Transforming OPAT Therapy: A New Route for Antibiotics**
Antibiotics treat bacterial infections. Many antibiotics are poorly absorbed after ingestion and hence must be given by intramuscular injection or infusion. Intramuscular injections are usually given in the buttocks or large muscles of the thigh. Infusions require administration in a vein. If the treatment course is just for a few days, an intravenous catheter is typically placed in the forearm. If longer antibiotic therapy is prescribed, e.g. for a week or more, a long intravenous catheter, known as a PICC line, is placed. PICC stands for peripherally inserted central catheter. PICC lines are long hollow catheters of about 2ft long that are inserted in a vein of the upper arm and extend to the inlet of the heart. Patients have PICC lines for the duration of the antibiotic administration, which may last up to several months. Because intramuscular and intravenous drug administration (placing and starting an IV) are considered invasive procedures that carry risk, they are generally limited by law to be performed by certified healthcare professionals. Certified healthcare professionals include EMTs, nurses and physicians. Intramuscular and intravenous antibiotic treatment have associated risks and high costs, and may cause burdensome discomfort.
The Challenge of Subcutaneous Delivery
Subcutaneous delivery of high-volume drugs like antibiotics requires that medication be optimized, adequately diluted and given slowly, preferably over two hours or longer.
- Physics: High-volume subcutaneous drug delivery requires the slow administration of drug volume to allow the drug to diffuse. In case of antibiotics, 4mL is needed for the lowest doses and 10-20mL for the highest. This is much more than can be given by rapid injection. If subcutaneous antibiotics were given rapidly, the drug would not fit in the subcutaneous space. Tissue would break open, resulting in bruising, bleeding and pain.
- Biology: The sensitive subcutaneous space requires products optimized for this route of administration. Pharmaceutical solutions for subcutaneous delivery cannot be acid or alkaline and the drug itself cannot cause irritation.
- Concentration: Too high a drug concentration may result in a reaction.
In order to give larger volumes of a diluted drug solution slowly over two hours or more, a pump is required. Following the development of novel precision pump technology five years ago, scPharmaceuticals began work on the sc2Wear™ Infusor with the goal of developing a small, wearable pump for use by patients or lay caregivers, following training.
Taking the PICC Out of Antibiotic Treatment
PICC lines became a necessary evil of outpatient treatment with injectable antibiotics. It was the best of poor options. PICC lines are associated with rare but serious complications including:
- Irregular heartbeat
- Deep vein thrombosis
- Infection at the site of insertion
- Bloodstream infection, which may require hospitalization
PICC lines also have significant associated costs including:
- PICC line placement
- Verifying PICC line placement by X-ray or ultrasound
- Daily drug administration/infusion by or under the supervision of a certified healthcare professional. Since Medicare doesn’t cover home infusion services for patients with PICC lines, Medicare patients need to make daily trips to infusion service centers, extend their hospital stays or be admitted to a rehabilitation facility for the sole purpose of getting intravenous antibiotics.
The sc2Wear™ Infusor is designed to eliminate the need for a PICC line by enabling treatment with the full strength of an intravenous course by PICC line, but without the need for a certified healthcare professional.
In March 2016, scPharmaceuticals announced an important milestone in achieving this goal. Optimized subcutaneous delivery resulted in antibacterial efficacy equivalent to intravenous administration.
Expanding Antibiotic Options
Taking the PICC line out of antibiotic therapy may represent one of the biggest improvements in antibiotic therapy for serious infections. However, there is an opportunity to do more. Outpatient infusions are typically limited to once a day for the simple reason that it is not possible to travel to an infusion center twice a day, or more. However, some antibiotics are rapidly removed from the blood stream. This is called a short elimination half-life. Having a short half-life means that the drug needs to be administered multiple times a day, for example every 12, 8, 6 or even 4 hours. If the antibiotics can be sufficiently concentrated and are stable in solution in the sc2Wear™ Infusor, the pump can be placed once a day to deliver multiple doses. This treatment approach would offer tremendous advantages over multiple intravenous administrations. The sc2Wear™ Infusor may enable twice a day administration of certain antibiotics typically given once a day by intravenous infusion, facilitating treatment of more serious infections.
The sc2Wear™ Infusor may also enable FDA approval of antibiotics that have never been available in the United States. Certain antibiotics that have proven to be safe and effective in use in countries in Europe and Asia could be developed for use in the US with the help of the sc2Wear™ Infusor. When first developed, some of these products did not appear to offer advantages over antibiotics already available. However, in the face of increasing resistance, many experts would welcome these products in the US.
In the future, the sc2Wear™ Infusor may facilitate the development of new antibiotic alternatives for use in the US, expanding the antibiotic options for serious infections.
**CAUTION: Investigational Product – Limited by Federal Law to Investigational Use.