Neil Di SpiritoSymin CharpentierAdam Schoen and Robert Ruh co-authored an article examining the FDA's guidance on clinical recommendations for "N of 1" gene therapies.

The article, published on March 15 in Clinical Leader and Cell & Gene, noted that as many as one in 25 patients may not be treated by their medication because of genetic factors that in some cases render existing therapies useless for that patient or prevent the use of those existing therapies due to adverse events.

"To eliminate ineffectiveness due to genetic differences, clinical trials of individual patients, described as an "N of 1," or single-subject trial, can provide crucial insight," they wrote. "The goal of a single subject trial is to determine the best treatment for an individual patient using objective, data-driven criteria. However, this is a difficult goal to achieve, and the regulatory path for conducting such single subject trials has been difficult to ascertain until the recent release of the FDA's clinical guidance on the matter."

According to the authors, the FDA's new draft guidance on individualized antisense oligonucleotide drugs, released in December 2021, "will have a broad impact on the gene therapy and clinical trials industry."

"Issuing the draft guidance for individualized antisense oligonucleotide drug products, the FDA begins sailing into new waters," they concluded. "The draft guidance will help clinicians and researchers chart a course when designing critical new therapies for severely ill patients with rare genetic conditions. Nevertheless, more work is needed to ensure that resources are used wisely to benefit these and all patients and that the right lessons are drawn from these initial forays into individualized treatments."

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