Additional Study Information: The purpose of this study is to research and evaluate safety and effectiveness of the administration of bone marrow mesenchymal stem cell (bmMSC) derived extracellular vesicles product, DB-3Q, the study drug for perianal fistulizing Crohns disease. The study will enroll up to 36 participants across multiple sites. Your participation in this study will be approximately 6 months. The investigational product is experimental and has not been approved by the US Food and Drug Administration (FDA). The experimental study drug is a biologic product which is purified from the bone marrow of a healthy well-screened individual. It contains no cells, instead it is made up of pro-immune, anti-inflammatory and pro-regenerative molecules. The study drug is a liquid given by a subcutaneous (SQ, just under the skin) injection directly to the site of the perianal fistula or intravenous (IV, in a vein) infusion. If you qualify, you will then be randomly assigned (like a flip of a coin) to receive either study drug or a placebo (saline). A placebo has no active ingredient and is made to look like the study drug. The placebo for this study is sterile salt water (saline). You will not know if you will receive study drug or placebo. If you are in the first treatment group, you will receive a 15 mL (about 1 tablespoon) injection on Day 1. If you are in the second treatment group, you will receive a 30 mL (about 2 tablespoons) injection on Day 1. If you are in the third treatment group, you will receive a 30 mL injection and a 100 mL (about 0.5 cup) IV infusion on Day 1. After you leave the hospital, you will need to come in for follow-ups at Week 2, 6, 12, and 18. These visits will include a general and health perianal exam, review for any health or medication changes, paper questionnaires regarding your health, taking your vital signs, a blood sample to do laboratory tests mentioned above, a pelvic MRI to evaluate healing, and a fecal sample to measure calprotectin.