Proposed Implementation

Introduction

Applying new technological innovations in the real world implies a whole set of challenges that must be considered. Here, we present a proposition that discusses the potential applications, the intended end-users, safety considerations, planned preclinical and clinical trials, and other challenges regarding the implementation of Vesiprod in the real-world healthcare facilities. Economic matters and the scientific interest around exosomes are also important factors to analyze, but it will be done in the Entrepreneurship section of our wiki.

Potential applications and end-users

Our development of a cell-based system to produce designer exosomes, efficiently loading a designer cargo into an exosome with a specific targeting membrane protein, can have uncountable medical applications especially in the field of therapeutics.

Exosomes, similarly to the widely known synthetic liposomes, are lipid-bound nanoparticles, an aspect which improves the fundamental characteristics of free drugs, such as their stability and solubility, and their pharmacokinetics, by protecting the drugs against degradation and providing a sustained and prolonged release of the incorporated drug. Moreover, as opposed to liposomes, EVs have multiple advantages due to their cellular origin: higher biocompatibility and bioavailability, lower immunogenicity and cytotoxicity, surface proteins that provide specific tissue targeting, superior drug delivery capacity and the ability to cross biological barriers, such as the blood-brain or the blood-testicle barriers. For all these reasons, exosomes are already starting to be used as a therapeutic drug-carrying platform in recent years, with promising results.

Since our project provides a solution for the main problems that were impeding the extensive implementation of exosomes, which were the lack of a system to create designer EVs and the lack of simple and efficient collection and purification techniques, combined with the inherent advantages of exosomes, we believe that our project gives the opportunity to create a vastly wide range of therapeutic products for many diseases, even some that we still consider intractable, like cardiovascular, infectious, neoplastic, autoimmune, and even neurodegenerative diseases.

The main therapeutic strategies that we envision for our designer exosomes are based on nucleic acid-based drugs, for example, the delivery of siRNA or miRNA in order to inhibit specific gene expression and protein synthesis, or the delivery of substituting mRNA for specific genes to increase their function, both strategies useful in many different disease contexts. Other options include the direct delivery of substituting peptides or proteins, or the delivery of classical drugs, but with the benefits of a more bioavailable and specific distribution.

Firstly, the possibilities for siRNA/miRNA delivery are vast. Relevantly, they include the treatment of neoplastic diseases, specially by impairing gene expression of oncogenes (e.g., transcription factors –Myc–, intracellular signaling proteins –Ras, Rab, PI3K–, apoptosis inhibitors –Bcl-2–, growing factor receptors –Her-2–, cellular cycle mediators –cyclins and CDKs–, angiogenesis mediators –VEGF–, hormone receptors, etc.) with potential efficacy in virtually any type of cancer. Due to their very well understood and constant molecular changes in hematologic neoplasms (leukaemias, lymphomas, myelomas, etc.), we believe that they are the ideal target for this potential application. Another relevant field of potential application are neurodegenerative diseases, by inhibiting gene expression of the protein that specifically aggregates in each disease (e.g., beta-amyloid in Alzheimer’s disease, tau in Alzheimer’s disease, corticobasal degeneration, Steele-Richardson-Olszewski syndrome, or frontotemporal dementia, alpha-synuclein in Parkinson’s disease, Shy-Drager syndrome, or Lewy body dementia, prionic protein in Creutzfeldt-Jakob disease, etc.), or with a more general approach by using miRNA that promote neurogenesis (e.g., miR-21a) or inhibit neuroinflammation (e.g., miR-146a). The third group of diseases with the most therapeutic possibilities are autosomal dominant mendelian genetic diseases with increased or aberrant protein production, inhibiting the expression of the mutant allele (e.g., huntingtin in Huntington’s disease; parkin, dardarin or synuclein in genetic Parkinson’s disease; presenilin 1-2 or amyloid precursor protein in genetic Alzheimer’s disease, SCA1-48 in autosomal dominant spinocerebellar ataxias, myotonin in Steinert’s muscular dystrophy, oncogene RET in hereditary familial cancer syndromes like multiple endocrine neoplasia 2A and 2B or familial medullary thyroid cancer, GCK in hyperinsulinism, FGFR3 in achondroplasia, FV in primary thrombophilias like V factor of Leiden, etc.). For cardiovascular diseases, there have been studies for multiple miRNA to modulate processes like angiogenesis and fibrosis, which open the door to treat ischemic diseases (e.g., myocardial infarction, ischemic stroke, peripheral arteriopathy), by inhibiting fibrosis (e.g., miR-29b) or promoting angiogenesis or cardiac function (e.g., miR-210, miR-132, miR-21, miR-451, miR-146a); moreover, fibrosis could be also promoted (e.g., miR-208a) to treat other cardiovascular diseases like dilated cardiomyopathy. Finally, other options could be infectious diseases (e.g., prophylaxis or treatment of HIV infection by inhibiting its coreceptors like CXCR4 and CCR5), endocrine-metabolic diseases (e.g., increasing glucose tolerance with miR-99b), musculoskeletal diseases (e.g., increasing bone regeneration with miR-375) or the treatment of acute and chronic inflammatory diseases by the inhibition of the expression of pro-inflammatory cytokines (e.g., IL-1, IL-6 or TNF-alpha for autoimmune and autoinflammatory diseases, graft versus host disease, etc.).

