Citations

Interest in using gene therapy to treat osteoarthritis (OA) is growing and a number of clinical trials have been initiated. This commentary identifies three intersecting areas that need to be addressed for the field to move forward expeditiously. The first relates to lowering the cost of manufacturing clinical grade viral vectors, addressing various aspects of their deployment, and overcoming immune barriers to dosing and re-dosing. The second area requires an improved understanding of the pathophysiology of OA, including its stratification by endotype and phenotype. Coupled to the development of reliable biomarkers, this will enable the creation of personalized gene therapies, facilitate patient selection, and aid the identification of additional molecular targets. Moreover, progress in the early diagnosis of OA will enable administration of gene therapeutics at a stage when they are most likely to be successful. Finally, important issues with regard to financing and regulation are discussed. Top line data from two pivotal Phase III clinical trials are expected to be released this year. The findings from these trials will exercise considerable influence on the future development of the field.

ABSTRACT Our study aimed to develop a novel, reproducible, minimally invasive turkey knee osteoarthritis (OA) model and evaluate whether intra‐articular hyaluronan (HA) alone or combined with purified exosome product (PEP) attenuates OA‐related functional and structural deterioration. OA was induced arthroscopically by transection of the anterior and posterior cruciate ligaments with resection of the anterior horn of the medial meniscus. Animals received intra‐articular injections of saline, HA, or PEP + HA at postoperative 2–5 weeks. Gait was assessed at 4, 8, and 12 weeks, and cartilage degeneration, subchondral bone sclerosis, osteophyte formation, synovial fibrosis, heterotopic ossification, and meniscal integrity were evaluated by quantitative CT and histology at week 12. Compared with saline, HA improved lameness, preserved cartilage glycosaminoglycan content, and reduced meniscal rupture, subchondral bone sclerosis, and periarticular heterotopic ossification. PEP + HA provided additional benefits, including prolonged stance phase, reduced synovial fibrosis, and greater chondroprotection than HA alone, while plantar pressure variables, subchondral bone remodeling, and patellar osteophytes did not differ between HA and PEP + HA. This turkey model reliably produces human‐like OA changes and enables longitudinal functional and structural assessment. Intra‐articular HA mitigated OA progression, and the addition of PEP conferred incremental joint protection.

ABSTRACT This manuscript summarizes over 30 years of research that began with the novel concept of using intra‐articular gene transfer to treat joint diseases. A notable milestone in this journey was the first‐in‐human transfer of an exogenous gene to a joint, accomplished by the ex vivo delivery of cDNA encoding the interleukin‐1 receptor antagonist (IL‐1Ra) to joints of patients with rheumatoid arthritis. Responding to lessons learned from this study and the prevailing clinical landscape we next developed an in vivo gene delivery system based on adeno‐associated virus (AAV) with osteoarthritis (OA) as the target disease. The safety and efficacy of this vector, sc‐rAAV2.5IL‐1Ra, was demonstrated in the joints of rats and horses leading to a successful IND application to the FDA. In this clinical trial (ClinicalTrials. gov Identifier: NCT02790723) sc‐rAAV2.5IL‐1Ra was injected at escalating doses into the knee joints of nine patients with OA who were followed for 1 year. This trial met its primary outcome measure, safety, and demonstrated that sustained expression of transgenic IL‐1Ra was possible after a single injection of the vector. Patient‐reported outcomes improved, but without a control group it is not possible to determine the influence of a placebo effect. This and other unresolved matters are addressed in a recently‐completed Phase Ib trial (ClinicalTrials. gov Identifier: NCT05835895). Beyond OA, sc‐rAAV2.5IL‐1Ra has potential therapeutic value in a variety of degenerative, inflammatory, fibrotic and autoimmune conditions. More generally, gene therapy holds much promise in the field of regenerative medicine, including regenerative orthopaedics. Trial Registration: (ClinicalTrials. gov Identifier: NCT02790723, NCT05835895).

