Title

Oral LAT8881 in Neuropathic Pain
A Phase IIa Study of the Efficacy and Safety of Oral LAT8881 in Neuropathic Pain
  • Phase

    Phase 2
  • Study Type

    Interventional
  • Intervention/Treatment

    LAT8881 ...
  • Study Participants

    53
This is a randomised, placebo-controlled, double-blind, crossover, phase IIa study to investigate the efficacy and safety of oral LAT8881 in neuropathic pain.
This is a randomised, placebo-controlled, double-blind, crossover, phase IIa study to investigate the efficacy and safety of oral LAT8881 in neuropathic pain. After a one week baseline period, subjects entered into the study will be randomised to receive Investigational Medicinal Product (IMP) (LAT8881 or placebo) twice daily for four weeks.

The first treatment period will be followed by a washout period of two weeks and then a second baseline period of one week. Subjects will not take any IMP over these three weeks.

After the second baseline period, subjects will cross over to receive the second treatment (either LAT8881 or placebo, whichever treatment was not received in the first treatment period) twice daily for four weeks.

The pharmacokinetics (PK) of LAT8881 will be investigated in 15 subjects (PK subjects) at selected Australian sites.
Study Started
Apr 09
2019
Primary Completion
Apr 19
2020
Study Completion
May 03
2020
Results Posted
Apr 23
2021
Last Update
Jun 14
2021

Drug LAT8881

LAT8881 oral capsule

Drug Placebo

Placebo oral capsule

LAT8881 Active Comparator

1 x 30 mg capsule of LAT8881 taken by mouth, twice daily (morning and evening) during the four-week treatment period.

Placebo Placebo Comparator

1 x 30 mg capsule of placebo, taken by mouth, twice daily (morning and evening) during the four-week treatment period.

Criteria

Inclusion Criteria:

Clinical diagnosis of post herpetic neuralgia, with pain persisting for at least 3 months after the onset of herpes zoster rash OR

Clinical diagnosis of distal painful polyneuropathy due to Type I or Type II diabetes mellitus with:

symmetrical, bilateral pain in the lower extremities for at least 3 months and
diabetes under control for at least 3 months prior to randomisation, as indicated by a glycated haemoglobin level (HbA1c) of ≤ 11% (97 mmol/mol) and on a stable dose of insulin or oral diabetic medication for 3 months prior to screening, and
no change in diabetic medication planned for the duration of the study

Positive sensory symptoms (mechanical or thermal) associated with neuropathic pain, confirmed by:

painDETECT questionnaire (PD-Q) and
Clinical assessment, showing signs of neuropathic pain in either a dermatomal (PHN) or distal symmetrical distribution (DPN)

8. An average daily pain score on the numeric pain rating scale (NPRS) of at least 4 and no more than 8 in the last five diary entries before randomisation

Exclusion Criteria:

Presence of moderate to severe pain from other causes that may confound assessment or self-evaluation of NP.
Subjects with both DPN and PHN

Summary

LAT8881

Placebo

All Events

Event Type Organ System Event Term LAT8881 Placebo

Absolute Change in Mean Pain Score, Using an 11 Point Numeric Pain Rating Scale (NPRS)

The 11-point numeric pain rating scale (NPRS) ranges from 0 ("no pain") to 10 ("worst pain imaginable"). A larger negative number represents a greater reduction in pain. The efficacy of oral LAT8881 in neuropathic pain was compared with placebo, when assessed by change in mean pain intensity scores, using this 11 point numeric pain rating scale.

LAT8881

-0.87
score on a scale (Mean)
Standard Deviation: 1.53

Placebo

-0.74
score on a scale (Mean)
Standard Deviation: 2.09

Change in NPRS Score After the First and Last Dose of LAT8881 and Placebo

To investigate the effect of oral LAT8881 in neuropathic pain compared with placebo, as measured by the numeric pain rating score (NPRS). The 11-point numeric pain rating scale ranges from 0 ("no pain") to 10 ("worst pain imaginable"). A larger negative number represents a greater reduction in pain. This outcome was investigated only in the pharmacokinetic subset of per protocol subjects.

