Pruritus
Conditions
Keywords
Itch, Botox, Healthy Volunteers
Brief summary
The purpose of this study is to determine if Botox is effective in the treatment of an experimentally induced itch that mimics chronic itch in healthy volunteers.
Detailed description
Several studies have shown that botulinum toxin type A (BoNT/A) has an antipruritic effect due to the inhibition of acetylcholine and other pruritic factors, such as substance P and glutamate. For instance, subcutaneous BoNT/A improves itch accompanied to hand eczema, dermatitis, lichen simplex, and rhinitis. Furthermore, a double-blind, placebo-controlled study showed that BoNT/A reduced histamine itch intensity in healthy men. Since acetylcholine has been shown to mediate itch in atopic dermatitis, this study aims to test the itch relieving effect of BoNT/A on a non-histaminergic model for chronic itch. This non-histaminergic model using the plant cowhage induces itch by activating protease activated receptor 2 (PAR2) receptors, which play a role in the itch of atopic dermatitis, also making this model better suited to test the efficacy of BoNT/A to relive chronic itch.
Interventions
DRUGBotox
10 units of Botox will be intradermally injected into one 4x4cm area on the volar forearm on 1st study visit.
DRUGSaline
10 units of the Saline vehicle will be intradermally injected into one 4x4cm area on the contralateral volar forearm on the 1st study visit.
Sponsors
Allergan
Temple University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
1. Healthy volunteers between 18 and 50 years of age. 2. Must be in general good health with no disease or physical conditions that would impair evaluation of itch and pain perception. 3. No history of chronic itch or pain. 4. Must abstain from the use of any systemic or topical anti-histamine, steroid, or pain relief medications from the week prior to the study till the completion of the study. 5. Must abstain from the use of moisturizers on the arm.
Exclusion criteria
1. Individuals under 18 or over 50 years of age. 2. Inability to complete the required measures. 3. The presence of an itchy skin disease. 4. Diagnosis of diseased that would affect itch or pain perception (e.g. neuropathies). 5. Currently enrolled in any investigational study in which the subject is receiving any type of drug, biological, or non-drug therapy. 6. Use of oral, topical analgesics, or other medications known to interfere with itch or pain perception in the week prior to the study and throughout the study (e.g. antihistamines, anesthetics, opioids, neuroleptics, etc.). 7. Use of emollients on the arms a week prior to the study and throughout the study. 8. Use of anti-depressants, anti-psychotics, and illicit drugs. 9. Known history of neuropathy, uremia, uncontrolled thyroid disease, and diabetes mellitus. 10. Use of Botulinum toxin in the last year. 11. Known allergies to Botox. 12. Pregnant women. (Women of child bearing potential will undergo an human chorionic gonadotrophin (hCG) pregnancy test before Botox application). 13. Hypersensitivity to any botulinum toxin preparation or to any of the components in the formulation. 14. Infection at the injection site. 15. Cardiovascular disease. 16. Neuromuscular disorder (e.g., amyotrophic lateral sclerosis, myasthenia gravis, or Lambert-Eaton syndrome). 17. Compromised respiratory function. 18. Dysphagia. 19. History of urinary tract infection. 20. History of urinary retention.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1) | The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage. |
| Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 week from Baseline | The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage. |
| Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month from Baseline | The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage. |
| Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months from Baseline | The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | Baseline, 1 week, 1 month, 3 months | A secondary endpoint is to see if Botox has a relieving effect on heat pain using a pain visual analog scale (VAS) intensity scale as an outcome measure. The pain VAS intensity scale ranges from a minimum of 0 (no pain - best) to a maximum of 10 (maximum pain - worst). Participants will rate pain intensity after pain is induced with a heat thermode. |
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Botox and Saline Vehicle Control 10 units of both Botox and a saline vehicle will be intradermally injected into one forearm or the other on the first study visit. The subject will be blinded to which forearm receives the Botox and which forearm receives the saline vehicle.
