Gene Therapy Dose Calculator
Calculate total vector genome dose from patient weight and target vg/kg for AAV and lentiviral gene therapies.
About this calculator
Gene therapy dosing is expressed in vector genomes per kilogram (vg/kg) rather than a mass-based dose, because what matters biologically is roughly how many viral particles reach each kilogram of tissue, not how many milligrams of protein or nucleic acid are delivered. This calculator multiplies your entered dose (given as a coefficient times 10 raised to an exponent, e.g. 1.1 × 10^14) by patient weight to get total vector genomes needed, then works backward through manufacturing: dividing that total by your fill volume gives the drug product concentration each vial must hit, and dividing it by your virus yield (vg/mL from harvest) gives the raw stock volume required before formulation losses. A flat overfill percentage is added on top to cover QC testing, dead volume, and filling variance, and the result is converted into a run count assuming a fixed 500 mL harvest per bioreactor batch.
Results are also reported in log10 form because vector genome counts routinely span 10^11 to 10^14+ and clinicians and manufacturers compare doses on a log scale as a matter of convention. Getting the exponent and coefficient split correct matters most — entering 13 as the exponent means 10^13, not 13; a single off-by-one here changes the computed dose, and therefore the manufacturing volume, by a full order of magnitude. This tool is a planning aid for translating a target vg/kg into manufacturing volumes and run counts; it does not account for vector potency assays, empty/full capsid ratios, or the clinical judgment that sets the actual dose for a given indication.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
This tool estimates a starting point only and is not a validated clinical decision-support system. It does not account for every patient-specific factor (organ function, drug interactions, allergies, comorbidities, or current clinical status). Any dose, rate, or setting must be independently verified by the treating clinician and pharmacist or respiratory therapist against current institutional protocols, product labeling, and the patient's full clinical picture before being administered or applied.
Inputs
Results
Total dose (vg)
700,000,000,000,000
How to Use This Calculator
- Enter patient weight (kg), dose coefficient, and dose exponent (10^n vg/kg).
- Set virus yield (vg/mL), fill volume per vial (mL), and manufacturing overfill (%).
- Review Total Dose (vg), Required Concentration (vg/mL), and Stock Needed (mL).
- Use Bioreactor Runs Needed to plan manufacturing capacity for clinical or commercial supply.
How the result changes with Dose exponent (10^n vg/kg)
| Dose exponent (10^n vg/kg) | Total dose (vg) |
|---|---|
| 8 | 7,000,000,000 |
| 9.75 | 394,000,000,000 |
| 16 | 700,000,000,000,000,000 |
What each input means
- Patient weight (kg)
- Patient body weight in kilograms.
- Dose coefficient
- Coefficient of the dose (e.g., 1.1 for 1.1×10^n vg/kg).
- Dose exponent (10^n vg/kg)
- Exponent for dose in vg/kg. Example: 13 = 10^13 vg/kg. Zolgensma uses ~1.1×10^14.
- Virus yield (vg/mL)
- Viral vector yield from manufacturing in vg per mL of harvest.
- Fill volume per vial (mL)
- Volume per vial for final drug product.
- Manufacturing overfill (%)
- Extra manufacturing volume for losses, QC testing, and overfill.
What each result means
- Total dose (vg)
- Total vector genomes required for this patient.
- Total dose (log10 vg)
- Log10 of total vector genomes for easy comparison.
- Dose per kg (vg/kg)
- Vector genomes per kilogram of body weight.
- Required conc. (vg/mL)
- Required viral concentration in the fill volume.
- Stock needed (mL)
- Total volume of virus stock required including overfill.
- Bioreactor runs needed
- Estimated number of 500 mL bioreactor runs to produce needed stock.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersPatient weight (kg) = 70, Dose coefficient = 1, Dose exponent (10^n vg/kg) = 13, Virus yield (vg/mL) = 1000000000000 = 6 input(s) provided
- Calculate Total doseTotal dose = Number(totalVg.toExponential(2))700000000000000 = 700000000000000
- Calculate Total doseTotal dose = log10(totalVg)14.85 = 14.85
- Calculate Dose per kgDose per kg = Number(dosePerKg.toExponential(2))10000000000000 = 10000000000000
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why is dose entered as a coefficient and exponent instead of a plain number?
AAV and lentiviral doses span roughly 10^8 to 10^16 vg/kg, so entering it as a coefficient (0.1-10) times 10 raised to an exponent (8-16) avoids typing enormous numbers with many zeros and reduces the chance of miscounting digits. The calculator reconstructs the actual dose per kg by multiplying doseCoefficient by 10^doseExponent, so a coefficient of 1.1 with exponent 14 gives 1.1×10^14 vg/kg, matching how doses are reported in gene therapy literature and package inserts.
How does the calculator determine the number of bioreactor runs needed?
It divides the total stock volume needed, including overfill, by a fixed harvest assumption of 500 mL per bioreactor run, then rounds up to the next whole run since you can't do a fractional run. This is a simplifying planning assumption — actual harvest volume per run depends heavily on your specific bioreactor scale and process, so treat runsNeeded as a rough manufacturing-capacity estimate rather than a fixed schedule.
What does the overfill percentage account for, and why is it applied after computing stock needed?
Overfill covers volume lost to QC testing, dead volume in vials and lines, and normal variance during formulation and fill-finish. It's applied as a multiplier on top of the raw stock volume calculated from your virus yield, so a 20% overfill means you need 1.2x the theoretical minimum stock volume to reliably fill every vial to spec.
Why are the log10 values reported alongside the raw vector genome numbers?
Vector genome counts for gene therapies commonly range from 10^11 to over 10^14, and researchers and regulators conventionally compare doses on a log scale rather than by their linear values because the relevant differences are typically measured in orders of magnitude. The log10 columns let you quickly see how a dose compares to reference doses reported the same way in the literature.
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