A subretinal injection technique and implementations thereof

Abstract

The present disclosure provides an injection technique for subretinal delivery of a substance into one or more predetermined sites in subretinal area of a human subject using a specific reduced intraocular pressure and delivery pressure. The injection technique facilitates the delivery of a larger number of cells to subretinal areas without the risk of reflux.

Description

A SUBRETINAL INJECTION TECHNIQUE AND IMPLEMENTATIONS THEREOFFIELD OF INVENTION

[0001] The present disclosure broadly relates to the field of surgical techniques for ocular therapies. The present disclosure particularly relates to an injection technique for subretinal delivery of a substance.BACKGROUND OF THE INVENTION

[0002] Subretinal injection is a preferred delivery technique for various novel ocular therapies. It offers multiple advantages over intravitreal delivery, including higher transfection levels with a lower viral dose for gene therapy, a reduced risk of systemic and ocular immune response for cell therapy, its precision and efficient delivery of the target substances. Subretinal injection involves inserting a trocarcannula system, performing a pars plana vitrectomy, followed by a retinotomy and finally creating an initial subretinal bleb, using balanced saline solution. The bleb is created prior to delivery of substances into the subretinal area, to avoid wastage of the administered substances, especially when dosages are of smaller volumes. However, there is still a leakage of the administered substances (reflux) into the vitreous cavity, potentially during injection and after cannula removal, which is a major concern. A study using intraoperative optical coherence tomography (iOCT) has suggested that reflux can be as high as 60% of the planned dose, with a mean of 36% (Gregori, Ninel Z. MD; Lam, Byron L. MD; Davis, Janet L. MD. Intraoperative Use of Microscope-Integrated Optical Coherence Tomography for Subretinal Gene Therapy Delivery. Retina 39():p S9-S12, October 2019. \ DOI: 10.1097 / IAE.0000000000001646). Particularly, when the administered substances are cells, the reflux and release of cells into the vitreous cavity can induce an immune response and / or subsequently lead to the formation of epiretinal membranes, some of which require a pars plana vitrectomy for removal of the epiretinal membranes.

[0003] Therefore, there is a need in the art to develop a method of efficient delivery of the intended substances into the subretinal area without having a reflux, to prevent said risks.SUMMARY OF INVENTION

[0004] In an aspect of the present disclosure, there is provided an injection technique for subretinal delivery of a substance into one or more predetermined sites in subretinal area of a human subject, comprising: (a) performing a vitrectomy to access the retina; (b) identifying one or more predetermined sites for injection in subretinal area; (c) reducing intraocular pressure; and (d) advancing a microdose injector connected to a needle and filled with the substance into the subretinal area to reach the predetermined site, and delivering the substance, wherein, the intraocular pressure is reduced to be in a range of 8 to 14 mm Hg.

[0005] In another aspect of the present disclosure, there is provided a method of treatment of an ocular condition in a human subject in need thereof, comprising the injection technique as described herein.

[0006] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the disclosed subject matter, nor is it intended to be used to limit the scope of the disclosed subject matter.BRIEF DESCRIPTION OF DRAWINGS

[0007] The following drawings form a part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.

[0008] Figure 1 depicts Fellow eye comparison: Study eye showed 13.3 letter improvement vs. 3.3 letter improvement in untreated fellow eye at 12 months, according to embodiments herein in 4 subjects.DETAILED DESCRIPTION OF THE INVENTION

[0009] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.Definitions

[0010] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0011] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0012] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”.

[0013] Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of elements or steps but not the exclusion of any other element or step or group of elements or steps.

[0014] The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.

[0015] The term “w / w,” as used herein, refers to percentage by weight, relative to the weight of the total composition, unless otherwise specified.

[0016] Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merelyfor convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.