Secondly, there are also multiple possibilities for mRNA delivery. The main group of diseases in which this option could be more useful are mendelian genetic disorders with reduced or dysfunctional protein production, substituting the expression of the mutant allele. This would be applicable to autosomal dominant diseases due to loss of function or haploinsufficiency (e.g., SUR or KIR in neonatal diabetes mellitus, GH in growth deficit, GCK or HNF in maturity-onset diabetes of the young, RET in Hirschsprung’s disease, and specially tumor suppressor genes in hereditary familial cancer syndromes like BCRA1-2 in familial breast-ovarian cancer, APC and DNA repairing genes in familial colon cancer, RB in retinoblastoma, TP53 in Li-Fraumeni syndrome, NF1-2 in neurofibromatosis, MEN1 in multiple endocrine neoplasia 1, VHL in Von Hippel Lindau syndrome, SDH in familial paraganglioma, PTEN in Cowden’s syndrome, STK11 in Peutz-Jeghers’ syndrome, PRKAR1A in Carney’s complex, etc.) and specially to autosomal or X-linked recessive diseases by loss of function (e.g., LCT in lactose intolerance, GCK in neonatal diabetes mellitus, CFTR in cystic fibrosis, HFE in hereditary hemochromatosis, ATP7B in Wilson’s disease, CYP21A2 in congenital suprarenal hyperplasia, dystrophin in Duchenne’s or Becker’s muscular dystrophies, Apo-B, LDL-R or PCSK-9 in familial hypercholesterolemia, frataxin in Friedrich’s ataxia, as well as many different enzymes to treat the more than 600 diseases that constitute the group of metabolism congenital errors, like phenylketonuria, alkaptonuria, homocystinuria, oculocutaneous albinism, tyrosinemia, galactosemia, mucopolysaccharidoses, sphingolipidoses –Tay-Sachs, Gaucher and Niemann-Pick diseases–, Lesch-Nyhan syndrome or adrenoleukodystrophy). Apart from this main group of diseases, there are also other options, like the treatment of acute and chronic inflammatory diseases by the delivery of mRNA of anti-inflammatory cytokines (e.g., IL-10, IL-35 or TGF-beta for autoimmune and autoinflammatory diseases, graft versus host disease, etc.), neurodegenerative diseases (e.g., mRNA of dopa-decarboxylase or catalase for Parkinson’s disease), neoplastic diseases (e.g., mRNA for a suicide gene directly injected in a tumour), etc. Additionally, this technique goes beyond therapeutic applications and could also be used as a prophylactic treatment, allowing the development of “vaccines” (immunotherapy) against infectious diseases (e.g., mRNA of pathogen-derived proteins) and even against cancer (e.g. mRNAs for tumor-derived proteins); and it also could be used in laboratory and clinic environments to perform genetic therapy (e.g., mRNA of Cas9 to use CRISPR technology to induce or correct DNA errors).

Finally, we propose some other delivery applications for our exosomes, using peptides or classical drugs. Peptides could be used similarly to mRNA as cancer or infection “vaccines” by the delivery of tumor or pathogen-derived antigenic peptides to induce an antigen-specific T lymphocyte response against the tumoral cells or against the pathogen. As previously introduced, the delivery of classical drugs using exosomes could have advantages like the reduction of their side effects, targeted delivery and improving their pharmacokinetic profile (e.g., crossing biological barriers, increasing stability, etc.), specially for chemotherapeutic drugs (e.g., anthracyclines, cyclophosphamide) or antibiotic drugs (e.g., amphotericin).