Botox: 10 units of Botox will be intradermally injected into one 4x4cm area on the volar forearm on 1st study visit.
Saline: 10 units of the Saline vehicle will be intradermally injected into one 4x4cm area on the contralateral volar forearm on the 1st study visit. | 35 |
| Total | 35 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Lost to Follow-up | 1 |
Baseline characteristics
| Characteristic | Botox and Saline Vehicle Control |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 35 Participants |
| Age, Continuous | 26.8 years STANDARD_DEVIATION 6.8 |
| Region of Enrollment United States | 35 participants |
| Sex: Female, Male Female | 19 Participants |
| Sex: Female, Male Male | 16 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 35 | 0 / 35 |
| serious Total, serious adverse events | 0 / 35 | 0 / 35 |
Outcome results
Primary
Itch by VAS Itch Intensity at 1 Month (Visit 3)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: 1 Month from Baseline
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 30 seconds | 5.0 units on a scale | Standard Deviation 2.6 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 180 seconds | 1.5 units on a scale | Standard Deviation 1.4 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 90 seconds | 4.3 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 0 seconds | 3.2 units on a scale | Standard Deviation 2.6 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 240 seconds | 0.7 units on a scale | Standard Deviation 1 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 120 seconds | 3.5 units on a scale | Standard Deviation 2 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 270 seconds | 0.3 units on a scale | Standard Deviation 0.7 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 60 seconds | 5.1 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 300 seconds | 0.2 units on a scale | Standard Deviation 0.5 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 150 seconds | 2.3 units on a scale | Standard Deviation 1.8 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), All Times | 2.5 units on a scale | Standard Deviation 2.5 |
| Botox | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 210 seconds | 0.9 units on a scale | Standard Deviation 1.3 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), All Times | 3.2 units on a scale | Standard Deviation 2.9 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 0 seconds | 3.8 units on a scale | Standard Deviation 2.8 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 30 seconds | 6.2 units on a scale | Standard Deviation 2.4 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 60 seconds | 6.2 units on a scale | Standard Deviation 1.8 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 90 seconds | 5.7 units on a scale | Standard Deviation 2.3 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 120 seconds | 4.5 units on a scale | Standard Deviation 2.4 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 150 seconds | 3.3 units on a scale | Standard Deviation 2.2 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 180 seconds | 2.2 units on a scale | Standard Deviation 2.1 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 210 seconds | 1.4 units on a scale | Standard Deviation 1.7 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 240 seconds | 0.9 units on a scale | Standard Deviation 1.3 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 270 seconds | 0.6 units on a scale | Standard Deviation 1 |
| Saline | Itch by VAS Itch Intensity at 1 Month (Visit 3) | 1 Month (Visit 3), 300 seconds | 0.4 units on a scale | Standard Deviation 0.8 |
Comparison: 1 month (Visit 3) was the second assessment of itch VAS after itch induction after Botox or saline application. Analyzed using ANOVA with repeated measures to compare main effects of treatment (Botox vs saline) and time, and interaction effect between treatment and time.p-value: <0.0001ANOVA with Repeated Measures
Primary
Itch by VAS Itch Intensity at 1 Week (Visit 2)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: 1 week from Baseline
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 120 seconds | 3.7 units on a scale | Standard Deviation 2.4 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 0 seconds | 3.3 units on a scale | Standard Deviation 2.4 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 30 seconds | 5.4 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 60 seconds | 5.9 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 90 seconds | 4.9 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 150 seconds | 2.7 units on a scale | Standard Deviation 2.5 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 180 seconds | 2.0 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 210 seconds | 1.4 units on a scale | Standard Deviation 1.8 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 240 seconds | 0.9 units on a scale | Standard Deviation 1.5 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 270 seconds | 0.6 units on a scale | Standard Deviation 1.3 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 300 seconds | 0.4 units on a scale | Standard Deviation 1.1 |