[0017] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0018] Subretinal injection is a critical delivery technique for advanced ocular therapies, including cell therapy and gene therapy, offering significant advantages over intravitreal delivery such as higher transfection levels, reduced immune response risk, and precise therapeutic delivery. However, as discussed in the background, there is a need in the art to develop a technique to deliver substances into the subretinal area without reflux of the delivered substances into the vitreous cavity. Normally, during a vitrectomy surgery, the intra ocular pressure (IOP) is kept at 30 mm Hg during the entire surgery. Sometimes, the IOP may be reduced to about 25 mm Hg, specially while injecting some drugs / products (like triamcinolone acetonide or Trypan Blue) into the vitreous cavity. The main concern at this high-pressure of 25 / 30 mm Hg is the reflux of the product from the subretinal space into the vitreous cavity. Additionally, there is also an increased risk of foveal tear in the eyes of the patients or subjects.

[0019] In a routine setting, subretinal surgery is mostly performed to remove blood from the subretinal space (using a drug called tissue plasminogen activator / tPA). During this surgery, the reflux of the drug into the vitreous cavity is not taken into consideration, and therefore the IOP is typically not reduced to less than 25 / 30 mm Hg.

[0020] The present invention provides an injection technique for subretinal delivery of substances, particularly retinal pigment epithelium cells, into predetermined sites in the subretinal area of human subjects. The technique comprises performing avitrectomy to access the retina, identifying predetermined injection sites, reducing intraocular pressure to 8-14 mm Hg, and advancing a microdose injector connected to a needle into the subretinal area to deliver the substance under a pressure of 8-14 PSI. This specific combination of parameters significantly reduces reflux of administered substances into the vitreous cavity, enables delivery of larger numbers of therapeutic cells to target sites, prevents post-injection complications, and can be applied to treat various ocular conditions including Geographic Atrophy, dry Age-related Macular Degeneration, and inherited retinal diseases. The technique may utilize standard surgical instruments familiar to retinal surgeons while automating the most sensitive injection steps to ensure consistency and repeatability across different surgeons and clinical settings. Maintaining the pressure in a specific range for delivery is important as reducing pressure to very low or very high may damage vision of the eye. The clinical data as provided herein demonstrates that the disclosed injection achieves very minimal reflux while delivering therapeutic efficacy (average 13.3 letter ETDRS improvement at 12 months) with no serious adverse events.Injection technique:

[0021] Embodiments herein provide an injection technique or a method for subretinal delivery of a substance into one or more predetermined sites in the subretinal area of a human subject.

[0022] In an embodiment of the present disclosure, there is provided an injection technique for subretinal delivery of a substance into a predetermined site in subretinal area of a human subject, comprising: performing a vitrectomy to access retina; identifying the predetermined site for injection; reducing the intraocular pressure; and advancing a microdose injector connected to a 38G / 2mm tip needle and filled with the substance into the subretinal area to reach the predetermined site, and delivering the substance.

[0023] In an embodiment, the human subject has an ocular condition.

[0024] In another embodiment of the present disclosure, the human subject has an ocular condition selected from Geographic Atrophy (GA), or Secondary to DryAge-related Macular Degeneration (d-AMD) or Retinal Degenerations or Inherited Retinal Diseases or Glaucoma or any other ocular condition where treatment with cell therapy or gene therapy is deemed possible.

[0025] The term “sub-retina” or “subretina” is referred to the area that is beneath the retina in the eye.

[0026] The term “subretinal delivery” as used herein refers to the process of introducing therapeutic substances into the subretinal space.

[0027] The term “subretinal area” as used herein refers to the anatomical space beneath the neurosensory retina.

[0028] Then term “advancing” as used herein refers to the controlled insertion and positioning of the needle-injector assembly through the retinal tissue to reach the target subretinal location.

[0029] In an embodiment, the injection technique as disclosed herein, reduces reflux of the delivered substance into the vitreous cavity of the eye in a human subject.Vitrectomy:

[0030] The injection technique, according to the embodiments herein, comprises performing a vitrectomy to access the retina.

