Wednesday, October 24, 2018

Investigating the landscape of US orphan product approvals

Kathleen L. Miller and Michael Lanthier, Orphanet Journal of Rare Diseases 2018 13:183, doi:10.1186/s13023-018-0930-3

The Orphan Drug Act was enacted in 1983 to encourage the development of drugs for rare diseases. Previous research has attempted to examine the impact of the Act by assessing either the number of orphan designations that have been granted or the number of new orphan drugs approved for marketing. This study provides a more in-depth understanding of the effect of the Orphan Drug Act by investigating all types of drug approvals with an orphan designation, along with multiple characteristics of the drugs, over the entire 35 years of the Act. These orphan approvals include: new molecular entities (new drugs approved first for a rare disease), secondary indications (an expansion from the first approved indication), and new formulations.

The deoxyribose phosphate lyase of DNA polymerase β suppresses a processive DNA synthesis to prevent trinucleotide repeat instability

Yanhao Lai, Yossi Weizmann, Yuan Liu. Nucleic Acids Research, Volume 46, Issue 17, 28 September 2018, Pages 8940–8952, Doi:10.1093/nar/gky700

The results indicate that pol β dRP lyase activity restrained the pol β-dRP interaction to suppress a pol β processive DNA synthesis, thereby preventing TNR deletion. This further implicates a potential of pol β dRP lyase inhibition as a novel treatment of TNR-expansion diseases.

Ion Mobility-Mass Spectrometry Reveals Details of Formation and Structure for GAA·TCC DNA and RNA Triplexes

Jiawei Li, Alexander Begbie, Belinda J. Boehm, Alexander Button, Charles Whidborne, Yannii Pouferis, David M. Huang, Tara L. Pukala. J. Am. Soc. Mass Spectrom. (2018). https://doi.org/10.1007/s13361-018-2077-9

DNA and RNA triplexes are thought to play key roles in a range of cellular processes such as gene regulation and epigenetic remodeling and have been implicated in human disease such as Friedreich’s ataxia. In this work, ion mobility-mass spectrometry (IM-MS) is used with supporting UV-visible spectroscopy to investigate DNA triplex assembly, considering stability and specificity, for GAA·TTC oligonucleotide sequences of relevance to Friedreich’s ataxia. We demonstrate that, contrary to other examples, parallel triplex structures are favored for these sequences and that stability is enhanced by increasing oligonucleotide length and decreasing pH. We also provide evidence for the self-association of these triplexes, consistent with a proposed model of higher order DNA structures formed in Friedreich’s ataxia. By comparing triplex assembly using DNA- and RNA-based triplex-forming oligonucleotides, we demonstrate more favorable formation of RNA triplexes, suggesting a role for their formation in vivo.

New Perspectives in Iron Chelation Therapy for the Treatment of Neurodegenerative Diseases

Nuñez, M.T.; Chana-Cuevas, P. Pharmaceuticals 2018, 11, 109. doi:10.3390/ph11040109


Iron chelation has been introduced as a new therapeutic concept for the treatment of neurodegenerative diseases with features of iron overload. At difference with iron chelators used in systemic diseases, effective chelators for the treatment of neurodegenerative diseases must cross the blood–brain barrier. Given the promissory but still inconclusive results obtained in clinical trials of iron chelation therapy, it is reasonable to postulate that new compounds with properties that extend beyond chelation should significantly improve these results. Desirable properties of a new generation of chelators include mitochondrial destination, the center of iron-reactive oxygen species interaction, and the ability to quench free radicals produced by the Fenton reaction. In addition, these chelators should have moderate iron binding affinity, sufficient to chelate excessive increments of the labile iron pool, estimated in the micromolar range, but not high enough to disrupt physiological iron homeostasis. Moreover, candidate chelators should have selectivity for the targeted neuronal type, to lessen unwanted secondary effects during long-term treatment. Here, on the basis of a number of clinical trials, we discuss critically the current situation of iron chelation therapy for the treatment of neurodegenerative diseases with an iron accumulation component. The list includes Parkinson’s disease, Friedreich’s ataxia, pantothenate kinase-associated neurodegeneration, Huntington disease and Alzheimer’s disease. We also review the upsurge of new multifunctional iron chelators that in the future may replace the conventional types as therapeutic agents for the treatment of neurodegenerative diseases.