Background: Adeno-associated viruses (AAVs) are widely used vectors for in vivo gene therapy, but their standard storage at −80 °C limits deployment in regions lacking ultracold infrastructure. Strategies enabling stable AAV storage at higher temperatures are needed to support global distribution. Methods: Nine AAV serotypes were lyophilized in simple sucrose-based buffers. Post-lyophilization vector integrity was assessed by measuring in vitro transduction efficiency using a luciferase reporter in cell-based assays. Stability of selected serotypes (AAV2.5 and AAV6) was further evaluated over 8 weeks under varying storage temperatures. Results: Lyophilization in sucrose preserved transduction activity for all tested serotypes (AAV1, AAV2, AAV2.5, AAV3, AAV4, AAV5, AAV6, AAV8, AAV9, and AAVrh10). Notably, AAV2, AAV2.5, and AAV6 exhibited 3- to 6-fold increases in transduction, an effect attributable to the sucrose excipient rather than the lyophilization process itself. Long-term stability of lyophilized vectors varied by serotype, temperature, and vial-seal integrity. AAV6 retained full activity for at least 8 weeks when stored at 4 °C or −20 °C. Conclusions: AAV vectors can be effectively lyophilized in simple sucrose solutions, enabling storage at standard −20 °C freezer temperatures while maintaining functional activity. Optimization of lyophilization buffers and excipients may further extend AAV stability at higher temperatures, improving feasibility for global gene therapy deployment.

Abstract The Fracture Nonunion Symposium presented at the 2024 Orthopaedic Trauma Association Basic Science Focus Forum featured invited speakers who discussed current perspectives on this topic. Clinical approaches, diagnostic advancements, basic science perspectives, and novel treatment strategies were discussed. This symposium was curated to highlight this common and challenging clinical problem faced by orthopaedic and musculoskeletal practitioners from around the globe.

When long bones fracture, healing occurs spontaneously in about 90% of cases, while the remaining 10% result in non-union, presenting significant clinical challenges. The standard treatment for non-unions is autologous bone grafting, but this approach has limitations, including high complication rates, donor site morbidity, and limited graft availability. An alternative strategy involves using growth factors to promote bone regeneration, with recombinant bone morphogenetic protein-2 (rBMP-2) being the most common. Although effective, rBMP-2 requires supra-physiological doses that cause inflammation, poor bone quality, and severe side effects. Our previous work suggests that genetic delivery of BMP-2 may offer more controlled healing. We aim to develop a more effective therapy for non-unions using adeno-associated viral vectors. By lyophilizing the vector onto a scaffold, we also aim to increase treatment potency, reduce leakage, and improve transduction using cryoprotectant buffers.AAV6-GFP-Luciferase was used to compare the activity of AAV6 stored at −80°C versus lyophilized in cryoprotectant buffer. A rat critical-sized defect model was employed, as described in [1]. For standard storage, AAV was added to the collagen sponge before implantation into a 5mm defect. For lyophilization, AAV was mixed with cryoprotectant, loaded onto the sponge, and lyophilized. Rats were imaged at 7- and 10-days using IVIS. To assess therapeutic relevance, the experiment was repeated with AAV6-BMP2-IL1Ra, implanted into 5mm femoral defects on collagen sponges, with healing monitored by X-ray every 4 weeks (continuing through 12-weeks post-operation).The reporter and therapeutic vectors showed improved transduction efficiency with lyophilization. The reporter vector exhibited higher transgene expression at days 7 and 10. This boost in expression either remained significant through 4 weeks or continued to show better signal at that time, correlating with improved healing seen in the X-rays (Fig. 2).Preliminary data suggest that lyophilization could reduce the therapeutic dose of AAV needed for treating osseous nonunion with a bicistronic vector. Lyophilization offers various benefits: enhanced transduction efficiency, improved stability of the gene product at logistically feasible conditions, and reduced off-target effects due to less AAV leakage from the implantation site. While in vivo experiments with AAV6-BMP2-IL1Ra are ongoing, these findings warrant further investigation into lyophilized AAV therapies for this application.For any figures or tables, please contact the authors directly.

Abstract Bone morphogenetic proteins ‐2 and ‐7 (BMP‐2 and BMP‐7) are effective in treating large bone defects, but the required doses are high, resulting in side effects and elevated costs. Previously, this work has demonstrated that a chemically modified messenger RNA (cmRNA) coding for BMP‐2 induced rapid and reliable healing until consolidation in a bone segmental defect in rats. Here, this work shows that the simultaneous transfer of BMP‐2 and BMP‐7 cmRNAs to stem cells leads to increased osteogenic gene expression, extracellular matrix deposition, and mineralization, compared to single or sequential delivery of these cmRNAs. Using a murine model of ectopic ossification, this work finds that dual BMP‐2/BMP‐7 cmRNA delivery using collagen‐hydroxyapatite scaffolds, designed specifically for bone repair, ensured local BMP‐2 and ‐7 expression with abundant osteogenesis in the absence of adverse effects. This confirms the superior osteogenic potency achieved by local, controlled dual delivery of cmRNAs encoding BMP‐2 and BMP‐7, further enhancing the potential of this highly translatable technology for promoting bone healing.