| Botox | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), All Times | 2.8 units on a scale | Standard Deviation 2.8 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 300 seconds | 0.7 units on a scale | Standard Deviation 1.3 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 180 seconds | 2.7 units on a scale | Standard Deviation 2.1 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 0 seconds | 4.0 units on a scale | Standard Deviation 2.9 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 270 seconds | 0.9 units on a scale | Standard Deviation 1.3 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 30 seconds | 6.7 units on a scale | Standard Deviation 2.2 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 210 seconds | 1.9 units on a scale | Standard Deviation 1.9 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 60 seconds | 6.9 units on a scale | Standard Deviation 2.1 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), All Times | 3.6 units on a scale | Standard Deviation 2.9 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 90 seconds | 6.1 units on a scale | Standard Deviation 1.7 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 120 seconds | 4.8 units on a scale | Standard Deviation 2 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 240 seconds | 1.3 units on a scale | Standard Deviation 1.6 |
| Saline | Itch by VAS Itch Intensity at 1 Week (Visit 2) | 1 Week (Visit 2), 150 seconds | 3.8 units on a scale | Standard Deviation 2.2 |
Comparison: 1 week (Visit 2) was the first assessment of itch VAS after itch induction after Botox or saline application. Analyzed using ANOVA with repeated measures to compare main effects of treatment (Botox vs saline) and time, and interaction effect between treatment and time.p-value: <0.0001ANOVA with Repeated Measures
Primary
Itch by VAS Itch Intensity at 3 Months (Visit 4)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: 3 Months from Baseline
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 0 seconds | 2.3 units on a scale | Standard Deviation 1.8 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 30 seconds | 4.5 units on a scale | Standard Deviation 2.5 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 60 seconds | 4.9 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 90 seconds | 4.6 units on a scale | Standard Deviation 2.3 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 120 seconds | 3.8 units on a scale | Standard Deviation 2 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 150 seconds | 3.0 units on a scale | Standard Deviation 2 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 180 seconds | 2.1 units on a scale | Standard Deviation 1.9 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 210 seconds | 1.5 units on a scale | Standard Deviation 1.7 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 240 seconds | 1.0 units on a scale | Standard Deviation 1.2 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 270 seconds | 0.7 units on a scale | Standard Deviation 1.1 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 300 seconds | 0.3 units on a scale | Standard Deviation 0.6 |
| Botox | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), All Times | 2.6 units on a scale | Standard Deviation 2.4 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 300 seconds | 0.6 units on a scale | Standard Deviation 1.1 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 0 seconds | 3.3 units on a scale | Standard Deviation 2.4 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 180 seconds | 2.8 units on a scale | Standard Deviation 1.9 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 30 seconds | 5.4 units on a scale | Standard Deviation 2.5 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 270 seconds | 0.9 units on a scale | Standard Deviation 1.4 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 60 seconds | 5.9 units on a scale | Standard Deviation 2.2 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 210 seconds | 1.9 units on a scale | Standard Deviation 1.9 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 90 seconds | 5.2 units on a scale | Standard Deviation 2.1 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), All Times | 3.2 units on a scale | Standard Deviation 2.7 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 120 seconds | 4.7 units on a scale | Standard Deviation 2.1 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 240 seconds | 1.4 units on a scale | Standard Deviation 1.6 |
| Saline | Itch by VAS Itch Intensity at 3 Months (Visit 4) | 3 Months (Visit 4), 150 seconds | 3.6 units on a scale | Standard Deviation 2.1 |
Comparison: 3 months (Visit 4) was the third assessment of itch VAS after itch induction after Botox or saline application. Analyzed using ANOVA with repeated measures to compare main effects of treatment (Botox vs saline) and time, and interaction effect between treatment and time.p-value: 0.0004ANOVA with Repeated Measures
Primary