In conclusion, the real-world use we envision for our project is specially oriented to its use as a therapeutic weapon against the cited vast group of diseases, in some cases even definitively curing them. Therefore, our proposed end users would be the pharmaceutical industry, in concretion, the members of research groups centered on therapeutics development. Eventually, upon governmental approval and obtention of all required certifications, the therapeutic products obtained through the use of our kit can be purchased by the public health system and private institutions, making medical providers and patients all over the world the indirect and final end-users of Vesiprod, having the potential to change medicine as we know it today by giving symptomatic and even prognostic-changing possibilities to many diseases we still consider intractable.

Preclinical trials

Regarding the clinical implementation of Vesiprod, the product must be validated, as with all medical innovations, through medical trials. Data collection through preclinical and clinical trials to evaluate and assess the prototype and its products is essential to obtain the right certifications to realize Vesiprod in the real world.

On that matter, we already count to do some first steps, like performing in vitro and in vivo studies to demonstrate that this potential is actually applicable as a real-world therapeutic weapon. We have decided to make an exemplificative model as a part of our project as a functional validation. This proof of concept has a therapeutic purpose and is applied to both an in vitro and an in vivo model of Burkitt’s lymphoma, using one of the proposed applications that has been explained previously. We have explained how siRNA/miRNA delivery could be used in malignant neoplastic diseases, by impairing gene expression of oncogenes, possibly being one of the most attractive potential applications of our project in the real world. We have also stated that hematologic neoplasms, such as Burkitt’s lymphoma, could be the ideal target for this potential application due to their constant molecular changes in relation with specific oncogene activation. Combining all of this, we are aimed to demonstrate the validity and applicability of our project by “taking the job” of its future direct users, by using our kit to create designer exosomes, its cargo being siRNA to suppress the expression of the oncogene MYC, a transcription factor constantly implied in the pathogenesis of Burkitt’s lymphoma, and its targeting membrane protein being CD19-L, a surface adhesion molecule which directly interacts with CD19, also a surface molecule that is highly expressed in Burkitt lymphoma’s cells and is also highly specific to leukocytes, reducing the delivery of the cargo to other body tissues. Finally, we will deliver these exosomes firstly to an in vitro culture of Burkitt’s lymphoma’s cells and afterwards also to an in vivo model of Burkitt’s lymphoma in the extraembryonic membranes of a chicken. Afterall, we will have proved the functionality of our system and demonstrated that the explained application possibilities are achievable.

In addition to this demonstration of functionality, in a cooperative effort with another IGEM group, [igem_iisertvm], we have also researched about the possibility to perform some preclinical studies in animals, each team using their correspondent nanovesicles (exosomes in our case and outer membrane vesicles in theirs) to treat their correspondent disease. Apart from these two aspects, the design we have created and now describe is equivalent for both of the teams. We would do an animal study using a mouse model with Burkitt lymphoma to demonstrate the efficacy, safety, and possible adverse effects of the exosomes from our kit. To be more rigorous, in a first phase, exosomes would be used without any cargo, to establish their safety as a delivery carrier, while in a second phase, the engineered exosomes loaded with siRNA against MYC and overexpressing CD-19-L would be used to demonstrate both their safety and efficacy. In both phases, single dose toxicity testing and repeated dose toxicity testing will be performed, in a group of mice intravenously and in another group subcutaneously, to compare the route of administration in terms of efficacy, safety, and local toxicity. Single dose toxicity testing would consist in the administration of ten times the intended dosage for humans, being the models observed for 14 days, to establish the Minimum Lethal Dose (MLD) and Maximum Tolerated Dose (MTD) and to recollect the symptoms, mode of death, effects on body weight, and gross pathological changes. In repeated dose toxicity testing, exosomes would be administered daily for a week after distributing mice in four groups with different levels of doses (control, low level –causes no observable toxicity–, intermediate level –causes symptoms–, and high level –causes observable toxicity–), and after that, the mice from the four groups would undergo behavioral, physiological, biochemical, and microscopic analysis. Upon completion of the 7-days repeated dose toxicity testing, repeated dose toxicity studies will be conducted for longer periods: 14, 28, 90 and 180 days. In all the cited studies, apart from the assessment of toxicity, the concentration of both exosomes and siRNA against MYC will be monitored in plasma (by blood extraction) and in key organs like the liver, spleen, lung, and kidney (by direct biopsies).

Clinical trials

The final step to implement our exosomes in the real world would be to perform a clinical trial to assess its tolerability and its effectiveness against the target diseases we have listed, depending on the cargo that the exosomes contain. For exemplificative purposes, we proceed to the description of a proposed clinical trial for our engineered vesicles against Burkitt’s lymphoma.

PHASE 1.

