Introduction:
Allogeneic ex vivo therapies are in development where healthy donor cells ahve been modified to overcome allo-rejection with the purpose of creating so-called “off-the-shelf” cell therapies. Similarly, induced pluripotent stem cells (iPSCs) amy offer another option for the off-the-shelf manufacturing. These therapies may shorten and simplify manufacturing relative to autologous protocols, however, upstream ex vivo manufacturing challenges still exist in the form of donor or cell seleciton, gene editing, gene delivery efficiency, lot to lot variation and these challenges may be ocupled with concerns around cell persistence or risks such as graft-versus-host disease. Tareen, “Switching from ex viv to in vivo: approaches and considerations for generating cell therapies directly in the patient upon in vivo gene delivery” Cell &* Gene Therapy Insights, 2024; 10(5), 637-751).
With nearly three dozen FDA approved products, AAV vectors have been widely used for either ex vivo or in vivo gene delivery. The natural tropism of AAV serotypes or the malleability of the AAV capsid has made them excellent vehicles for in vivo gene delivery and CAR-T generation. Gendicine delivers an Adenovirus vector direclty to the tumor. Antoher intratumorally delivered viral therapy is IMlygic which was approved in 2015 for melanoma. Imylgic is an oncolytic virus deviered form herpes simplex virus 1 that encodes GM-CSF. Zolgensma, FDA approved in 2019 for spinal muscular atrophy, takes advantage of the natural tropism of AAV9 towards neurons and its ability to cross the BBB to deliver DNA coding for teh SMN protein upon IV adminsitration. (Tareen, “Switching from ex viv to in vivo: approaches and considerations for generating cell therapies directly in the patient upon in vivo gene delivery” Cell &* Gene Therapy Insights, 2024; 10(5), 637-751).
Importance and Difficulty of Drug Delivery and Formulation
The success of most peptide and protein drugs is dependent upon the delivery of the biologically active form to the site of action. In the design and development of formulations to achieve this goal, the formulation scientist must consider the clinical indication, pharmacokinetics, toxicity and physicochemical stability of the drug. The development of a stable formulation is a necessary step for each new protein or peptide therapeutic. The degradation pathways and their impact on stability should be systematically analyzed and competing degradation rates must be balanced to arrive at the most stable formulation possible. The design and production of protein and peptide drug formulations is not well developed and many of the mechanisms for stabilization and delivery of these drugs have not been determined. The route and fequency of administration and the bioactivity or portency of the drug in humans are critical issues that are often not addressed in the pre-IND animal studies. (Cleland and Langer, “Formulation and Devliery of Proteins and Peptides,” American Chemical Society, 6 pages (1994).
In vivo Delivery Platforms:
There are several approved in vivo genetic therapies that are based on viral vectors (e.g., adenovirus, AAV, retriviral vector), oncolytic viruses (e.g., HSV-1), lipid nanoparticles (e.g., COVID-19 mRNA vaccine–a mRNA encoding a pre-fusion conformation of teh SARS-CoV-2 spike protein is delivered intramuscularly using lipid partciles) and nucelic acids (antisense oligos, RNAi, DNA plasmid, morpholinos). Each of these approved delivery platforms ahve diverse mechanisms of action due to their unique biology. (Tareen, “Switching from ex viv to in vivo: approaches and considerations for generating cell therapies directly in the patient upon in vivo gene delivery” Cell &* Gene Therapy Insights, 2024; 10(5), 637-751).
Delivery to Particular Anatomical Sites
Rectal administration: are typically by suppositories which can be prepared by mixing an active ingredient with non-irritating excipients or carriers such as coca butter, polyethleneglycol or a suppository wax, which are solid at ordinary temperatures but liquid at body temperature and thus melt in the rectum or vaginal cavity and release the active component.
Topical administration: oftein include ointments, powders, sprays and solutions. The active component is admixed under steril conditions with a physiologically acceptable carrier.
Self-Administered Drug Delivery systems
Disposable pen: A medical delivery pen is described in US5,308,341. A doser device is described in US 6,302,855.