Abstract Objective This study explores and documents the patient experience during the prodrome phase of migraine. Background Migraine attacks can be divided into four stages: the prodrome (or premonitory phase), the aura, the headache phase, and postdrome. Qualitative data on the range of symptoms during the prodrome and their timing relative to headache onset are sparse. Prodromal symptoms may predict the onset of migraine headache pain and provide a clinically useful benchmark for initiation of treatment early in an attack before pain begins. Design/Methods Eligible participants with a clinician‐confirmed diagnosis of migraine and at least one prodromal symptom were consented, screened, and then participated in 60‐min interviews. The interview guide included open‐ended questions to elicit spontaneous reports and specific probes about prodromal symptoms based on a clinician‐established list. A theory approach was used to analyze the qualitative data collected in interviews to identify key themes and gather insights; data were analyzed using ATLAS.ti. Results Data collection for this study occurred from March 8, 2022, to May 16, 2022. Twenty interviews were conducted, and analyses demonstrated that concept saturation was achieved. Participants reported 36 unique prodromal symptoms, and each participant experienced a mean of 13 symptoms (standard deviation [SD] = 6.6) and a median of 11 symptoms (interquartile range [IQR] = 7.8–17.0) during the prodrome phase. The most commonly reported prodromal symptoms were nausea ( n = 17/20, 85%), fatigue/tiredness ( n = 16/20, 80%), sensitivity to light ( n = 13/20, 65%), neck pain/stiffness ( n = 12/20, 60%), and dizziness/vertigo/light‐headedness ( n = 10/20, 50%). Of the symptoms reported by at least four participants ( n ≥ 4/20, 20%), neck pain/stiffness was rated most bothersome (8.9 out of 10) and sensitivity to light was rated most severe (8.5 out of 10). Almost 40% of all symptoms reported occurred less than 2 h before the start of migraine headache. Of the commonly reported symptoms, nausea (0.8h), sensitivity to light (1.0 h), and dizziness/vertigo/lightheadedness (2.0 h) began closest to headache onset; fatigue/tiredness (4.0 h) and neck pain/stiffness (4.8 h) were the most remote from headache onset. Conclusion This study identified frequently reported prodromal symptoms, with participants commonly reporting that a migraine headache would follow their experience of prodrome within a 1‐ to 6‐h window. Characterizing the prodrome experience may improve measurement strategies for the burden of migraine and create opportunities to treat during the prodromal phase to prevent the onset of moderate or severe headaches.

Osteoarthritis (OA) is a major global health problem with no disease-modifying therapies. Interleukin-1 (IL-1) is a critical cytokine associated with the pathophysiology of OA and can be inhibited by IL-1 receptor antagonist (IL-1Ra). Here, we tested the delivery of a gene therapeutic encoding the human IL-1Ra to the knee in a phase 1, open-label clinical trial that enrolled nine patients with radiographic knee OA. The IL-1Ra gene was delivered by a self-complementary (sc)–recombinant adeno-associated virus (rAAV) serotype 2.5 (sc-rAAV2.5IL-1Ra) by intra-articular injection into an index knee at one of three doses: low [1 × 10 11 viral genomes (vg)], mid (1 × 10 12 vg), or high (1 × 10 13 vg). The primary outcome was safety. There were no serious adverse events (AEs) related to sc-rAAV2.5IL-1Ra. Two AEs occurred that were possibly related to the vector. Both were effusions with increased pain and resolved with conservative treatment. sc-rAAV2.5IL-1Ra did not cause changes in vital signs, physical findings, or clinical laboratory measures. Less than 1% of the injected dose of sc-rAAV2.5IL-1Ra vg was detected in circulation after 1 day and was cleared within a week. Titers of neutralizing antibodies to AAV2.5 rose in serum and synovial fluid. In all cases, IL-1Ra concentration increased in the synovial fluid, and IL-1Ra concentrations remained elevated after 1 year. Baseline pain and function scores improved during the study. Therefore, we found that intra-articular gene therapy with sc-rAAV2.5IL-1Ra was safe. The sustained increase in local IL-1Ra in human knee joints supports the further clinical examination of this therapy to provide therapeutic benefit in OA.