A retrovirus is any virus belonging to the viral family Retroviridae. All The genetic material in retroviruses is in the form of RNA molecules, while the genetic material of their hosts is in the form of DNA. When a retrovirus infects a host cell, it will introduce its RNA together with some enzymes into the cell. This RNA molecule from the retrovirus must produce a DNA copy from its RNA molecule before it can be considered part of the genetic material of the host cell. Retrovirus genomes commonly contain these three open reading frames that encode for proteins that can be found in the mature virus. Group-specific antigen (gag) codes for core and structural proteins of the virus, polymerase (pol) codes for reverse transcriptase, protease and integrase, and envelope (env) codes for the retroviral coat proteins (see figure 1).Figure 1. Genome organisation of retroviruses. The process of producing a DNA copy from an RNA molecule is termed reverse transcription. It is carried out by one of the enzymes carried in the virus, called reverse transcriptase. After this DNA copy is produced and is free in the nucleus of the host cell, it must be incorporated into the genome of the … Continue reading →

Gene therapy utilizes the delivery of DNA into cells, which can be accomplished by several methods, summarized below. The two major classes of methods are those that use recombinant viruses (sometimes called biological nanoparticles or viral vectors) and those that use naked DNA or DNA complexes (non-viral methods). All viruses bind to their hosts and introduce their genetic material into the host cell as part of their replication cycle. This genetic material contains basic 'instructions' of how to produce more copies of these viruses, hacking the body's normal production machinery to serve the needs of the virus. The host cell will carry out these instructions and produce additional copies of the virus, leading to more and more cells becoming infected. Some types of viruses insert their genome into the host's cytoplasm, but do not actually enter the cell. Others penetrate the cell membrane disguised as protein molecules and enter the cell. There are two main types of virus infection: lytic and lysogenic. Shortly after inserting its DNA, viruses of the lytic cycle quickly produce more viruses, burst from the cell and infect more cells. Lysogenic viruses integrate their DNA into the DNA of the host cell and may live in … Continue reading →

Dive Brief: Even as gene therapies are being touted as the next wave of innovation that could offer cures for certain genetic conditions, it remains to be seen whether these products are actually commercially viable. There has yet to be a gene therapy approved in the U.S. (although Spark Therapeutics' application is pending), but two of the transformative drugs have been on the market in Europe. Yet neither of those commercially available gene therapies have found much success. GlaxoSmithKline plc. said just last week it is looking to move away from its rare disease portfolio, including the gene therapy Strimvelis. Meanwhile, uniQureannounced back in April it would not renew the marketing authorization application in Europe for its already-approved gene therapy Glybera. This latest move by Chiesifurther exemplifies the challenges gene therapy producers face. The announcement ends a deal which has been in place since 2013. Chiesisaid in a statement that the decision was "driven by recent changes in our strategic priorities." uniQuretried to put brave face on the news, but partnership exits are rarely good news for a biotech. "By regaining unencumbered, global rights to a late-stage program that has demonstrated significant clinical benefit for patients with hemophilia B, we … Continue reading →

Philadelphia gene therapy company Spark Therapeutics has applied to the European Medicines Agency for approval to sell its treatment of rare inherited blindness in the European Union. The experimental therapy, Luxturna, or voretigene neparvovec, is under priority review with the U.S. Food and Drug Administration, with a possible approval date of Jan. 12, 2018. Spark was spun out of Childrens Hospital of Philadelphia, based on research led by Katherine A. High, Sparks cofounder, president, and chief scientific officer. If approved, it would be the first gene therapy for a genetic disease in the United States. With Luxturna now in regulatory review on both sides of the Atlantic, we are building out our medical and commercial infrastructure to bring the drug to patients, said John Furey, Sparks chief operating officer. For the first time, adults and children, who otherwise would progress to complete blindness, have hope for a potential treatment option that may restore their vision, he said. About 3,500 people in the United States and Europe live with the disease. The review period will begin in Europe once the agency validates the application, Spark said. Published: August 1, 2017 3:01 AM EDT | Updated: August 1, 2017 11:40 AM EDT … Continue reading →

Chiesi has cut its ties to uniQures hemophilia B gene therapy. The split gives uniQure full rights to AMT-060 but leaves it without a partner to cofund R&D as it closes in on the start of a pivotal trial. Italian drugmaker Chiesi picked up the rights to commercialize AMT-060 in certain markets in 2013 as part of a deal that also gave it a piece of Glybera, the gene therapy that made history by coming to market in Europe only to flop commercially. Chiesi backed out of the Glybera agreement earlier this year and has now completed its split from uniQure by terminating the hemophilia B pact. Amsterdam, the Netherlands-based uniQure framed the termination as it reacquiring the rights to AMT-060, rather than Chiesi dumping the program. But as the deal will see money transfer from Chiesi to uniQure and the former stated a shift in priorities prompted it to sever ties to AMT-060, it seems clear the Italian drugmaker wanted to exit the agreement. That leaves uniQure facing the prospect of taking AMT-060 into a pivotal trial without the financial support of a partner. Chiesi and uniQure have evenly shared R&D costs since 2013. The loss of the support … Continue reading →