Karyopharm Therapeutics Inc. is a clinical-stage pharmaceutical company focused on discovery and development and subsequent commercialization of novel first-in-class drugs directed against nuclear transport and related targets for the treatment of cancer and other major diseases.
Our scientific expertise is focused on understanding the regulation of intracellular communication between the nucleus and the cytoplasm. We have discovered and are developing novel, small molecule Selective Inhibitor of Nuclear Export, or SINE, compounds that inhibit the nuclear export protein XPO1. These SINE compounds represent a new class of drug candidates with a novel mechanism of action that have the potential to treat a variety of diseases in areas of unmet medical need. Our SINE compounds were the first oral XPO1 inhibitors in clinical development.
Our lead drug candidate, selinexor (KPT-330), is an XPO1 inhibitor being evaluated in multiple late stage clinical trials in patients with relapsed and/or refractory hematological and solid tumor malignancies.
XPO1 mediates the export of over 220 different cargo proteins, including the vast majority of tumor suppressor proteins. We believe that no currently approved or current clinical-stage experimental cancer drug candidates are selectively targeting the restoration and increase in the levels of multiple tumor suppressor proteins in the nucleus.
Our other drug candidates in development include oral verdinexor (KPT-335) as an anti-viral agent, as well as a treatment for cancer in companion dogs, oral KPT-350 as a treatment for neurological, inflammatory and autoimmune conditions, KPT-8602 as a treatment for relapsed/refractory multiple myeloma and our oral dual PAK4/NAMPT inhibitor, KPT-9274, for the treatment of patients with advanced solid malignancies or non-Hodgkin’s lymphoma.
XPO1-inhibiting SINE compounds that we have discovered and developed to date, including selinexor, have the potential to provide a novel targeted therapy that enable tumor suppressor proteins to remain in the nucleus and promote apoptosis of cancer cells and we believe that our SINE compounds have the potential to provide therapeutic benefit in a number of additional indications, including autoimmune and inflammatory diseases, wound healing, HIV and influenza.
In addition to our SINE compounds, we also investigate XPO1 cargo proteins and their role in the cell cycle and cell division. As part of this investigation, we have identified several XPO1 cargo proteins whose inhibition leads to the selective death of cancer cells. One of the XPO1 cargo proteins that we identified was p21-activated kinase 4, or PAK4. PAK4 is member of the PAK family of kinases that includes 6 proteins, PAK1-6. PAK4-6 belong to a growth-promoting sub-family. PAK4 is a signaling protein regulating numerous fundamental cellular processes, including intracellular transport, cellular division, cell shape and motility, cell survival, immune defense and the development of cancer. PAK4 interacts with many key signaling molecules involved in cancer such as beta-catenin, CDC42, Raf-1, BAD and myosin light chain. Based on this biology, we used our drug discovery and optimization expertise to identify small molecule modulators of PAK4. Our PAK4 allosteric modulators have shown broad evidence of anti-cancer activity against hematological and solid tumor malignant cells while showing minimal toxicity to normal cells in vitro. In mouse and rat xenograft studies, our PAK4 inhibitors given orally have shown evidence of anti-cancer activity and tolerability. To our knowledge, we are the only company with a pre-IND allosteric, PAK4 specific inhibitor.
Recently, we identified an additional target for our clinical candidate KPT-9274 known as NAMPT (Nicotinamide phosphoribosyltransferase; also known as PBEF or Visfatin). NAMPT is a pleiotropic protein with intra- and extra-cellular functions as an enzyme, cytokine, growth factor, and hormone that can be found in complex with PAK4 in the cell. NAMPT is of interest as an oncology target because it catalyzes the rate-limiting step in one of the two intracellular salvage pathways that generate nicotinamide adenine dinucleotide, or NAD. NAD is a universal energy- and signal-carrying molecule involved in mitochondrial function, energy metabolism, calcium homeostasis, antioxidation, and paradoxically generation of oxidative stress, gene expression, immunological functions, aging, and cell death.
In addition, we are investigating a SINE compound for cancer in companion dogs, both as a surrogate model for human malignancies and as a potential treatment for cancers in dogs. It is widely known that canine lymphomas respond to chemotherapy similarly to their human counterpart (human NHL) and display a comparable genetic profile. Lymphomas are one of the most common tumors in pet dogs. Lymphoma in dogs is very aggressive and, without treatment, the tumors are often fatal within weeks. The majority of dog lymphomas are DLBCL and most of the others are T-cell lymphomas. Given the similarities between dog and human lymphomas, prior to initiating clinical trials of selinexorin humans, we investigated a closely-related, orally available SINE, verdinexor, in dogs with lymphomas.
Verdinexor has received a Minor Use / Minor Species, or MUMS, designation from the Center for Veterinary Medicine, or CVM, of the FDA for the treatment of lymphomas in canines.