Table 1.
Definitions of major placebo reactions (MPR) at DBPCFC with examples
| Type of major placebo reaction (MPR) | Definition according to signs or symptoms elicited by placebo challenge meal | Example for reaction elicited by placebo challenge meal Dose level/VASplacebo | Example for reaction elicited by Soy challenge meal Dose level/VAS |
|---|---|---|---|
| Objective | Any ObjS (O1-10, attributable to the DBPCFC) | Any | Any or none |
| Any ObjS (O1-10, not clear if being attributable to the DBPCFC i.e. single wheal) at a lower dose level compared to soy |
5 or below | 6 | |
| Subjective | Any single SubjS* (S1–8) at lower dose level compared to soy | 5 or below/any VASplacebo * | 6/any VASsoy * |
| Single* | Any single SubjS* (S1–8) at same dose level like any single SubjS* to soy | 5/any VASplacebo * | 5/any VASsoy * |
| Single** | Any single SubjS** (S1–8) at same dose level like any single SubjS to soy and no difference of at least 2 cm in favor of soy | 4/any VASplacebo ** (e.g. 0.6 cm) |
4/any VASsoy *** < VAS*** placebo -2 cm (e.g. 2 cm) |
| Sum type*** | Two or more aggregated SubjS** (S1–10) and two or more aggregated SubjS** (S1–8) to soy (any but same dose level for both) and no difference between sum VAS values of at least 2 cm in favor of soy |
5/any sum VASplacebo *** (e.g. 4 cm) |
5/any sum VASsoy *** < sum VASplacebo ***-2 cm (e.g. 5 cm) |
ObjS objective signs, SubjS subjective symptoms, VAS soy /VAS placebo visual analogue scale value at soy/placebo challenge in cm
* Single VAS of at least 1.5 cm
** Single VAS of at least 0.5 cm
*** Sum of VAS values of at least 0.5 cm, e.g.—example given