ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12618001762246p

Ethics application status

Not yet submitted

Date submitted

21/10/2018

Date registered

25/10/2018

Date last updated

25/10/2018

Type of registration

Prospectively registered

Titles & IDs

Public title

Pregabalin versus gabapentin in chronic neuropathic pain

Scientific title

A pilot series of n-of-1 randomised controlled trials to compare pregabalin and gabapentin in persistent neuropathic pain.

Secondary ID [1]

None

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Chronic neuropathic pain

Condition category

Condition code

Anaesthesiology

Pain management

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Participants will undergo a 12-week trial comprising three 4-week treatment cycles. Each cycle will consist of a 2-week gabapentin block and a 2-week pregabalin block in an individually randomised order. During each block, participants will take their respective medication orally three times daily, with doses derived from the participant's existing neuropathic pain treatment dose. Throughout the trial, participants will complete a daily patient diary, reporting on relevant neuropathic pain symptoms such as daily pain, sleep interference, and functional limitation.

At the end of each block, participants will return their unused medications and finished patient diaries. After the 12-week trial, participants will complete a review appointment with their treating physician, in which the results of the trial will be presented to facilitate an informed and long-term treatment decision. Participants and physicians will additionally provide feedback on their experiences with the trial, as well as suggestions for further improvement.

Intervention code [1]

Treatment: Drugs

Comparator / control treatment

In this trial, pregabalin will be compared against gabapentin in individual patients with neuropathic pain. There is no explicit control.

Control group

Active

Outcomes

Primary outcome [1]

Difference in average pain intensity over the last 24 hours between each treatment block, as measured on a Visual Analogue Scale

Timepoint [1]

At the end of each 4-week treatment cycle and at the end of the 12-week trial

Secondary outcome [1]

Difference in sleep interference due to pain between each treatment block, as measured on a Visual Analogue Scale

Timepoint [1]

At the end of each 4-week treatment cycle and at the end of the 12-week trial

Secondary outcome [2]

Difference in functional ability between each treatment block, as measured by the Patient-Specific Function Scale

Timepoint [2]

At the end of each 4-week treatment cycle and at the end of the 12-week trial

Secondary outcome [3]

Difference in mental state between each treatment block, as measured by the Depression Anxiety Stress Scale 21

Timepoint [3]

At the end of each 4-week treatment cycle and at the end of the 12-week trial

Secondary outcome [4]

Patient's final medication preference (either pregabalin or gabapentin), as measured in binary form during the end-of-trial review

Timepoint [4]

At the end of the 12-week trial

Secondary outcome [5]

Feasibility composite outcome::
1) Enrolment rate, measured as participants enrolled per month
2) Proportion of screened patients able to be recruited for full trial
3) Patient compliance, assessed via unused medication counts and diary completion rates
4) Qualitative feedback regarding trial logistics and overall patient satisfaction, as collected from the patient and physician transcript during the end-of-trial review

Timepoint [5]

At the end of the 12-week trial

Eligibility

Key inclusion criteria

1. Existing patient at Port Kembla Hospital
2. Age 18 years or greater
3. Existing diagnosis of chronic and stable neuropathic pain.
4. Currently prescribed gabapentin for neuropathic pain.
5. Willingness to maintain pain medications and treatments throughout the trial.
6. Capable English speaker
7. Able to be reliably contacted by telephone.

Minimum age

18 Years

Maximum age

No limit

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

1. Currently breastfeeding or pregnant
2. Gabapentin or pregabalin allergy or intolerance
3. Active or past history of seizures
4. Creatinine clearance under 30 mL/min.
5. Likelihood of surgery during the trial
6. Inability to attend review visits

Study design

Purpose of the study

Treatment

Allocation to intervention

Non-randomised trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Block randomization, with a block size of 2, will be used to generate random sequences for allocation to recruited participants. Randomization will be conducted by a statistician from the University of Queensland.

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people receiving the treatment/s
The people administering the treatment/s

Intervention assignment

Crossover

Other design features

Phase

Type of endpoint/s

Safety/efficacy

Statistical methods / analysis

Appropriate statistical analyses will be used to evaluate individual N-of-1 trial data. Data will also be aggregated from all trials to facilitate a meta-analysis of pregabalin versus gabapentin for neuropathic pain.

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

1/01/2019

Actual

Date of last participant enrolment

Anticipated

Actual

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

QLD

Recruitment hospital [1]

Port Kembla Hospital - Warrawong

Recruitment postcode(s) [1]

2502 - Warrawong

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

Department of Rehabilitation Medicine, Port Kembla Hospital

Address [1]

89-91 Cowper St, Warrawong, New South Wales 2502

Country [1]

Australia

Primary sponsor type

Hospital

Name

Department of Rehabilitation Medicine Port Kembla Hospital

Address

89-91 Cowper St, Warrawong, New South Wales 2502

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Not yet submitted

Ethics committee name [1]

Ethics committee address [1]

Ethics committee country [1]

Date submitted for ethics approval [1]

01/01/2019

Approval date [1]

Ethics approval number [1]

Summary

Brief summary

Pregabalin and gabapentin are two medications commonly used to treat neuropathic pain. While both are moderately effective, there is significant variation between individuals, with patients often responding to one medication but not the other. N-of-1 trials are clinical trials that study a single patient, facilitating personalized data collection and reporting. We hypothesize that N-of-1 trials are a feasible method of comparing between pregabalin and gabapentin for individual patients with neuropathic pain.

Trial website

Trial related presentations / publications

Public notes

Gabapentin and Pregabalin are commonly used medications for neuropathic pain.  They have similar mechanisms of action and adverse effects. In the Australian public health system, a significant cost differential exists between the two, with pregabalin being more expensive. The Illawarra-Shoalhaven Chronic Pain Service (I-SCPS) adopted strict open label prescribing  criteria to limit Pregabalin to a second line medication, but this failed to prevent a rapid expansion in use. Head-to-head scientific evidence on this issue is of poor quality and contradictory. NICE recommendations for pregabalin use as first line are based on costings that are European based and dated.  The local drug committee sought reassurance from the I-SCPS that clinical benefits were accruing from expenditure on Pregabalin over Gabapentin in individuals with neuropathic pain.

N-of-1 trials are randomized, double blind, multiple crossover trials in an individual patient. They help control for placebo effects, secondary effects, natural history, expectations of patients and clinicians, and the interactions of uncontrolled interventions such as over-the-counter medications in making a precise clinical decisions.

Contacts

Principal investigator

Name

Dr Jane Nikles

Address

University of Queensland Centre for Clinical Research
Building 71/918 RBWH Herston
Brisbane City QLD 4029

Country

Australia

Phone

+61 7 3374 3898

Fax

catherine.nikles@uq.edu.au

Contact person for public queries

Name

Jane Nikles

Address

University of Queensland Centre for Clinical Research
Building 71/918 RBWH Herston
Brisbane City QLD 4029

Country

Australia

Phone

+61 7 3374 3898

Fax

catherine.nikles@uq.edu.au

Contact person for scientific queries

Name

Jane Nikles

Address

University of Queensland Centre for Clinical Research
Building 71/918 RBWH Herston
Brisbane City QLD 4029

Country

Australia

Phone

+61 7 3374 3898

Fax

catherine.nikles@uq.edu.au

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Comparing pregabalin and gabapentin for persistent neuropathic pain: A protocol for a pilot N-of-1 trial series.	2021	https://dx.doi.org/10.1016/j.conctc.2021.100852

N.B. These documents automatically identified may not have been verified by the study sponsor.

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Documents added manually

Documents added automatically