Australia’s health regulator has stood by its recent testing of medical cannabis products and denied its initial analysis was wrong.
The Therapeutic Goods Administration (TGA) was forced to defend its processes after third-party testing of five products returned different results to that of the regulator.
It said a number of factors may have contributed to the varying results, and ruled out any move to standardise individual testing labs.
The third-party tests appeared to exonerate three of five products that had earlier failed a TGA potency audit.
A report published by the TGA had named two Althea products, and one each from Little Green Pharma, Spectrum Therapeutics and Bedrocan as those which “failed” its analysis.
Follow-up tests subsequently found the Althea and Spectrum products were within required limits with the other two only fractionally out.
The TGA said in a statement: “While the results from the third-party testing show different results, this does not imply that the TGA’s results are not accurate.
“A number of factors can lead to differences in results including variability within the batch [which is] particularly problematic for plant samples, the precision of the method used [which can] be affected by non-representative sample size and extraction, and accuracy of the method [which] can be affected by poor/incomplete extraction and the accuracy of the reference material used.
“These factors can contribute to unacceptably high measurement uncertainty relative to the acceptance limits.
“In addition, the accuracy of some commercial reference standards supplied as dilute solutions in methanol is questionable as they were observed to give significantly different results to other standards.
“This inconsistency could lead to significant differences in results.”
The different in results led to several calls to adopt standardised lab testing.
But the TGA ruled out such a move, saying it is “not working towards standardising individual licensed testing laboratories”.
“They are assessed independently by TGA GMP inspectors to ensure that they are meeting the requirements set out in the manufacturing standard, PIC/S Guide,” a spokesperson said.
“The PIC/S Guide does not have specific requirements around standardisation of individual manufacturers.”
The TGA added that “not all laboratories conduct the same testing and not all laboratories have the same testing equipment/capabilities”.
“It is up to the individual licence holder to ensure the accuracy of their test results through the use of equipment qualification, equipment calibration, method validation, certified reference standards, control of computerised systems (as applicable), staff training and peer/management review of raw data and related calculations prior to release of test results.
“These activities are reviewed in detail during GMP inspections conducted by the TGA at a frequency determined by a risk-based framework.
“The requirements are the same whether the laboratory forms part of a manufacturing facility conducting testing exclusively for its own purposes or is a third-party testing laboratory offering testing services to a number of unrelated clients.”