[0031] The term “vitrectomy” as used herein refers to a type of eye surgery used to treat problems associated with retina and / or vitreous present in the eye.

[0032] In an embodiment of the present disclosure, the vitrectomy is performed to access the retina and is preceded by preparing the eye to be operated.Preparing the eye:

[0033] Embodiments herein include preparing the eye to be operated prior to vitrectomy.

[0034] In an embodiment of the present disclosure, preparing the eye to be operated comprises the steps of, administering a general or local anesthesia, dilating pupils using at least one dilating agent, cleaning the eye and the surrounding area using a cleansing solution, and washing the eye with balanced salt solution.

[0035] In an embodiment of the present disclosure, the at least one dilating agent is selected from tropicamide, phenylephrine, or combinations thereof; optionally along with homatropine. In another embodiment of the present disclosure, the at least one dilating agent is 1% tropicamide, 2.5% or 5% or 10% phenylephrine, or 2% homatropine. In yet another embodiment of the present disclosure, the at least one dilating agent is 1% tropicamide, or 5% phenylephrine.

[0036] In an embodiment of the present disclosure, the cleansing solution is 5% povidone iodine.Performing vitrectomy

[0037] In an embodiment of the present disclosure, the prepared eye is ready for performing vitrectomy.

[0038] In an embodiment of the present disclosure, the vitrectomy is an anterior or posterior vitrectomy, via pars plana vitrectomy.

[0039] The term “pars plana vitrectomy” as used herein refers to a commonly employed technique in vitreoretinal surgery that enables access to the posterior segment (like retina) for treating certain conditions.

[0040] In an embodiment of the present disclosure, the vitrectomy is micro incision pars plana vitrectomy (23G / 25G / 27G) comprising the steps of applying a speculum and inserting a trocar-cannula system into the vitreous cavity by creating sclerotomy incisions.

[0041] The term “pars plana vitrectomy refers to a surgical approach accessing the vitreous cavity through the pars plana (the flat part of the ciliary body), typically using a trocar-cannula system with multiple ports.

[0042] The term “trocar-cannula system” as used herein refers to a system acting as a portal in the surgical procedure, which involves interventional placement of tubes and drainage where instruments, tubes or drains are advanced to the predetermined site through a fixed cannula or hollow tube namely the trocar.

[0043] In an embodiment of the present disclosure, the trocar-cannula system is inserted in the quadrants of the eye, by creating sclerotomy incisions.

[0044] The term “sclerotomy incisions” refers to small surgical openings made through the sclera (white part of the eye) to accommodate the trocar-cannula system.

[0045] In an embodiment of the present disclosure, the infusion cannula is placed in the inferotemporal quadrant, and two superior cannulas are placed in the superior quadrants. In other embodiments, the infusion cannula may be placed in quadrants other than inferotemporal quadrant. In one embodiment, the infusion cannula may be placed in inferonasal quadrant.

[0046] In an embodiment of the present disclosure, the pars plana vitrectomy (PPV) is selected from single port, two-port, or three-port PPV, preferably a three port PPV, followed by inducing a posterior vitreous detachment. In another embodiment of the present disclosure, the pars plana vitrectomy is three-port PPV.

[0047] In an embodiment of the present disclosure, the technique optionally comprises injecting intravitreal triamcinolone acetonide (IVTA), during vitrectomy to visualize the posterior vitreous body.

[0048] The term “triamcinolone acetonide” refers to a non-soluble steroid diluted with a balanced salt solution, used to enable optimal visualization of the vitreous body during surgery.

[0049] The term “posterior vitreous detachment” refers to the separation of the vitreous gel from the retinal surface, which may be induced surgically to facilitate retinal access.Identifying the predetermined site for injection and reducing the intraocular pressure

[0050] The injection technique, according to the embodiments herein, comprises identifying one or more predetermined sites in the subretinal area for injection or delivery of the substance.