Specific Types of Carriers for Drugs
SIgA: In the intestine, SIgA has been shown to specifically bind to a specialized type of enterocytes called M cells. These cells are able to sample antigens in the intestinal lumen and to present them in an intact form to the underlying immune structure named Peyr’s pathches. Binding of SIgA to M c3ells raises the possibility to use these molecules as antigen carrier to target mucosal immune sites exemplified by PP. This has been validated by oral administration of heterologous SIgA to induce producing of IgG, IgM and IgA positive Cells specific for the SC and IgA moieties in the PP in the absence of adjuvant, oral administration of antigenized SIgA carrying a 9 amino acid epitope form Shigella flexneri within SC induced an immune response against the epitope in the presence of an adjuvant (Favre, J Chromatography B, 786 (2003), pp. 143-151.
Fragment antibody (Fab):
–Facioscapulohumeral muscular dystrophy (FSHD):
FSHD is a rare disease characterized by progressive loss of skeletal muscle, which causes profound weakness. It is estimated to affect approximately 16,000 to 38,000 people in the U.S. and 35,000 people in Europe. There is wide variability in age of onset with FSHD. Symptoms typically begin to appear in the teen years. In some cases, individuals do not begin to experience the muscle weakness characteristic of FSHD until well into adulthood. A very rare form of FSHD, often called infantile FSHD or IFSHD, is particularly debilitating, with symptoms beginning in infancy or early childhood. The symptoms of FSHD often emerge first with a loss of facial muscle strength, making it difficult to smile or use a straw. Weakness typically progresses to all major muscle groups including the arms, torso, legs, and abdomen and can lead to limited mobility. The severity of symptoms varies widely. People living with FSHD can also experience joint and spinal abnormalities, including protrusion of the shoulder blades. FSHD is caused by aberrant expression of a gene called DUX4. In a healthy individual, DUX4 is active for only a short time in early embryonic development. In individuals with FSHD, the DUX4 gene remains “on” long after it is supposed to be silenced. This activation leads to surplus production of the DUX4 protein, which causes the gradual destruction of muscle cells throughout the body. See Dyne
—-DYNE-302 is Dyne’s product candidate being developed for people living with FSHD. DYNE-302 consists of a fragment antibody (Fab) that binds to the transferrin receptor 1 (TfR1) which is highly expressed on muscle, conjugated to an siRNA designed to reduce DUX4 expression. Dyne has generated comprehensive preclinical data supporting its FSHD program demonstrating robust and durable DUX4 suppression and functional benefit in both in vitro and an innovative in vivo model developed by Dyne.
DNA nanotechnology:
DNA nanotechnology, a technique applying the biomolecular self-assembly property of DNA, has a wide range of applications in various disciplines, especially in drug delivery. Upon the formation of specific base pairs, DNA strands hybridize with each other and can then be easily engineered into a functional nanostructure with highly spatial programmability, such as designed DNA nanodevies compatible with the immne syste and DNA based smart drug delviery vehicles. As a promising diagnostic and therapeutic nanoplatform, DNA strands combined with other nanoscale materials, such as nanowires, nanotubes, nanosheets, polymers, gold nanoparticles (AUNPs), quantum dots, and iron oxides, show a great potential in early diagnosis of cancer and themely therapy. DNA tetrahedron, a 3D self-assembled DNA origami nanostructure, is widely used as a sensitive biosensing probe which cn be rapidly interalized by a caveolin dependent pathway. (Chen, “DNA nanotechnology for cancer diagnosis and therapy” International J. of Molecualr Scienes, 2018).
Gold Nanomaterials:
God nanomaterials such as gold nanopartciles (AuNPs) and gold nanorods (AuNRs) have shown great potential for targeting and drug delviery. Their wide applicaitons can be attributed to their advantages, such as ease of synthesis, controllable shape, and tunable surface functionalities. Their well-known optical properties endow them with ideal performance for medical imaging and even for photothermal therapy in the field of caner diagnosis and therapy. Chen, “DNA nanotechnology for cancer diagnosis and therapy” International J. of Molecualr Scienes, 2018)