Patient case (clinical description): A 47-year-old woman comes to the office complaining of pain in the calf and knee when she bends down. The pain limits her activity. Her medical history is significant for osteoarthritis, for which she uses nonsteroidal anti-inflammatory drugs (NSAIDs) for the past two years. She is living with her husband and has 3 children. She doesn't smoke but drinks alcohol occasionally. Her vital signs are normal. On physical examination, there is a small effusion in the right knee. The effusion grew a little larger and she developed a tender swelling in the popliteal fossa and calf. Both the pain and swelling worsened as she bent and straightened her knee.

Patient's own account: I'm a 47-year-old woman, married with 3 kids. I don't smoke and I drink occasionally. I went to the doctor because of pain in my calf and knee when I was bending down. This has been limiting my daily activities. I have been diagnosed with osteoarthritis for which I have taken anti-inflammatory drugs for the past 2 years. The doctor saw a small fluid buildup in my right knee. This buildup became a bit bigger and I have a swollen calf. The pain is worse when I bend and straighten my knee.

Clinical trial: A Study Evaluating the Safety and Efficacy of a Second Course of TPX-100 in Subjects Who Previously Received TPX-100 for Patellar Osteoarthritis Involving Both Knees

Eligibility criteria:
Inclusion Criteria:

          1. Previous enrollment in study TPX-100-1

               -  Cruciate and collateral ligament stability as defined by clinical examination

          2. Able to read, understand, sign and date the subject informed consent

          3. Willingness to use only acetaminophen as the primary analgesic (pain-relieving) study
             medication during the injection period and through study day 30. The maximum dose of
             acetaminophen must not exceed 2 grams/day (2000 mg per day).

          4. Willingness to use only hydrocodone or hydrocodone/acetaminophen (e.g. Norco) for
             breakthrough pain through study day 30.

          5. Willingness not to use non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin,
             ibuprofen, naproxen through study day 30.

          6. Female subjects of child bearing potential who are sexually active (non-abstinent)
             must agree to and comply with using 2 highly effective methods of birth control (oral
             contraceptive, implant, injectable or indwelling intrauterine device, condom with
             spermicide, or sexual abstinence) while participating in the study.

        Exclusion Criteria:

          1. "Possibly, probably or definitely" drug-related SAEs in TPX-100-1; severe or ongoing
             "possibly, probably or definitely" related AEs in TPX-100-1.

          2. Contraindication to MRI, including: metallic fragments, clips or devices in the brain,
             eye, or spinal canal; implanted devices that are magnetically programmed; weight > 300
             lbs.; moderate or severe claustrophobia; previous intolerance of MRI procedure

          3. Prior surgery in the knees, excluding procedures for debridement only (no previous
             microfracture procedure)

          4. Joint replacement or any other knee surgery planned in the next 12 months

          5. History of rheumatoid arthritis, psoriatic arthritis, or any other autoimmune or
             infectious cause for arthritis

          6. Knee effusion > 2+ on the following clinical scale:

               -  Zero = No wave produced on downstroke

               -  Trace = Small wave on medial side with downstroke

               -  1+ = Larger bulge on medial side with downstroke

               -  2+ = Effusion spontaneously returns to medial side after upstroke (no downstroke
                  necessary)

               -  3+ = So much fluid that it is not possible to move the effusion out of the medial
                  aspect of the knee screening

          7. Last viscosupplementation (e.g. Synvisc® or similar hyaluronic acid product) injected
             into either knee < 3 months before screening

          8. Last intra-articular knee injection of corticosteroids < 2 months before screening

          9. Use of any steroids (except inhaled corticosteroids for respiratory problems) during
             the previous month before screening

         10. Known hypersensitivity to TPX-100

         11. Known hypersensitivity to acetaminophen or hydrocodone

         12. History of arthroscopy in either knee in the last 3 months before screening

         13. History of septic arthritis, gout or pseudo-gout, of either knee in previous year
             before screening

         14. Clinical signs of acute meniscal tear (locking, new acute mechanical symptoms
             consistent with meniscal tear)

         15. Patellar chondrocalcinosis on X-Ray

         16. Skin problem, rash or hypersensitivity, affecting either knee at the injection site

         17. Bleeding problem, platelet or coagulation deficiency contraindicating, in the doctor's
             opinion, intra-articular injection

         18. Active systemic infection

         19. Current treatment or treatment within the previous 2 years prior to the Screening
             Visit for any malignancy except basal cell or squamous cell carcinoma of the skin,
             unless with specific written permission is provided by the Sponsor's medical monitor

         20. Women of childbearing potential who are pregnant, nursing, or planning to become
             pregnant, and those who do not agree to remain on an acceptable method of birth
             control throughout the entire study period

         21. Participation in other clinical osteoarthritis drug studies, with the exception of
             TPX-100-1, within one year prior to screening

         22. Currently taking Paclitaxel (mitotic inhibitor), natalizumab (anti-integrin monoclonal
             antibody), or any other anti-integrin treatment.

         23. History of significant liver disease or consumption of more than 3 alcoholic drinks a
             day. (Definition of one alcoholic drink: 12-ounces of beer, 8-ounces of malt liquor,
             5-ounces of wine, 1.5-ounces or a "shot" of 80-proof distilled spirits or liquor such
             as gin, rum, vodka, or whiskey).
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 25 Years old.
Subject must be at most 75 Years

Eligibility (NLI label): Contradiction