Intra-articular Polyacrylamide Hydrogel in Gonarthrosis

The OLE was aimed to assess long-term safety and efficacy of one and two courses of IA HBISA in patients with knee osteoarthritis.

HBISA (polyacrylamide hydrogel) endoprosthesis of synovial fluid NOLTREX™ is intended for the symptomatic treatment of adult patients with osteoarthritis (OA) reducing pain and improving mobility.

The aim of the 6-month OLE was to evaluate the long-term safety and efficacy of one and two courses of IA Polyacrylamide hydrogel with silver ions in patients with knee osteoarthritis who had received at least one IA injection of NOLTREX™ and completed the visit 5 in the IA/PAAG-SI/OA/2019 study.

In OLE patients who had received a course of treatment (one or two weekly intra-articular injections of 4.0 NOLTREX™ depending on the stage of OA and the clinical response to treatment) in the parent study might receive a single repeat course of NOLTREX™ at the visits 1/2 or 3/4 when clinically indicated. The WOMAC was the primary outcome measure.

Eligibility Criteria:
Inclusion Criteria:

* Men and women over 50 years of age;
* Provision of signed informed consent form;
* Patients met ACR classification criteria for knee osteoarthritis (pain in the knee and at least three of the following: age \>50 years, stiffness \<30 min, crepitus, bony tenderness, bony enlargement and no palpable warmth);
* OA grades 2 and 3 on the Kellgren-Lawrence scale with the predominant involvement of the medial tibiofemoral region of the knee joint;
* Patients from the NOLTREX™ group of the parent study (IA/PAAG-SI/OA/2019) who completed all (5) study visits

Exclusion Criteria:

1. Pregnancy and breastfeeding;
2. History of trauma or surgery on the target knee joint;
3. Instability of the target knee joint;
4. Microcrystalline arthropathies (according to the history and taking into account clinical manifestations);
5. History of systemic inflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.);
6. Seronegative spondyloarthritis and reactive arthritis;
7. Increased rheumatoid factor;
8. Increased uric acid \> 360 µmol/l;
9. Intra-articular injection into the target knee joint:

   * hyaluronates - within 12 months prior to patient enrollment in the study;
   * other synovial fluid endoprostheses (except for NOLTREX™ in the IA/PAAG- SI/OA/2019 study) within 24 months;
   * glucocorticoids - within 1 month before enrollment in the study;
   * NSAIDs - intra-articular injection at any time in the history.
10. Systemic pain medications (NSAIDs, opioid analgesics) within 1 week prior to Visit 0;
11. Effusion in the target joint;
12. The presence of inflammation or infection in the target joint, synovitis;
13. The need for continuous use of glucocorticoids in any dosage form;
14. Use of paracetamol within 48 hours prior to Visit 0;
15. A positive blood test result for one or more of the following infections: HIV, hepatitis B and C, syphilis;
16. Severe liver disease, defined as an increase in one of the following: ALT, AST, alkaline phosphatase, total bilirubin, GGT more than 3 times the upper limit of normal;
17. Kidney disease with a glomerular filtration rate as assessed by the Cockcraft-Gault formula less than 60 mL/min/1.73 m2 (stages III-V chronic kidney disease \[CKD\]);
18. Clinical manifest coxarthrosis;
19. Severe decompensated chronic or acute diseases and other conditions or other causes that, in the investigator's opinion, may prevent the patient from participating in the study or affect the study results ;
20. Participation in any other clinical trial except that IA/PAAG-SI/OA/2019 within 90 days prior to enrollment in the OLE.