[0051] In an embodiment of the present disclosure, the predetermined site is identified after visualizing the retina.

[0052] The term “predetermined site”, as used herein, refers to a region in the subretinal area where the substance is to be delivered. In an embodiment, the predetermined sites are in a range of 1-3 sites in the subretinal area.

[0053] The injection technique, according to the embodiments herein, comprises reducing the intraocular pressure. The term “intraocular pressure” or eye pressure or IPO refers to the pressure of the fluid inside of the eye.

[0054] In an embodiment of the present disclosure, the intraocular pressure is reduced to be in a range of 8 to 14 mm Hg in step (c) of the injection technique as disclosed herein. In another embodiment, the intraocular pressure is reduced to be in a range of 8-13 mm Hg, 8-12 mm Hg, 9-13 mm Hg, 9-12 mm Hg, 8-11 mm Hg, 9-11 mm Hg, 9-10 mm Hg, or 8-10 mm Hg, preferably 10mm Hg.Delivery through a microdose injector

[0055] The injection technique, according to the embodiments herein, comprises delivery of the substance into the predetermined site in the subretinal area of a human subject using a microdose injector. The term “delivery” has been used interchangeably with the term “injection” or “injecting”.

[0056] The term “microdose injector”, as used herein refers to an injector specifically designed for low volume ophthalmic injection into the subretinal area.

[0057] In an embodiment of the present disclosure, the microdose injector is connected to a needle. In another embodiment, the front end of the microdose injector is connected to a needle.

[0058] In an embodiment of the present disclosure, the needle connected to the microdose injector has a gauge size in a range of 35 to 41, preferably the gauge size is 38. In an embodiment of the present disclosure, the needle has a gauge size of 38 or the needle is a 38 -gauge needle.

[0059] In an embodiment of the present disclosure, the microdose injector is machine operated. In another embodiment, the back of the microdose injector is connected to a VFC (viscous fluid control) tube and the tube is connected to the console of the vitrectomy machine.

[0060] In an embodiment of the present disclosure, the microdose injector connected to a needle is filled with the substance prior to injection.

[0061] In an embodiment of the present disclosure, the substance is selected from cells, fluids, gene therapy products and drugs, or combinations thereof, preferably cells. In another embodiment of the present disclosure, the substance is cells.

[0062] In an embodiment of the present disclosure, the cell is selected from retinal pigment epithelium cells (RPE), photoreceptors, any cells of retinal origin, stem cells, or combinations thereof. In another embodiment of the present disclosure, the cells are retinal pigment epithelium cells (RPE).

[0063] The term “retinal pigment epithelium cells (RPE)” refers to a suspension of post-mitotic cells just outside the neurosensory retina, which functions both as a selective barrier and a vegetative regulator of the overlying photoreceptor layer.

[0064] In an embodiment of the present disclosure, the dosage of the cells is in a range of 0.5xl05to 3xl05in 100 to 300 pl, preferably the dosage of the cells is 2xl05cells in 200 pl. In another embodiment, the cells are filled in the microdose injector at a predetermined dosage, prior to injection, wherein the dosage of the cells is in the range of 0.5xl05to 3xl05in 100 to 300 pl, preferably the dosage of the cells is 2x105cells in 200 pl.

[0065] In an embodiment of the present disclosure, the microdose injector connected to a 38G needle and filled with the substance is advanced into the subretinal area to reach the predetermined site to deliver the substance. In another embodiment of the present disclosure, the microdose injector connected to a 38G needle and filled with the RPE cells is advanced into the subretinal area to reach the predetermined site to deliver the cells.

[0066] In an embodiment of the present disclosure, the substance is delivered into the predetermined site in subretinal area under a pressure of 8-14 PSI. In another embodiment, the substance is delivered into the predetermined site in subretinal area under a pressure of 8-13 PSI, 9-13 PSI, 9-12 PSI, 8-11 PSI, 9-11 PSI, 10-11 PSI, preferably under a pressure of 10 PSI.