LAT8881

Absolute baseline score, first dose

4.5
score on a scale (Mean)
Standard Deviation: 2.2

Absolute baseline score, last dosing day

4.4
score on a scale (Mean)
Standard Deviation: 2.2

Change from baseline, 0.5 hours after first dose

-0.1
score on a scale (Mean)
Standard Deviation: 0.77

Change from baseline, 0.5 hours after last dose

-0.6
score on a scale (Mean)
Standard Deviation: 2.43

Change from baseline, 1 hour after first dose

-0.4
score on a scale (Mean)
Standard Deviation: 0.63

Change from baseline, 1 hour after last dose

-0.5
score on a scale (Mean)
Standard Deviation: 2.58

Change from baseline, 2 hours after first dose

-0.1
score on a scale (Mean)
Standard Deviation: 0.95

Change from baseline, 2 hours after last dose

-0.8
score on a scale (Mean)
Standard Deviation: 2.19

Change from baseline, 4 hours after first dose

0.1
score on a scale (Mean)
Standard Deviation: 1.07

Change from baseline, 4 hours after last dose

-0.5
score on a scale (Mean)
Standard Deviation: 2.26

Change from baseline, 6 hours after first dose

Change from baseline, 6 hours after last dose

-0.7
score on a scale (Mean)
Standard Deviation: 1.93

Placebo

Absolute baseline score, first dose

4.8
score on a scale (Mean)
Standard Deviation: 1.9

Absolute baseline score, last dosing day

4.0
score on a scale (Mean)
Standard Deviation: 2.2

Change from baseline, 0.5 hours after first dose

-0.2
score on a scale (Mean)
Standard Deviation: 1.53

Change from baseline, 0.5 hours after last dose

-0.4
score on a scale (Mean)
Standard Deviation: 0.84

Change from baseline, 1 hour after first dose

-0.6
score on a scale (Mean)
Standard Deviation: 1.95

Change from baseline, 1 hour after last dose

-0.4
score on a scale (Mean)
Standard Deviation: 1.02

Change from baseline, 2 hours after first dose

-0.8
score on a scale (Mean)
Standard Deviation: 2.26

Change from baseline, 2 hours after last dose

-0.1
score on a scale (Mean)
Standard Deviation: 0.77

Change from baseline, 4 hours after first dose

-0.6
score on a scale (Mean)
Standard Deviation: 2.17

Change from baseline, 4 hours after last dose

-0.4
score on a scale (Mean)
Standard Deviation: 0.93

Change from baseline, 6 hours after first dose

-0.7
score on a scale (Mean)
Standard Deviation: 1.77

Change from baseline, 6 hours after last dose

-0.4
score on a scale (Mean)
Standard Deviation: 0.84

Change in Mean Pain Scores After 1, 2 and 3 Weeks of Treatment, Using NPRS

To investigate the effect of oral LAT8881 on mean pain scores in neuropathic pain compared with placebo, as measured by the numeric pain rating scale (NPRS). The 11-point numeric pain rating scale ranges from 0 ("no pain") to 10 ("worst pain imaginable"). A larger negative number represents a greater reduction in pain.

LAT8881

Baseline

6.18
units on a scale (Mean)
Standard Deviation: 1.53

Change from baseline at Week 1

-0.5
units on a scale (Mean)
Standard Deviation: 1.37

Change from baseline at Week 2

-0.73
units on a scale (Mean)
Standard Deviation: 1.49

Change from baseline at Week 3

-0.84
units on a scale (Mean)
Standard Deviation: 1.61

Placebo

Baseline

6.18
units on a scale (Mean)
Standard Deviation: 1.45

Change from baseline at Week 1

-0.55
units on a scale (Mean)
Standard Deviation: 1.27

Change from baseline at Week 2

-0.91
units on a scale (Mean)
Standard Deviation: 1.62

Change from baseline at Week 3

-0.84
units on a scale (Mean)
Standard Deviation: 1.88

30% Responder Rate in Oral LAT8881 Compared With Placebo, as Assessed by the Numeric Pain Rating Scale.

