Losmapimod does not reduce cardiovascular events in patients with acute myocardial infarction

Discontinued Drugs for the Treatment of Cardiovascular Disease from 2016 to 2018

Cardiovascular drug research and development (R&D) has been in active state and continuously attracts attention from the pharmaceutical industry. However, only one individual drug can eventually reach the market from about the 10,000 compounds tested. It would be useful to learn from these failures when developing better strategies for the future. Discontinued drugs were identified from a search performed by Thomson Reuters Integrity. Additional information was sought through PubMed, ClinicalTrials.gov, and pharmaceutical companies search. Twelve compounds discontinued for cardiovascular disease treatment after reaching Phase I-III clinical trials from 2016 to 2018 are detailed in this manuscript, and the reasons for these failures are reported. Of these, six candidates (MDCO-216, TRV027, ubenimex, sodium nitrite, losmapimod, and bococizumab) were dropped for lack of clinical efficacy, the other six for strategic or unspecified reasons. In total, three candidates were discontinued in Phase I trials, six in Phase II, and three in Phase III. It was reported that the success rate of drug R&D utilizing selection biomarkers is higher. Four candidate developments (OPC-108459, ONO-4232, GSK-2798745, and TAK-536TCH) were run without biomarkers, which could be used as surrogate endpoints in the 12 cardiovascular drugs discontinued from 2016 to 2018. This review will be useful for those involved in the field of drug discovery and development, and for those interested in the treatment of cardiovascular disease.

p38 mitogen activated protein kinase mediates cardiac Na+/H+ exchanger inhibition induced by Sildenafil

Since the original description as potent antianginal compounds, phosphodiesterase 5A inhibitors have continuously increased their possible therapeutic applications. In the heart, Sildenafil was shown to protect against an ischemic insult by decreasing cardiac Na⁺/H⁺ exchanger (NHE1) activity, action that was mediated by protein kinase G. p38 mitogen activated protein kinase (p38MAPK) activation was described in cardiac ischemia, but its precise role remains elusive. It has been shown that p38MAPK is activated by protein kinase G (PKG) in certain non-cardiac tissues, while in others modulates NHE1 activity. Current study was aimed to seek the role of p38MAPK in the Sildenafil-triggered pathway leading to NHE1 inhibition in myocardium. Rat isolated papillary muscles were used to evaluate NHE1 activity during intracellular pH recovery from an acidic load. Protein kinases phosphorylation (activation) was determined by western blot. Sustained acidosis promoted NHE1 hyperactivity by enhancing Ser703 phosphorylation, effect that was blunted by Sildenafil. p38MAPK inhibition reversed the effect of Sildenafil on NHE1. Activation of p38MAPK, by Sodium Arsenite or Anisomycin, mimicked the inhibitory effect of Sildenafil on the exchanger. Consistently, Sildenafil induced p38MAPK phosphorylation/activation during acidosis. Neither Sildenafil nor p38MAPK inhibition affected extracellular signal-regulated kinases 1/2 phosphorylation, kinases upstream NHE1. Furthermore, inhibition of NHE1 after p38MAPK activation was precluded by preventing the activation of protein phosphatase 2A with Okadaic Acid. Taken together, these results suggest that activation of p38MAPK is a necessary step to trigger the inhibitory effect of Sildenafil on cardiac NHE1 activity, thorough a mechanism that involves protein phosphatase 2A-mediated exchanger dephosphorylation.