Renu Gupta
Analyst · Canaccord
So the standardized laboratory methodology uses a semiquantitative assessment, primarily to assure consistency and reproducibility, and the quantitation can consistently be done up to 49 colonies. Thereafter, ranges of colonies are used. And this is in accordance with CDC recommendations published by Kent and Kubica back in 1985, and the Clinical and Laboratory Standards Institute, CLSI, as many of you might know, is an eminent body that standardizes laboratory methodology, and these are the tests and the methodology used in the published papers that I just referred to. So we've recommended the use of this semiquantitative methodology for our study as well. And just briefly, sputum specimens that are obtained from patients in accordance with these published recommendations are cultured in what we call liquid media or broth, as well as solid media or agar. The liquid media is held up to 6 weeks and the results are examined before being reported as culture negative. And the semiquantitative assessment of the NTM culture for sputum comprises of 7 steps. One being culture negative, and culture negativity is only documented when the liquid medium is negative. And 7 is the worst outcome or 4+. So essentially, the report would be as follows, Will: culture negative is confirmed with no growth in liquid medium; growth in liquid medium only as liquid positive; 1 to 49 colonies are manually counted on agar as individual colonies; and thereafter, there is a range of colonies that corresponds to 1+, which is 50 to 100 colonies; 2+, which is greater than 100 to 200 colonies; 3+, which is greater than 200 to 500 colonies; and 4+, which is greater than 500 colonies. These counts, as I mentioned, are actually performed upon visual inspection of the other plates utilizing the standardized methodology recommendation, that I just mentioned, from CDC and CLSI; and as mentioned previously, quite commonly used in the assessment of patients and clinical medicine to date. Many of you may not be very familiar with the change in CFU reduction of the semiquantitative scale for mycobacteriology, and more familiar with the change of CFU reduction in routine bacteriology, as was the case in our CF study for Pseudomonas aeruginosa, the 108 trial conducted earlier this year. That methodology is not appropriate in the NCM study, because the routine microbiology methodology is quite distinct from the mycobacterial culture. This is not easily and reliably and lucrative in being identified after a count of 50. Additionally, the sputum samples are prepared differently than routine microbiology. And I guess I'm getting a little bit too technical right now here. To summarize that, we are utilizing the best practice. And more importantly, the CDC and the CLSI recommendations for implementing the semiquantitative methodology for non-tuberculous mycobacteria which, incidentally, is similar for TB as well. This measure reveals a meaningful snapshot of whether the treatment is having a beneficial effect, as I alluded to earlier with the 2 publications, and determine effects [ph] as well. In summary, the awareness of the semiquantitative measure appears to be limited despite utilization by clinical centers. I believe it's largely because research efforts targeting the NTM lung disease population have been the first few data published, not really a whole lot since 1996 on this methodology. And all I can say at this point is that we are pleased to be leading this charge for evaluating a new antibiotic in the treatment of NTM lung disease, which might be an important addition to future treatment paradigms. And we're definitely aligning ourselves with some of the world's leading clinicians and laboratories to accomplish this.