• Name: A phase I, open-label, multicenter, dose escalation study of engineered exosomes with MYC siRNA and overexpression of CD22 in treating participants with Burkitt’s lymphoma.
• Study type: Interventional (clinical trial).
• Estimated enrollment: 30 participants.
• Allocation: N/A
• Intervention model: Single group assignment.
• Masking: None (open label).
• Primary purpose: Treatment.
• Summary: This phase I trial has the goal to study the safety and tolerability (finding the best dose and finding the side effects) of engineered exosomes loaded with MYC small interference RNA, to suppress the overexpression of MYC oncogene in Burkitt’s lymphoma, and with overexpressed of CD22, to improve the specific delivery of the cargo to lymphoid tissue, therefore having a potential for meaningful single agent antitumor activity in treating participants with Burkitt’s lymphoma refractory to other lines of treatment.
• Objectives:
  1. To identify the maximum tolerated dose (MTD) of the engineered exosomes.
  2. To identify the dose-limiting toxicities (DLT) of the engineered exosomes.
  3. Evaluate the pharmacokinetic profile of the engineered exosomes.
  4. Assess the overall response rate with this therapy.
  5. Assess the disease control rate (partial response + stable disease) with this therapy.
  6. Determine median progression-free survival (PFS) with this therapy.
  7. Determine median overall survival (OS) with this treatment.
  8. Evaluate optional tissue collection and serum-derived exosomes and circulating-free DNA and RNA showing MYC sequence or siRNA against MYC sequence.
• Outline: This is a dose-escalation study in which participants receive the engineered exosomes intravenously over 15-20 minutes on days 1, 4 and 10. Treatment repeats every 14 days for up to 3 courses in the absence of disease progression or unacceptable toxicity. Participants who respond may continue 3 additional courses. After completion of treatment, participants are followed up at 30 days, then every 3 months for up to 1 year.
• Outcome measures:
  1. MTD determined by DLT, with treatment-emergent adverse events graded according to the NCI CTCAE, version 5.0.
  2. Minimal residual disease rate in high-risk patients, modeled using logistic regression.
  3. OS, estimated using the Kaplan-Meier product limit estimator.
  4. PFS, estimated using the Kaplan-Meier product limit estimator.
• Eligibility criteria:
  • Age: 18 years and older (adult).
  • Sexes: All
  • Healthy Volunteers: No
  • Inclusion criteria:
    1. Patients with histologically confirmed Burkitt’s lymphoma with a demonstrated MYC translocation, either t(8;14), t(2;8) or t(8;22).
    2. Patients must have documented progression or stable disease on one or more lines of systemic therapy. If disease is stable, the patient must have completed at least 4 months of chemotherapy with cytotoxic therapy.
    3. ECOG performance status of 0-1.
    4. Negative serum pregnancy test in women with childbearing potential (WOCBP) defined as not post-menopausal for 12 months or no previous surgical sterilization, within one week prior to initiation of treatment. WOCBP must be using an adequate method of contraception to avoid pregnancy throughout the study and for up to 12 weeks after the last dose of study drug to minimize the risk of pregnancy. WOCBP must be using an adequate method of contraception to avoid pregnancy throughout the study and for up to 12 weeks after the last dose of study drug to minimize the risk of pregnancy.
    5. A male subject of fathering potential must use an adequate method of contraception to avoid conception throughout the study and for up to 12 weeks after the last dose of study drug to minimize the risk of pregnancy. If the partner is pregnant or breastfeeding, the subject must use a condom.
    6. Patients must sign an informed consent and authorization indicating that they are aware of the investigational nature of this study and the known risks involved.
  • Exclusion criteria:
    1. Concurrent severe and/or uncontrolled medical conditions which could compromise participation in the study such as unstable angina, myocardial infarction within 6 months, unstable symptomatic arrhythmia, uncontrolled diabetes, serious active or uncontrolled infection.
    2. Pregnancy (positive pregnancy test) or lactation.

PHASE 2.

