In 2017, there will be approximately 161,360 new cases of prostate cancer and about 25% will die from the disease according to the American Cancer Society. In the U.S., 5% of men with prostate cancer will have metastatic cancer and up to 30% of men with high-risk, localized prostate cancer will develop metastatic cancer following initial therapy. The median survival of patients with metastatic prostate cancer ranges from 3.2-4.5 years. For these men, 1st line therapy is androgen deprivation therapy, or medical castration. Although most will initially respond, nearly all these patients will progress to metastatic castration resistant prostate and have a poor prognosis with an average survival of 1.5 years. New 2nd line hormonal agents, like XTANDI (enzalutamide) and ZYTIGA (abiraterone/prednisone) have resulted in an additional four to five months of average survival, but again, nearly all men on these agents will develop progressive metastatic prostate cancer.
Agents that target tubulin have been shown to be the most effective cytotoxic chemotherapy for the treatment of metastatic prostate cancer. Tubulin, a component of microtubules, is required for cancer cell replication and to shuttle the androgen receptor into the nucleus where the receptor stimulates genes for cancer cell proliferation. Docetaxel and cabazitaxel are examples of FDA-approved chemotherapy drugs that are given intravenously (IV) that target tubulin to treat metastatic prostate cancer. Although effective, the challenges for this class of chemotherapy agents, also known as taxanes, include that they must be given IV and that the cancer cells develop resistance to taxanes in a variety of ways: Cancer cells may (i) express multidrug resistance proteins which pump the taxane chemotherapy meant to kill the cancer cells, out of the cancer cells; (ii) develop tubulin mutations so taxanes are no longer able to bind to the mutated tubulin; and/or (iii) overexpress beta-tubulin so that there is plenty of tubulin present for cell replication even if some tubulin is bound by taxanes. There are also serious safety concerns with IV taxanes which include serious hypersensitivity reactions, myelosuppression and neurotoxicity such as peripheral neuropathy and muscle weakness.
Based on over 28 peer-reviewed scientific publications, VERU-111 is a novel small molecule that is a New Chemical Entity (NCE) that has been optimized to be an orally dosed tubulin targeting chemotherapy agent. VERU-111 binds to a different site from taxanes on tubulin called the “colchicine binding site.” VERU-111 has high oral bioavailability; does not interact with multiple drug resistance proteins so it cannot be pumped out of the cancer cell; minimal drug to drug interactions especially not metabolized by CYP3A4 and has high activity against many tumor types including prostate, breast and ovarian cancers. Furthermore, it has activity against cancers that have become resistant to taxanes, vinca alkaloids and doxorubicin. In preclinical studies, VERU-111 has less neurotoxicity and leucopenia compared to other tubulin targeting agents.