June 9, 2022
Thank you for the opportunity to speak today on behalf of the National Center for Health Research. I am Dr. Nina Zeldes, a senior fellow at the Center. We analyze scientific data to provide objective health information to patients, health professionals, and policy makers. We do not accept funding from drug or medical device companies, so I have no conflicts of interest.
We agree with FDA scientists in their summary that “The uncertainty regarding efficacy at 24 months following treatment is particularly problematic in the context of the recent discovery of a serious safety concern, the development of MDS, a life-threatening malignancy which occurred in 3 subjects.” We share the concerns of the FDA that two of the events are definitely related to the product and the third is highly likely to be related. You will recall that the FDA points out that “the rarity of the condition in the absence of a provoking event, and the lack of known association between MDS and CALD are other factors that have influenced our concern regarding a causal relationship.” Also, as FDA highlighted in the materials, the “growth of clones with proto-oncogene integration sites” may point to these clones having a selective advantage and may evolve into cancer.” We also share FDA’s concern about the cases of Acute Myeloid Leukemia (AML) that were observed following treatment with a related LVV-based product in patients with sickle cell disease.
We also agree with FDA that because most of the subjects had less than two years of follow-up data, longer follow-up will uncover additional cases of MDS as a potentially life-threatening complication of treatment.
Please take these concerns into consideration as you conclude whether the data convince you that the likely benefits outweigh the likely risks.