To determine the proportion of subjects with at least a 30% reduction in mean NPRS after 4 weeks treatment. The 11-point numeric pain rating scale (NPRS) ranges from 0 ("no pain") to 10 ("worst pain imaginable"). A decrease in pain score represents an improvement in pain.

LAT8881

Placebo

50% Responder Rate in Oral LAT8881 Compared With Placebo, as Assessed by the Numeric Pain Rating Scale.

To determine the proportion of subjects with at least a 50% reduction in mean the numeric pain rating scale (NPRS) after 4 weeks treatment. The 11-point numeric pain rating scale ranges from 0 ("no pain") to 10 ("worst pain imaginable"). A decrease in pain score represents an improvement in pain.

LAT8881

Placebo

Maximum Change in Mean NPRS

To determine the maximum effects of oral LAT8881 in neuropathic pain, compared with placebo, as measured by the numeric pain rating scale (NPRS). The 11-point numeric pain rating scale ranges from 0 ("no pain") to 10 ("worst pain imaginable"). A larger negative number represents a greater reduction in pain..

LAT8881

-1.53
score on a scale (Mean)
Standard Deviation: 1.37

Placebo

-1.55
score on a scale (Mean)
Standard Deviation: 1.41

Change in Functioning as Assessed by the Brief Pain Inventory Interference Scale (BPI)

To evaluate the effects of oral LAT8881, compared with placebo, on functioning when measured by the Brief Pain Inventory Interference Scale (BPI). The BPI assesses the severity of pain and its impact on functioning. Patients are asked to assess the level of interference experienced across seven items; general activity, mood, walking ability, normal work, relations with other people, sleep and enjoyment of life, with a "0" meaning "no interference, and a "10", at the top end of the scale, meaning "complete interference". The result is the mean of the score of the seven items. A reduction in mean score indicates a decrease in interference.

LAT8881

Baseline BPI

4.71
score on a scale (Mean)
Standard Deviation: 2.45

Change from baseline

-0.57
score on a scale (Mean)
Standard Deviation: 1.83

Placebo

Baseline BPI

4.91
score on a scale (Mean)
Standard Deviation: 2.32

Change from baseline

-1.12
score on a scale (Mean)
Standard Deviation: 1.97

Change in Pain Characteristics and Intensity, as Assessed by the Short Form McGill Pain Questionnaire (SF-MPQ-2)

To evaluate the effect of oral LAT8881, compared with placebo, on pain symptoms in subjects with neuropathic pain, when measured by the Short Form McGill Pain Questionnaire (SF-MPQ-2). The SF-MPQ-2 contains 22 descriptors of pain and related symptoms, each scored from "0" (none) to "10" (worst possible). The scores for each descriptor at each visit are averaged to give a mean score from 0 to 10. A larger negative number represents a greater reduction in pain.

LAT8881

Baseline SF-MPQ-2

3.88
score on a scale (Mean)
Standard Deviation: 1.81

Change from baseline

-0.66
score on a scale (Mean)
Standard Deviation: 1.34

Placebo

Baseline SF-MPQ-2

3.86
score on a scale (Mean)
Standard Deviation: 1.73

Change from baseline

-0.63
score on a scale (Mean)
Standard Deviation: 1.70

Change in Neuropathic Pain Symptoms, as Assessed by Neuropathic Pain Symptom Inventory (NPSI)

The Neuropathic Pain Symptom Inventory (NPSI) contains ten items related to different pain descriptors (e.g. burning, squeezing, electric-shock, stabbing, tingling), allowing the assessment of the different dimensions of neuropathic pain, and two items related to the frequency and duration of pain. Each pain descriptor is rated on an 11-point numeric rating scale from 0 (no pain) to 10 (worst imaginable pain). Total pain intensity score is calculated by the sum of the 10 descriptors and can range from 0 to 100. A higher score indicates a higher pain intensity. A larger negative number represents a greater reduction in pain.

