About This Guide
This guide provides supplementary information for the Tremfya (guselkumab) Dosing Calculator. It outlines the tool’s functions, explains the dosing schedules it calculates, and offers clinical context based on the approved prescribing information. Use this information to better understand the calculator’s outputs for patient management and education.
Calculator Outputs Explained
The tool generates dosing schedules based on the selected indication and calculation type. The key outputs include:
- Full Dosing Schedule: When selecting “Generate Full Schedule,” the tool projects a series of administration dates starting from the first dose. It clearly distinguishes between induction and maintenance phases for each indication.
- Next Dose Calculation: For patients already on therapy, this option calculates the specific date for the next dose based on the date and type of the last administration.
- Indication-Specific Dosing: The calculator automatically applies the correct dosing regimen, whether it’s the fixed 100 mg subcutaneous (SC) dose for Plaque Psoriasis (PsO) / Psoriatic Arthritis (PsA) or the weight-based intravenous (IV) induction followed by fixed SC maintenance for Ulcerative Colitis (UC).
How to Use the Calculator
Follow these steps to generate an accurate dosing schedule:
- Select Indication: Choose between “Plaque Psoriasis (PsO) / Psoriatic Arthritis (PsA)” or “Ulcerative Colitis (UC)”. This is the most critical step as it determines the entire dosing algorithm.
- Enter Patient Weight (for UC only): If UC is selected, the patient weight field will appear. Enter the weight and select the unit (kg or lbs) to calculate the correct weight-based IV induction dose.
- Choose Calculation Type: Select “Generate Full Schedule” for new patients or “Calculate Next Dose Only” for existing patients.
- Input Relevant Dates: Based on the calculation type, provide either the “Date of First Dose” or the “Date of Last Dose” and “Type of Last Dose”.
- Calculate: The tool will display the resulting schedule, dose, route, and projected dates.
Dosing Overview
The calculator’s logic is based on the FDA-approved dosing regimens for Tremfya. Below is a summary of the standard schedules.
| Indication | Phase | Dose & Route | Frequency |
|---|---|---|---|
| Plaque Psoriasis / Psoriatic Arthritis | Induction | 100 mg SC | At Week 0 and Week 4 |
| Maintenance | 100 mg SC | Every 8 weeks thereafter | |
| Ulcerative Colitis | Induction | Weight-based IV infusion* | Once at Week 0 |
| Maintenance | 200 mg SC | At Week 12, then every 4 weeks |
*UC IV Induction Dose by Weight: <55 kg = 200 mg; 55 kg to 90 kg = 300 mg; >90 kg = 450 mg. This must be administered by a healthcare professional over at least 30 minutes.
Switching Therapies
This calculator does not provide guidance for switching from another biologic to Tremfya. The decision to switch, including washout periods or loading dose adjustments, requires careful clinical evaluation of the patient’s disease activity, previous treatments, and risk factors. Always consult the full prescribing information and relevant clinical guidelines when considering a therapy switch.
Missed Dose Protocol
The tool assumes on-time administration and does not calculate adjustments for a missed dose. If a patient misses a dose, general guidance is to administer it as soon as possible. The subsequent maintenance dose should then be rescheduled based on the date of this last injection, maintaining the recommended interval (e.g., every 8 weeks for PsO/PsA, every 4 weeks for UC maintenance). This approach should be confirmed with clinical judgment.
Safety Alerts
This tool is for informational purposes and is not a substitute for clinical judgment or the full Prescribing Information. Tremfya may increase the risk of infection. Evaluate patients for tuberculosis (TB) infection prior to initiating treatment. Please refer to the latest official Prescribing Information for a complete list of contraindications, warnings, precautions, and adverse reactions.
Frequently Asked Questions (FAQ)
The approved dosing for UC includes a one-time, weight-based intravenous induction dose to establish therapeutic levels quickly. The PsO/PsA regimen uses a standard, fixed 100 mg subcutaneous dose for all patients, regardless of weight.
The calculator uses a “less than or equal to” logic for the upper bounds. For a patient weighing exactly 90 kg, the tool will calculate the 300 mg IV dose, as per the prescribing information.
No. The safety and effectiveness of Tremfya have not been established in pediatric patients. The dosing information used in this tool is for adults only.
The tool typically calculates the induction doses plus the first several maintenance doses, projecting the schedule approximately one year from the start date to help with long-term planning.
No. This is a scheduling tool based on standard dosing. Any deviation from the standard regimen, including dose interruption or discontinuation, must be based on a healthcare professional’s clinical assessment.
The maintenance schedules are indication-specific and based on clinical trial data. UC requires more frequent dosing (200 mg SC every 4 weeks) to maintain efficacy compared to PsO/PsA (100 mg SC every 8 weeks).
For the “Calculate Next Dose” function, enter the actual date the last dose was given. The tool will calculate the next due date based on the standard interval from that actual date. Always use clinical judgment to determine if the treatment plan needs further adjustment.
The calculator uses a standard date picker (YYYY-MM-DD) for input and displays dates in a common MM/DD/YYYY format. Be mindful of your browser’s local settings, but the calculations are based on universal time intervals (weeks).
References
- TREMFYA® (guselkumab) Prescribing Information. Janssen Biotech, Inc. Horsham, PA. Available at: FDA.gov
- TREMFYA® Healthcare Provider Information. Janssen Immunology. Available at: tremfyahcp.com
- U.S. Food and Drug Administration. Drugs@FDA Database: Tremfya (guselkumab). Available at: accessdata.fda.gov
- Deodhar A, Helliwell PS, Boehncke WH, et al. Guselkumab in patients with active psoriatic arthritis who were biologic-naive or had previously received TNFα inhibitor treatment (DISCOVER-1): a double-blind, randomised, placebo-controlled phase 3 trial. Lancet. 2020;395(10230):1115-1125.