• Name: A phase II, randomized, double-blind study of engineered exosomes with MYC siRNA and overexpression of CD22 in treating participants with Burkitt’s lymphoma.
• Study type: Interventional (clinical trial).
• Estimated enrollment: 90 participants.
• Allocation: Randomized
• Intervention model: Parallel assignment.
• Masking: Double (participant and investigator).
• Primary purpose: Treatment.
• Summary: This phase II trial has the goal to study the safety and efficacy of engineered exosomes loaded with MYC small interference RNA, to suppress the overexpression of MYC oncogene in Burkitt’s lymphoma, and with overexpressed of CD22, to improve the specific delivery of the cargo to lymphoid tissue, therefore having a potential for meaningful single agent antitumor activity in treating participants with Burkitt’s lymphoma refractory to other lines of treatment, in comparison with a conventional chemotherapy (CODOX-M/IVAC + Rituximab).
• Objectives:
  1. Assess the overall response rate with this therapy vs conventional therapy.
  2. Assess the disease control rate (partial response + stable disease) with this therapy vs conventional therapy.
  3. Determine median progression-free survival (PFS) with this therapy vs conventional therapy.
  4. Determine median overall survival (OS) with this treatment vs conventional therapy.
  5. Evaluate optional tissue collection and serum-derived exosomes and circulating-free DNA and RNA showing MYC sequence or siRNA against MYC sequence.
• Outline: The participants will be randomized in a 2:1 ratio to receive exosomes (60 participants or conventional therapy (30 participants). Participants in the exosomes group receive the engineered exosomes intravenously over 15-20 minutes on days 1, 4 and 10. Treatment repeats every 14 days for up to 3 courses in the absence of disease progression or unacceptable toxicity. Participants who respond may continue 3 additional courses. Participants in the conventional therapy group receive a standardized CODOX-M/IVAC + Rituximab regimen. After completion of treatment, participants are followed up at 30 days, then every 3 months for up to 1 year.
• Outcome measures:
  1. Minimal residual disease rate in high-risk patients, modeled using logistic regression.
  2. OS, estimated using the Kaplan-Meier product limit estimator.
  3. PFS, estimated using the Kaplan-Meier product limit estimator.
• Eligibility criteria: idem.

Bureaucratic and safety considerations

Governmental approval:

Since countries uphold requirements and regulations to ensure the safe implementation of medical devices and innovations, the first step towards the application of Vesiprod is the governmental approval of our products. In addition to the regulations provided by the Spanish government, we aim to adhere to additional regulations upheld in the European Union and the United States of America, facilitating further stages of its implementation in future target countries.

Production of exosomes:

In addition to the safety measures to be adopted in the experimental development of the prototype (more information on the Safety webpage), once the exosome-producing cell device is obtained, the production of those exosomes would need to be performed under Good Manufacturing Practice (GMP) standards. Since high amounts of exosomes are to be required, a large-scale production would need to take place on large bioreactors. Different possibilities for that have already been developed [Mendt M et al., 2018].

Security profile:

Despite exosomes being a natural, nontoxic, nonimmunogenic and biodegradable vector for gene targeting, a security profile of the therapeutic exosomes must be assured. For that, multiple analysis may be performed:

Firstly, toxicity and immunogenicity studies on pre-clinical models, as described above. HEK-293T-derived exosomes have already been tested on such conditions, revealing minimal effects in mice [Zhu X et al., 2019]. Secondly, profiling Protein, mRNA and miRNA components of HEK-293T-derived exosomes is required in order to assure that they are safe for use as therapeutics. A characterization of such features have already been performed using mass spectrometry techniques, proteomics and microarrays [Li J et al., 2016]. In this study, certain oncogenic and immunogenic molecules (such as Src and Raf Kinase) were found in low amounts both as protein and mRNA in HEK-293T-derived exosomes. Despite the low amount of those compounds, their presence should be taken into account, especially in the dosage of exosomes. However, trespassing the device to another cell line such as 293F cell line could diminish that pathogenic risk.

Finally, after the finalization of the cell line development, a Master Cell Bank consisting of 20 vials at 5x106 cells/vial needs to be obtained and frozen. Previous tests including mycoplasma test, cell line viability test and surface expression marker testing would be performed.

Environmental impact:

A final challenge that Vesiprod faces upon implementation is the environmental impact of the product. For the future production of Vesiprod on a larger scale, we have planned to use robust materials that can be used to ensure a long lifetime of its parts, avoiding any unnecessary use of single-use products, to reduce its impact to the environment. In the case that single-use products are necessary, biodegradable plastics and recycled materials will be used. Finally, to reduce the environmental impact of the biotechnological production during escalation processes, the production process could be optimized by diversifying substrate sources, reducing by-products formation, and optimizing resource usage.

Conclusion

To conclude, we envision for Vesiprod to be implemented as a research weapon used by the pharmaceutical industry in the field of therapeutics development, being used to treat a vast number of diseases. After therapeutic products are developed using our kit and they obtain governmental approval, they could be purchased by the public health system and private institutions, making medical providers and patients all over the world its indirect and final end-users. To achieve this proposed implementation there are hurdles to overcome and risks to be taken into account, including legislation, certifications, data regulation, safety considerations, preclinical and clinical trials, and environmental impact.

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