[0067] In an embodiment of the present disclosure, the substance is released as a single or multiple bolus into the predetermined site. The term “bolus” refers to single, concentrated dose of a drug or a substance.

[0068] In an embodiment of the present disclosure, the substance is delivered to one or more predetermined site. In another embodiment, the substance is delivered to more than one or multiple predetermined sites. In yet another embodiment there are 1-3 predetermined sites for injection. In one of the embodiments, the substance is delivered as a single or multiple bolus into more than one predetermined site. Post delivery procedure

[0069] In an embodiment of the present disclosure, the predetermined site in the subretinal area is visualized optionally through intraoperative optical coherence tomography (iOCT), post injection or delivery or release of the substance or the cells.

[0070] The term “intraoperative optical coherence tomography (iOCT)” refers to real-time imaging technology integrated into the surgical microscope that provides cross-sectional views of retinal structures during surgery.

[0071] In an embodiment of the present disclosure, a partial or complete fluid air exchange may be performed after the injection. In another embodiment of the present disclosure, a partial fluid air exchange may be performed after injection.

[0072] The term “fluid air exchange” refers to a surgical procedure where vitreous fluid is replaced with air or gas, which may be performed partially or completely after substance delivery.

[0073] In an embodiment of the present disclosure, administration of antibiotics, steroids, or combinations thereof, may be performed post injection.

[0074] In one embodiment, the injection technique significantly reduces the risk of reflux of the administered substances into the vitreous cavity of the eye.

[0075] In another embodiment, the injection technique facilitates the delivery of a larger number of cells to the predetermined site in subretinal area. In a further embodiment, the injection technique can be used for delivery of any cell type of the eye.

[0076] In yet another embodiment, the injection technique does not cause post injection complications or adverse events.

[0077] In one embodiment, the injection technique achieves visual acuity improvements of at least 10 ETDRS letters in treated subjects.Method of treatment

[0078] In an embodiment of the present disclosure, there is provided a method of treatment of an ocular condition in a human subject in need thereof, comprising the injection technique as described herein. In an embodiment of the present disclosure, the ocular condition is any condition which may be treated using cell therapy or gene therapy. In another embodiment, the ocular condition is selected from Geographic Atrophy (GA), Secondary to Dry Age-related Macular Degeneration (d-AMD), Retinal Degenerations, Inherited Retinal Diseases, or Glaucoma.

[0079] Although the subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined.EXAMPLES

[0080] The disclosure will now be illustrated with following examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to beunderstood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary.Materials

[0081] The materials used in the present study were procured from various sources. The retinal pigment epithelium cells were an in-house product (Eyecyte-RPE™ cells). However, a person of skill in the art will understand that RPE cells from any source can be used.Example 1: Injection technique for delivery of a substance (Retinal Pigment Epithelium cells) in the subretinal area1.1 Preparing the eye for vitrectomy:

[0082] The eye to be operated was prepared prior to the vitrectomy. General or local anesthesia was administered, followed by the dilation of the pupils using appropriate dilating agents, such as a combination of 1% tropicamide and 5% phenylephrine with or without 2% homatropine. The eye and the surrounding area were cleaned with 5% povidone iodine solution and a few drops instilled into the eye (unless the patient is allergic), left undisturbed for a minute. Further, the eye was washed with balanced salt solution (procured from Alcon) and was ready for vitrectomy.1.2 Performing pars plana vitrectomy:

[0083] The speculum was applied, followed by insertion of a 23 / 25 / 27G trocarcannula system in the 3 quadrants of the eye, by creating sclerotomy incisions. The infusion cannula was placed in the inferotemporal quadrant, and the superior two cannula were placed in the superior quadrants of the eye. The 3-port pars plana vitrectomy (PPV) was performed followed by inducing a posterior vitreous detachment. Intravitreal triamcinolone acetonide may be used to visualize the retina, if required.1.3 Preparing and loading the Retinal Pigment Epithelium cells for delivery:

