Clinical Notes
In addition to the genotypic and phenotypic information, a virco®TYPE HIV-1 report also provides complementary additional clinical information to further assist treatment decision making.
The additional clinical information is provided in text notes, called Additional Clinical Notes. The notes are conditional and are only provided if relevant for the sample virus. The conditions, as well as the content of the notes, have been reviewed and approved by virco's Technical Advisory Board and are updated when appropriate.
Additional Clinical Notes can be applied in various situations
1. The genotype may contain clinically relevant information that is not captured in the phenotype. The additional clinical notes will allow the physician to take that additional information into account when making clinical decisions
Example: Transitional Mutations.
A transitional mutation is any mutation that by itself does not cause phenotypic resistance, but is an indication of prior drug pressure and resistance, or evolving resistance. For instance, isolates that once had the resistance-associated mutations T215Y or T215F and are no longer exposed to NRTI often revert to T215 A, C, D, E, G, H, I, L, N, or V rather than wild type. These mutations by themselves do not affect phenotypic susceptibility. The presence of these transitional mutations is an indication of prior resistance to NRTI and suggests that a minor population of resistant viruses may still be present, but undetectable with the current genotyping technologies. Conversely, mutation T215S is also often detected in strains that go on to develop the resistance-associated mutations T215Y and T215F.
2. Some mutations affect resistance to only one drug, whereas others influence resistance to an entire class. Especially among the first generation NNRTI drugs, cross resistance is extensive and well documented. An additional clinical note gives a warning when the resistance analysis indicates 'susceptible' for one first generation NNRTI despite evidence of resistance to the other drugs in that class.
3. For some drugs the virco®TYPE HIV-1 Clinical Cut-Offs were developed from data obtained from sets of patients with specific characteristics. In such case a clinical note warns that these cut-off values may not be applicable to a broad patient population.
Example: tipranavir/r and etravirine CCO.
The data for the development of virco®TYPE HIV-1 Clinical Cut-Offs for tipranavir/r were obtained from the patients that participated in the RESIST studies. Hence, the CCO for tipranavir/r can be applied to other patients with the same characteristics (treatment history), but their relevance for patients different from those enrolled in RESIST has not been evaluated.
Clinical Notes Explaining the use of BCO - CCO2 Classification
