hpv genotyping trial design, page-8

Thank you for the informed post ProfFrazer.

ProfFrazer: "Please correct me if I'm wrong here buy my understanding is that the current clinical validation study has been designed to provide clinical data on PapType's effectiveness in ASCUS Triage patients NOT as a screening test. PapType can be clinically validated under the design of the current GBI study but not as a screening test."

Agreed, this trial design would not be informative as to the applicability of PapTypes as a screening test.

ProfFrazer: "Conversely to what a2g stipulates regarding the skew toward an ASCUS Triage study naturally generating a higher true positive rate than that of a screening population the key for any test in gaining an approval for a screening indication is having a low false negative rate or very high negative predicative value."

Yes, and large numbers of patients WILL need to be in a study design to determine that PapType has a low false positive rate regardless if PapType is to be used in a triage testing or screening program. This study design is poor in providing data on the false negative rate of PapType due to the over-representation HC2+ and histology + samples.

ProfFrazer: "The design of the current study is relevant to generating clinical data from clinical samples that have been tested against both HC2 and histology. Such a study will provide a good guide as to PapType's clinical effectiveness versus HC2 in ASCUS Triage"

Agreed. This study will prove useful in determining how effective PapType will be in analysing ASCUS patients. ASCUS patients represent approximately 5% (although this figure varies from lab-to-lab and between populations) of all women undertaking HPV screening.

This is indeed an informative and important trial for GBI that will provide some useful information about PapTypes performance. However, IMO I would not consider it a 'pivotal' trial. 'Poor' results certainly won't be the death knock for PapType due to the small scale and limited scope of the trial. This fact in line with the appearance that GBI appear to still tweaking some technical aspects of the test provide an opportunity for valuable information to be gained from any 'poor' trial results that can drive further product modifications or enhancements (if necessary). 'Good' results would certainly be a positive in the eyes of any potential future partner who may well be inclined to explore further testing with GBI. Time will tell.