[0084] The cells were prepared as per a proprietary protocol of the Applicant, and a predetermined dosage of cells (0.5xl05- 3.0 x 105) were suspended in 0.1-0.3 mL of balanced salt solution. The prepared cells were loaded into the microdose injector (procured from MedOne, US; Ref#3275) by aspirating the entire volume (0.1 -0.3 mL) of the cells, connected to the VFC tubing connected to the console of the vitrectomy machine using a cannula of the 18G Vasofix, without the needle (procured from B Braun). The microdose injector was connected to a 38-gauge needle (procured from MedOne, US) and the empty space was primed, prior to cell loading.1.4 Delivering the Retinal Pigment Epithelium cells into the predetermined site below the retina or sub-retinal injection:

[0085] The predetermined site(s) was identified (by avoiding vessels, and beingl-2 discs away from the fovea), and the intraocular pressure was reduced to 10 mm Hg. The needle attached to the microdose injector was inserted into the retina, making a retinotomy, to reach the predetermined site in the subretinal area. The loaded or filled cells were released into the site under a pressure of 8 to 14 PSI. The loaded cells were released as a single bolus into a single predetermined site. Optionally, an intraoperative optical coherence tomography (iOCT) was carried out to visualize a local retinal detachment, followed by a partial fluid air exchange. The sclerotomy incisions were closed, followed by administration of subconjunctival antibiotics, and steroids, and the eye was patched. The patient was instructed to lie supine during the postoperative period for at least for 4-6 hours and was followed up for 12-months post-surgery, to track any adverse events.Results:

[0086] There was no evident reflux of the delivered cells (retinal pigment epithelium cells) using the injection technique of the present disclosure. A dosage of 0.5xl05to 3xl05cells was delivered without a reflux, as compared to the existing techniques. Furthermore, the patients did not report any adverse events even months after the surgery.Example 2: Phase 1 Safety Study of Subretinal RPE Cell Delivery Using the Disclosed Injection Technique2.1. Study Design and Materials:

[0087] A Phase 1, open -label, dose-escalation safety study was conducted to evaluate the disclosed injection technique for subretinal delivery of RPE cells in human subjects with Geographic Atrophy. The study comprised three cohorts with escalating cell doses: Cohort 1 (l><105cells), Cohort 2 (2*105cells), and Cohort 3 (3*105cells). Each cohort included 3 subjects (n=9 total). The retinal pigment epithelium cells were suspended in 100-300 pL of balanced salt solution and loaded into a microdose injector (MedOne, Cat3275) connected to a 38-gauge needle. The injection technique was performed by six different surgeons across nine surgeries to demonstrate repeatability.2.2. Surgical Procedure:

[0088] The disclosed injection technique was implemented as explained in Example 1. The safety results that show Ocular TEAEs are depicted in Table 1.Table 1: Safety results

[0089] No Serious Adverse Events (SAEs) were reported across all cohorts. Ocular adverse events were mild and resolved without intervention, demonstrating the safety profile of the disclosed technique.

[0090] Efficacy Results: Visual acuity improvements were measured using ETDRS letter scores from baseline to most recent visit and the results are depicted in Table 2.Table 2: Efficacy Results

[0091] Key Efficacy Outcomes:

[0092] Average improvement: 14.8 letters over 6 months (8 patients completing 6 months).

[0093] 12-month follow-up: 13.3 letter improvement (4 patients completing 12 months).

[0094] Structural / anatomical improvement corresponding to vision changes identified in some patients post 6 and 12 months.

[0095] Fellow eye comparison: Study eye showed 13.3 letter improvement vs. 3.3 letter improvement in untreated fellow eye at 12 months (refer Figure 1).