LAT8881

Baseline NPSI

40.7
score on a scale (Mean)
Standard Deviation: 17.2

Change from baseline

-6.0
score on a scale (Mean)
Standard Deviation: 14.5

Placebo

Baseline NPSI

41.1
score on a scale (Mean)
Standard Deviation: 16.2

Change from baseline

-7.4
score on a scale (Mean)
Standard Deviation: 16.9

Change in Emotional Functioning, as Assessed by the Beck Depression Inventory-II

To evaluate the effect of oral LAT8881, compared with placebo, on emotional functioning when measured by the Beck Depression Inventory-II (BDI-II). The BDI-II consists of 21 items; each item is a list of four statements arranged in order of increasing severity about a particular symptom of depression. Each statement is scored from 0 to 3. Each of the 21 items is summed to give a single score for the BDI-II. Scores can range from 0 (no depression) to 63 (severe depression). An increase from baseline to the end of treatment indicates a deterioration.

LAT8881

Baseline BDI-II

11.3
score on a scale (Mean)
Standard Deviation: 8.6

Change from baseline

-1.1
score on a scale (Mean)
Standard Deviation: 4.14

Placebo

Baseline BDI-II

12.1
score on a scale (Mean)
Standard Deviation: 9.3

Change from baseline

-1.2
score on a scale (Mean)
Standard Deviation: 7.98

Patient Global Impression of Change Score

The Patient Global Impression of Change (PGIC) is a a single-item rating by subjects of their improvement with treatment during a clinical trial. It asks the subject to rate their improvement with therapy on a 7-point scale, ranging from substantially worse ("0") to substantially improved ("7"), with no change ("4") as the mid-point. A score above 4 indicates an improvement.

LAT8881

4.5
score on a scale (Mean)
Standard Deviation: 1.23

Placebo

4.8
score on a scale (Mean)
Standard Deviation: 1.33

Rescue Medication Use

To determine the change from baseline in paracetamol rescue medication use during oral LAT8881 administration, compared with placebo.

LAT8881

Week 1

Week 2

Week 3

Week 4

Placebo

Week 1

Week 2

Week 3

Week 4

Maximum Plasma Concentration of LAT8881 (Cmax) After Oral LAT8881

Cmax is calculated after the first dose of IMP on Day 1 and after 4 weeks treatment on the morning of Day 28

LAT8881

Cmax, Day 1

Cmax, Day 28

Placebo

Cmax, Day 1

Cmax, Day 28

Area Under the Concentration Time Curve From Zero to Infinity (AUC0-inf)

AUC0-inf after the first dose of IMP and after 4 weeks of treatment

LAT8881

AUC0-inf, Day 1

AUC0-inf, Day 28

Placebo

AUC0-inf, Day 1

AUC0-inf, Day 28

Time to Maximum Plasma Concentration of LAT8881 (Tmax)

Tmax after the first dose of investigational medicinal product (IMP) and after 4 weeks treatment with IMP

LAT8881

Tmax, Day 1

Tmax, Day 28

Placebo

Tmax, Day 1

Tmax, Day 28

Total

53
Participants

Age, Continuous

59.8
years (Mean)
Standard Deviation: 10.13

PainDETECT questionnaire (PD-Q) scores

20.9
units on a scale (Mean)
Standard Deviation: 4.38

Ethnicity (NIH/OMB)

Neuropathic pain history

Region of Enrollment

Sex: Female, Male

First Intervention (4 Weeks)

LAT8881, Then Placebo

Placebo, Then LAT8881

Washout/Baseline Period (3 Weeks)

LAT8881, Then Placebo

Placebo, Then LAT8881

Second Intervention (4 Weeks)

LAT8881, Then Placebo

Placebo, Then LAT8881

Drop/Withdrawal Reasons

LAT8881, Then Placebo

Placebo, Then LAT8881