Itch by VAS Itch Intensity at Baseline (Visit 1)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: Baseline (Visit 1)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 0 seconds | 4.5 units on a scale | Standard Deviation 2.8 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 30 seconds | 6.5 units on a scale | Standard Deviation 2.6 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 60 seconds | 6.8 units on a scale | Standard Deviation 2.2 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 90 seconds | 5.9 units on a scale | Standard Deviation 2.1 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 120 seconds | 5.1 units on a scale | Standard Deviation 2.2 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 150 seconds | 4.1 units on a scale | Standard Deviation 2.2 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 180 seconds | 2.8 units on a scale | Standard Deviation 2 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 210 seconds | 2.0 units on a scale | Standard Deviation 1.6 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 240 seconds | 1.3 units on a scale | Standard Deviation 1.5 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 270 seconds | 0.9 units on a scale | Standard Deviation 1.3 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 300 seconds | 0.6 units on a scale | Standard Deviation 1.1 |
| Botox | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), All Times | 3.7 units on a scale | Standard Deviation 3 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 300 seconds | 0.9 units on a scale | Standard Deviation 1.5 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 0 seconds | 4.3 units on a scale | Standard Deviation 2.8 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 180 seconds | 2.8 units on a scale | Standard Deviation 1.8 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 30 seconds | 6.3 units on a scale | Standard Deviation 2.3 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 270 seconds | 0.9 units on a scale | Standard Deviation 1.6 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 60 seconds | 6.5 units on a scale | Standard Deviation 2.1 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 210 seconds | 2.0 units on a scale | Standard Deviation 1.8 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 90 seconds | 6.3 units on a scale | Standard Deviation 1.5 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), All Times | 3.7 units on a scale | Standard Deviation 2.9 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 120 seconds | 5.1 units on a scale | Standard Deviation 2 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 240 seconds | 1.4 units on a scale | Standard Deviation 1.7 |
| Saline | Itch by VAS Itch Intensity at Baseline (Visit 1) | Baseline (Visit 1), 150 seconds | 3.9 units on a scale | Standard Deviation 2.1 |
Comparison: Baseline assessment of itch VAS after itch induction but prior to Botox or saline application. Analyzed using ANOVA with repeated measures to compare main effects of treatment (Botox vs saline) and time, and interaction effect between treatment and time.p-value: 0.9704ANOVA with Repeated Measures
Secondary
Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment
A secondary endpoint is to see if Botox has a relieving effect on heat pain using a pain visual analog scale (VAS) intensity scale as an outcome measure. The pain VAS intensity scale ranges from a minimum of 0 (no pain - best) to a maximum of 10 (maximum pain - worst). Participants will rate pain intensity after pain is induced with a heat thermode.
Time frame: Baseline, 1 week, 1 month, 3 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Botox | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | 1 Week | 3.7 units on a scale | Standard Deviation 2.5 |
| Botox | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | 3 Months | 4.1 units on a scale | Standard Deviation 2.4 |
| Botox | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | 1 Month | 3.7 units on a scale | Standard Deviation 2.5 |
| Botox | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | All Visits | 3.8 units on a scale | Standard Deviation 2.4 |
| Botox | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | Baseline | 3.6 units on a scale | Standard Deviation 2.4 |
| Saline | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | All Visits | 4.0 units on a scale | Standard Deviation 2.4 |
| Saline | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | Baseline | 3.7 units on a scale | Standard Deviation 2.2 |
| Saline | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | 1 Week | 3.7 units on a scale | Standard Deviation 2.5 |
| Saline | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | 1 Month | 4.1 units on a scale | Standard Deviation 2.6 |
| Saline | Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment | 3 Months | 4.3 units on a scale | Standard Deviation 2.5 |
Comparison: Analyzed using ANOVA with repeated measures to compare main effects of treatment (Botox vs saline) and visit, and interaction effect between treatment and visit.p-value: 0.1306ANOVA with Repeated Measures