1 September 2017 - - New York, New York-based biopharmaceutical and healthcare products specialist Pfizer Inc. (NYSE: PFE) has published a new interim analysis of long-term data from four studies indicating that treatment with tafamidis is associated with delay in disease progression in patients with hereditary transthyretin amyloid polyneuropathy (TTR-FAP) and was well tolerated, with no unexpected side effects, the company said.
The publication, "Long-term safety and efficacy of tafamidis for the treatment of hereditary transthyretin amyloid polyneuropathy: results up to 6 years," is available online in the journal Amyloid: The Journal of Protein Folding Disorders. 
The analysis included patients with the most common TTR-FAP mutation, Val30Met, who either initiated treatment with tafamidis at the beginning of the pivotal study or who started treatment 18 months later during an open-label extension, as well as non-Val30Met patients who completed 12 months of treatment and then continued in the same open-label extension.
The findings reported in Amyloid are from an analysis of an ongoing, long-term, open-label extension study of tafamidis in 93 patients with TTR-FAP who had participated in previous studies with the medication. Of these 93 patients, 75 had the Val30Met mutation and 18 had the non-Val30Met mutation. Different TTR mutations can be associated with differences in disease symptoms and severity.
The analysis suggests that, by month 66, patients who started tafamidis at the start of the 18-month pivotal trial had numerically less disease progression than patients who started on placebo, based on the degree of worsening in three standard measures, and was also less likely to to progress to the next ambulatory stage, for example, from no assistance required to needing a cane to using a wheelchair .
The analysis also suggested the rates of worsening in NIS-LL, NIS-LL muscle weakness, and TQOL over time were less for the patients who started on tafamidis versus placebo on entry to the pivotal trial; moreover, after the placebo, in patients switched to tafamidis during the open-label extension, the rates slowed and were comparable to those seen in patients who had been started on the medication from the beginning of the study.
In the patients with non-Val30Met mutations, who had previously completed a separate, 12-month, open-label study, some worsening of NIS-LL and other measures were observed.
The lack of a control or comparator group of non-Val30Met patients made interpretation of the findings in those patients difficult and is a limitation of this new analysis.
Among all 93 patients in the analysis, tafamidis was generally well-tolerated, with no unexpected safety issues identified.
As a leader in TTR amyloidosis, Pfizer Rare Disease continues to partner with the FDA regarding a potential path to approval of tafamidis for TTR-FAP, as the company hopes to achieve the objective of providing TTR-FAP patients living in the United States with the same treatment option as those patients living in many other parts of the world.
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