained adherence and is slower than drugs.
- Pharmaceutical intervention (2-3 marks)
- Provides reliable, measurable risk reduction now: metformin for glucose, an ACE inhibitor / antihypertensive for the raised blood pressure, a statin for the high LDL, with semaglutide (GLP-1 agonist) added if glucose stays high (also driving weight loss). Strength: wide reach, evidence-based, fast acting. Limitation: manages rather than cures, must be taken indefinitely, has side effects.
- Gene therapy (1 mark)
- Not yet applicable here: type 2 diabetes is a complex polygenic condition, and current gene therapies target single-gene disorders. It is a possible future direction for high-risk genetic subtypes, but is currently very costly and unproven for this disease.
- Judgement (1-2 marks)
- A supported conclusion: the optimal plan layers lifestyle change (the foundation) with targeted pharmaceuticals (immediate, measurable risk reduction), monitors HbA1c and complications, and reserves gene therapy as a future possibility, not a current option. An answer that lists treatments without weighing them or without an explicit judgement caps below full marks.
exam6 marksGene therapy is often described as a potential cure for genetic disease, yet it has not replaced pharmaceutical management. Discuss the strengths and limitations of gene therapy that explain this, using named examples.Show worked solution →
Target a sequenced response that weighs genuine strengths against genuine limitations, anchored in named therapies.
- Strengths (2-3 marks)
- Gene therapy targets the root genetic cause rather than symptoms, so it is potentially curative and can be a one-time treatment. Named examples: Casgevy (CRISPR editing of BCL11A to reactivate fetal haemoglobin) leaves sickle cell patients crisis-free; Zolgensma (AAV-delivered SMN1) given once in infancy can prevent lethal motor-neuron loss in spinal muscular atrophy; Luxturna (AAV-delivered RPE65) partially restores vision.
- Limitations (2-3 marks)
- Cost is extreme (Casgevy approximately 3 million Australian dollars per patient), limiting access to specialist centres only. There is an off-target editing risk with CRISPR, and ethical concerns about germline editing. It currently works only for specific single-gene diseases, not the common polygenic conditions that pharmaceuticals manage at population scale, and the durability of correction is still being established.
- Conclusion (1 mark)
- A judgement: gene therapy is transformative for rare single-gene disorders but cannot yet replace pharmaceuticals for the bulk of chronic disease, mainly because of cost, access and its single-gene scope - so the two remain complementary.
Full marks need named examples on BOTH sides of the discussion (strengths and limitations) plus a reasoned concluding judgement.
Practise this
Sources & how we know this
- Biology Stage 6 Syllabus (2017) — NESA
- Biology HSC exam papers — NESA