Production Constraints

Overview

Production constraints define the manufacturing limitations and safety stock rules that govern your clinical trial's kit supply. They answer three critical questions:

• How fast can you make kits? Your manufacturer has a lead time — the gap between placing an order and receiving finished kits.
• How many kits per run? Manufacturing happens in batches with minimum and maximum quantities.
• How much buffer stock should you hold? Overage percentages and seed amounts ensure you have enough kits to handle enrollment variability and avoid shortages.

Without production constraints, Prognosis cannot calculate a realistic supply plan. These settings directly feed into the supply-demand forecast, determining whether you will have enough kits before demand peaks, how much inventory to hold, and when to initiate manufacturing runs.

Production Settings

Production settings control manufacturing timing and capacity. You choose how these settings apply:

Production Settings Mode

Start with "All Kit Types" unless you know your kits have different manufacturing parameters.

Key Fields

Validation rules:

• Production lead time must be greater than 0
• If both min and max quantities are specified, max must be greater than or equal to min
• Frequency of production must be greater than 0

Per-Kit Production Settings

When you select "Per Kit Type" mode, a tabbed interface appears with one tab per kit defined in Step 3. Each tab contains the same fields as above, scoped to that specific kit. This lets you model different manufacturers or production lines accurately — for example, an active drug kit with a complex formulation might have a 6-week lead time while a placebo kit needs only 2 weeks.

Safety Stock Configuration

Safety stock settings determine how much buffer inventory you maintain to protect against enrollment variability and supply disruptions.

Safety Stock Unit

Global Safety Stock

Kit-Level Overrides

Even in global mode, you can override the overage percentage and seed amount for individual kits. This is useful when certain kits are more expensive or have shorter shelf lives:

Kit-level overrides are available in all three modes (global, per-country, and per-depot).

Per-Country Safety Stock

When set to "Per Country," you configure overage and seed values for each country from Step 1:

Use the Copy Safety Stock Configuration feature to copy one country's settings to others, then adjust as needed.

Per-Depot Safety Stock

When set to "Per Depot," you configure overage and seed values for each depot from Step 1:

Custom Lot Configurations

Custom lot configurations let you define specific manufacturing batches with known dates, quantities, and label group assignments. These represent real or planned manufacturing lots that Prognosis accounts for in the forecast.

When to Use Custom Lots

• You have a confirmed manufacturing schedule with specific lot numbers and quantities
• You need to track expiry dates for regulatory compliance
• Different lots serve different label groups (and therefore different countries)
• You want the forecast to account for known incoming supply

Custom Lot Fields

Custom lots are especially useful for modeling initial supply. Enter confirmed manufacturing batches so the forecast starts with accurate initial inventory.

How Production Constraints Affect Forecasts

Example Scenario

Consider a trial with these parameters:

From earlier steps:

• 3 countries, 1 central depot
• 150 patients enrolled over 4 months (Jan to Apr 2025)
• 6 visits per patient over 6 months
• 2 kit types: Active Drug (Kit A) and Placebo (Kit B)
• Total demand: approximately 900 kits

Production constraints configured:

• Production lead time: 4 weeks
• Min batch size: 200 kits, max batch size: 1,000 kits
• Production frequency: every 2 weeks
• Safety stock: Global, 15% overage, 10% site seed
• Custom lot: "Initial Supply" with 300 Kit A units, manufacture Jan 1, ship Jan 15

What happens in the forecast:

1. Demand curve: Enrollment peaks in February to March, with follow-up visits extending through September.
2. Initial supply: The custom lot provides 300 Kit A units available from Jan 15, covering approximately the first 2 months of Kit A demand.
3. Safety stock buffer: 15% overage means the system plans for approximately 1,035 total kits instead of 900. The 10% site seed pre-distributes approximately 104 kits to sites before enrollment starts.
4. Production scheduling: With a 4-week lead time and 2-week production frequency, orders must be placed 4 weeks before kits are needed, new runs can be initiated every 2 weeks, and each run produces between 200 and 1,000 kits.
5. Batch rounding: If demand for a period is 350 kits, the system orders 400 (rounded up given the minimum of 200).

Validation Requirements

To proceed to Step 8, all fields must pass strict validation:

The Continue button is enabled only when all validations pass.

Tips

• Start with global safety stock. Unless you have specific requirements per country or depot, begin with global mode. You can switch later as your trial plan evolves.
• Manufacturing lead time is your most critical setting. A longer lead time means more inventory holding and earlier order placement. Shorter lead times directly reduce supply risk.
• Batch size impacts cost and waste. Larger minimum batches are often cheaper per unit but produce more surplus. If your kits have short shelf lives, smaller batches reduce expiry waste.
• Use custom lots for confirmed supply. Enter confirmed manufacturing batches, especially for initial supply, to give the forecast accurate starting inventory.
• Watch for capacity warnings in analytics. If the forecast shows yellow or red risk indicators, your production constraints may be creating supply risk. Work with your manufacturer to increase capacity or adjust recruitment timelines.
• This is the final configuration step before analytics. Once you proceed past production constraints, Prognosis has everything it needs to calculate the complete supply plan. You can always return to edit these settings.