Recent Patents on CNS Drug Discovery (Discontinued) - Volume 9, Issue 3, 2014

With the advances in antiretroviral (ARV) therapy, patients with Human Immunodeficiency Virus (HIV) infection are living longer, however, some patients encounter co- morbidities which sometimes require treatment. Therefore, during the treatment with ARV drugs these patients could take several recreational drugs (e.g. amphetamines, hallucinogenes, opiates, or alcohol) with a possible development of drug-drug interactions (DDIs). In particular, Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs/NtRTIs) are mainly excreted through the kidney and are not substrates of the cytochrome P450 or P-glycoprotein, therefore the DDIs during this treatment are minimal. In contrast, the other ARV drugs (i.e. non-nucleoside reversetranscriptase inhibitors, Protease inhibitors, Integrase inhibitors, chemokine receptor 5 antagonists and HIV-fusion inhibitors) are an important class of antiretroviral medications that are frequent components of HAART regimens but show several DDIs related to interaction with the cytochrome P450 or P-glycoprotein. In this paper we will review data concerning the possibility of DDI in HIV patients treated with ARV and taking recreational drugs.

Primary hyperparathyroidism (HPT) is the main cause of hypercalcemia and the most common parathyroid glands disease. The diagnosis is easy in patients with hypercalcemia and elevated PTH serum level. Minimally invasive parathyroidectomy (PTx) represents the treatment of choice for symptomatic patients, leading to several advantages, including immediate normalization of hypercalcemia and significant improvement of bone mineral density, cardiovascular dysfunctions, neuropsychological symptoms and quality of life. Secondary and tertiary HPT are relatively common complications in patients with chronic kidney disease (CKD) or advanced kidney failure, and in kidney transplant recipients who did not achieve complete calcium/phosphate metabolism normalization, respectively. The drugs available for patients with secondary HPT, and to treat hyperphosphatemia include non-calcium-containing phosphate binder, calcitriol analogues, calcimimetic agents, or a combination of two or more drugs. Although recent studies report that PTx significantly improves survival also in patients with CKD and severe secondary HPT, the indications for surgery are not yet well established. Subtotal or total PTx with or without autotransplantation are the surgical options for treating all patients with secondary HPT. Total PTx leads to a faster reduction in serum calcium level and normalization of PTH, but the risk of hypoparathyroidism is higher than after subtotal PTx. Further studies are needed to confirm the usefulness of the drugs currently recommended, and others will have to be tested in the near future.

Liver growth factor (LGF) is a hepatic mitogen purified by our group in 1986. In the following years we demonstrated its activity both in “in vivo” and “in vitro” systems, stimulating hepatocytes mitogenesis as well as liver regeneration in several models of liver injury. Furthermore, we established its chemical composition (albumin-bilirubin complex) and its mitogenic actions in liver. From 2000 onwards we used LGF as a tissue regenerating factor in several models of extrahepatic diseases. The use of Liver growth factor as a neural tissue regenerator has been recently protected (Patent No US 2014/8,642,551 B2). LGF administration stimulates neurogenesis and neuron survival, promotes migration of newly generated neurons, and induces the outgrowth of striatal dopaminergic terminals in 6-hidroxydopamine-lesioned rats. Furthermore, LGF treatment raises striatal dopamine levels and protects dopaminergic neurons in hemiparkinsonian animals. LGF also stimulates survival of grafted foetal neural stem cells in the damaged striatum, reduces rotational behaviour and improves motor coordination. Interestingly, LGF also exerts a neuroprotective role both in an experimental model of cerebellar ataxia and in a model of Friedrich´s ataxia. Microglia seem to be the cellular target of LGF in the CNS. Moreover, the activity of the factor could be mediated by the stimulation of MAPK´s signalling pathway and by regulating critical proteins for cell survival, such as Bcl-2 and phospho-CREB. Since the factor shows neuroprotective and neurorestorative effects we propose LGF as a patented novel therapeutic tool that may be useful for the treatment of Parkinson´s disease and cerebellar ataxias. Currently, our studies have been extended to other neurological disorders such as Alzheimer’s disease (Patent No: US 2014/0113859 A1).

Chronic migraine is the most frequent and disabling complication of migraine. To date, only two drugs have been specifically analysed for the treatment of chronic migraine, topiramate and onabotulinumtoxin A, and in the evidence-based medicine categories, they have achieved level of evidence I and as such, a grade of recommendation A according to current guidelines. Following the PREEMPT paradigm, pericranial intramuscular onabotulinumtoxin A injections show a good efficacy and safety in chronic migraine patients, both in phase III randomized clinical trials and in a pooled data analyses. Onabotulinumtoxin A injections reduce the number of days of headache and migraine, they reduce the consumption of triptans and disability, and improve the quality of life of migraine patients. For these reasons, onabotulinumtoxin type A is an option as valid as topiramate for the treatment of chronic migraine.

Antidepressants can relief human depression and reduce human depressive symptoms. Nevertheless, some undesired clinical events, such as suicide have been emerging. As for 2004, the US and European regulatory agencies began implementing verification programs to assess the influence on suicidal behavior from the use of antidepressants such as selective serotonin reuptake inhibitors (SSRIs). With the increasing number of reported cases, several newly developed antidepressants were faced with withdrawal from the markets. Despite unclear cause of suicide, researches focusing on revealing the relationship between efficacy and toxicities of antidepressants have been initiated in China and US. To deal with these undesired clinical consequences, new initiatives and revolutionary ideas have been proposed and verified. Hopefully, therapeutic efficacies and outcomes by different types of antidepressant treatments can be improved for clinical trials in future.