[0096] When compared with techniques such as, complicated supra choroidal delivery method, used in prior arts, the present technique did not show any SAEs across phase one trials, whereas prior art technique reports some SAEs. Moreover, the present technique shows 14.8 letter change in 6 patients over 6 months and a 13.3 letter improvement in 4 patients over 12 months, which is significantly advanced as compared to other known techniques which report 6.2 letter improvement stable at 3 years. This shows significant advancement over prior art techniques.Advantages of the present disclosure

[0097] The present disclosure provides an injection technique for subretinal delivery of a substance with the following advantages:1. It significantly reduces the risk of reflux of the administered substances into the vitreous cavity of the eye.2. It can facilitate the delivery of a larger number of cells to the predetermined site in subretinal area.3. The technique can be used for delivery of any cell type of the eye.4. The technique does not cause any post inj ection complication / adverse event which is largest issue in subretinal delivery of cells.5. The technique shows consistency when performed by different surgeons.6. The technique can be used for treatment of different types of ocular conditions.7. The 13.3 letter improvement at 12 months significantly exceeds results reported for other RPE cell therapies using conventional injection techniques.

Claims

I / We Claim:

1. An injection technique for subretinal delivery of a substance into a predetermined site in subretinal area of a human subject, comprising: a) performing a vitrectomy to access the retina;b) identifying one or more predetermined sites for injection in subretinal area;c) reducing intraocular pressure; andd) advancing a microdose inj ector connected to a needle and filled with the substance into the subretinal area to reach the predetermined site, and delivering the substance,wherein, the intraocular pressure is reduced to be in a range of 8 to 14 mm Hg2. The injection technique as claimed in claim 1, and wherein the substance is delivered into the predetermined site under a pressure of 8-14 PSI.

3. The technique as claimed in claim 1, wherein, the intraocular pressure is reduced to be in a range of 9-11mm Hg.

4. The technique as claimed in claim 1, wherein the substance is released as a single or multiple bolus into the predetermined site.

5. The technique as claimed in claim 1, wherein the needle connected to the microdose injector has a gauge size in a range of 35 to 41.

6. The technique as claimed in claim 1, wherein the microdose injector is machine operated.

7. The technique as claimed in claim 1, wherein the substance is selected from cells, fluids, gene therapy products and drugs, or combinations thereof.

8. The technique as claimed in claim 7, wherein the cell is selected from retinal pigment epithelium cells (RPE), photoreceptors, any cells of retinal origin, stem cells, or combination thereof.

9. The technique as claimed in claim 1, wherein the vitrectomy is an anterior or posterior vitrectomy, via pars plana vitrectomy.

10. The technique as claimed in claim 9, wherein the vitrectomy is micro incision pars plana vitrectomy (23G / 25G / 27G) comprising the steps of applying aspeculum and inserting a trocar-cannula system into the vitreous cavity by creating sclerotomy incisions.

11. The technique as claimed in claim 9 or 10, wherein the pars plana vitrectomy is selected from single port, two-port, or three-port, followed by inducing a posterior vitreous detachment.

12. The technique as claimed in claim 1, wherein the technique optionally comprises injecting intravitreal triamcinolone acetonide, post vitrectomy to visualize the retina.

13. The technique as claimed in claim 1, wherein the technique comprises an optional step of visualizing the predetermined site in the retina through intraoperative optical coherence tomography (iOCT).

14. The technique as claimed in claim 1, wherein the technique comprises an optional step of performing a partial or complete fluid air exchange after delivery.

15. The technique as claimed in claim 1 , wherein the technique further comprises administering antibiotics, steroids, or combinations thereof.

16. A method of treatment of an ocular condition in a human subject in need thereof, comprising the injection technique as claimed in claim 1.

17. The technique as claimed in claimed in claim 1 or the method as claimed in claim 16, wherein the human subject has Geographic Atrophy (GA), Secondary to Dry Age-related Macular Degeneration (d-AMD), Retinal Degenerations, Inherited Retinal Diseases, Glaucoma or any other ocular condition.

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