Extend Biosciences aims to develop safe and effective therapies that can be self-administered by the patient at home. The company has multiple compounds in development both internally and with external partners.
Our lead program is a long-acting PTH(1-34) for the treatment of hypoparathyroidism. This rare disease is characterized by inappropriately low circulating levels of parathyroid hormone (PTH). PTH is a key regulator of calcium and phosphorous homeostasis in the kidneys, movement of calcium from the skeleton, and production of the active form of vitamin D in the kidneys. Hypoparathyroidism is most commonly caused by inadvertent removal of the parathyroid glands during neck surgery, and less commonly by autoimmune diseases and rare genetic disorders. A lack of continuous PTH production leads to hypocalcemia (low blood calcium), which if left untreated causes persistent muscle cramps, paresthesias (or “pins and needles” feelings), seizures, and irregular heart rhythms. Additionally, patients suffer from cognitive disorders such as anxiety, depression, memory problems and general “brain fog”. Long-term complications of hypoparathyroidism can include kidney stones, kidney damage, cataracts, calcification of soft tissues and abnormalities in bone remodeling as well as death.
To date, no formal guidelines exist for the therapeutic management of hypoparathyroidism. Conventional treatment (calcium and active vitamin D supplements) focuses on maintaining serum calcium levels while preventing the risk of hypercalciuria, or excessive urinary calcium secretion, which can lead to kidney failure. Until the approval of recombinant full-length PTH(1-84) by the FDA in early 2015 (Natpara®, Shire), there were no approved hormone replacement therapies available for hypoparathyroidism, making it the last remaining endocrine deficiency for which the missing hormone was not an approved therapy. Our long-acting PTH is a subcutaneously administered PTH derivative with an attractive value proposition. The pharmacokinetic profile our D-VITylated PTH(1-34) conjugate mimics the physiological levels of PTH, thereby returning and maintaining serum calcium and phosphate levels within the normal range.
EXT418 for Cachexia
Following close behind our lead program is our long-acting ghrelin peptide for cachexia, a complex metabolic syndrome characterized by involuntary weight and muscle loss that affects >1 million patients/year. Cancer and other devastating chronic diseases such as congestive heart failure and AIDS are often coupled with cachexia. Studies have shown that cancer patients who have cachexia respond poorly to chemotherapy, are at a greater risk of infection and have a reduced life expectancy. In fact, it is estimated that at least 30% of cancer patients die from cachexia, not cancer. Currently there are no FDA-approved therapies to treat cachexia. Ghrelin is a hormone made by the body that increases appetite and stimulates muscle growth. Ghrelin has already been shown to safely abrogate the affects of cachexia in numerous animal models as well as in many human trials. However, because of its short half-life, ghrelin must be administered 3-4 times daily or using an intravenous infusion in order to see these effects. This is simply not practical for patients with chronic diseases. Extend Biosciences’ D-VITylation platform technology is truly enabling for this short-lived peptide as it increases the half-life and improves the bioavailability of the peptide in the body. Reversing the effects of cachexia will significantly improve a cancer patient’s quality of life and chance of survival, as well as decrease the need for hospitalizations, resulting in reduced healthcare costs.
Extend Biosciences also has two other peptides under development, and several biotechnology and pharmaceutical partners that are developing improved versions of their own peptide-based therapies using our technology. These programs serve as external validation of our technology and may generate longer-term licensing arrangements and revenue to Extend Biosciences.