Nasal symptoms (nasal congestion, rhinorrhoea, itching and sneezing) were scored on a scale from 0 to 3 where 0= absent symptoms, 3 = severe symptoms. TNSS was calculated as the sum of the response for all 4 individual nasal symptom scores. TNSS ranged from 0 to 12, where 0=absent symptoms, 3=severe symptoms. Higher the score, more severe the symptoms. Weighted mean (WM) of TNSS and its individual components (nasal congestion, rhinorrhoea, itching and sneezing) are presented on Day 8. Weighted mean was calculated over the time interval 0 to 4 hours after start of allergen chamber challenge by calculating the area under the curve of TNSS/component from time of the first observation to time of the last observation (AUC \[tf-t1 hours\]) using the trapezoidal rule, and then dividing by the actual relevant time interval (tf-t1) required by participant to complete the chamber challenge assessments. A Bayesian analysis was conducted to derive the posterior probability for TNSS.

AUC(0-4) is a measure of the average amount of study drug in the blood plasma over a period of 4 hours after the dose and AUC(0-t) is a measure average amount of study drug in the blood plasma over a period of last time of quantifiable concentration. Both the parameters were calculated by standard non-compartmental analysis. Blood samples for PK analysis were obtained at pre-dose, 0.5, 1, 1.5, 2, 3, 4, 6, 8 and 10 hours post-dose.

Cmax is defined as the maximum or "peak" concentration of a drug observed after its administration. Cmax is one of the parameters of particular use in estimating the bioavailability of drugs, by measuring the total amount of drug absorbed. It was calculated by standard non-compartmental analysis. Blood samples for PK analysis were obtained at pre-dose, 0.5, 1, 1.5, 2, 3, 4, 6, 8 and 10 hours post-dose.

Tmax is defined as the time of occurrence of Cmax. Blood samples for PK analysis were obtained at pre-dose, 0.5, 1, 1.5, 2, 3, 4, 6, 8 and 10 hours post-dose.

The concentration of capsaicin required to elicit 5 coughs was analyzed. The distributional properties were investigated, and the endpoint was logged (base 2) for analysis and the difference from Day -1 (baseline) was taken (equivalent to ratio on log scale).

The concentration of capsaicin required to elicit 5 coughs was analyzed. The distributional properties were investigated, and the endpoint was logged (base 2) for analysis and the difference from Day -1 (baseline) was taken (equivalent to ratio on log scale).

24 hour cough count (rate/h) following single dose of SB-705498 as compared to placebo were analyzed by first log transforming the cough counts taken on Day -1 and on Day 1 of each period in the 24 hours post dose. The cough count rates were log(10) transformed.

TSS was calculated based on a CDA challenge, done for 1 h in a controlled environmental exposure chamber which was validated for 14+/-5 degree Celsius (C), \<15% relative humidity and 5+/-3 feet per second (ft/sec) air velocity, 1 h and 24 h post dose on Day 14 (Day 15). TSS was calculated as the sum of the response for 3 components of nasal congestion, rhinorrhoea and post nasal drip. It was rated on a 4-point scale ranging from 0 to 3, where: 0=absent, 1=mild, 2=moderate, and 3=severe (symptom hard to tolerate). TSS score ranges from 0-9 with 0 representing an absence of symptoms and higher scores reflecting more severe symptoms. Weighted mean (WM) for TSS was calculated over the time interval 0 to 60 minute (m) after start of CDA challenge by calculating area under the curve (AUC) of the TSS via the linear trapezoidal method then dividing by the total duration that the participant took to complete CDA challenge assessments. WM is reported as least square (LS) mean.

The individual components of TSS was calculated based on a CDA challenge, done for 1 h in a controlled environmental exposure chamber which was validated for 14+/-5 degree C, \<15% relative humidity and 5+/-3 ft/sec air velocity, 1 h and 24 h post dose on Day 14 (Day 15). The individual component of TSS nasal symptoms were nasal congestion, rhinorrhoea (runny nose), and post nasal drip It was rated on a 4-point scale ranging from 0 to 3, where: 0=absent, 1=mild, 2=moderate, and 3=severe (symptom hard to tolerate). The scores of the individual components of TSS ranges from 0-3 with 0 representing an absence of symptoms and higher scores reflecting more severe symptoms. WM for TSS was calculated over the time interval 0 to 60 m after start of CDA challenge by calculating AUC of the TSS via the linear trapezoidal method then dividing by the total duration that the participant took to complete CDA challenge assessments. WM is reported as LS mean.