Background: Standard care in severe SARS-CoV-2 pneumonia complicated by severe dyspnea and respiratory failure, consists of symptom reduction, ultimately supported by mechanical ventilation. Patients with severe SARS-CoV-2, a prominent feature of COVID-19, show several similar symptoms to Critical Asthma Syndrome (CAS) patients, such as pulmonary edema, mucus plugging of distal airways, decreased tissue oxygenation, (emergent) exhaustion due to severe dyspnea and respiratory failure. Prior application of elective phosphodiesterase (PDE)3-inhibitors milrinone and enoximone in patients with CAS yielded rapid symptomatic relief and reverted the need for mechanical ventilation, due to their bronchodilator and anti-inflammatory properties. Based on these observations, we hypothesized that enoximone may be beneficial in the treatment of patients with severe SARS-CoV-2 pneumonia and prominent CAS-features. Methods: In this case report enoximone was administered to four consecutive patients (1 M; 3 F; 46-70 y) with emergent respiratory failure due to SARS-CoV-2 pneumonia. Clinical outcome was compared with three controls who received standard care only. Results: After an intravenous bolus of enoximone 20 mg followed by 10 mg/h via perfusor, a rapid symptomatic relief was observed: two out of four patients recovered within a few hours, the other two (with comorbid COPD GOLD II/III) responded within 24-36 h. Compared to the controls, in the enoximone-treated patients respiratory failure and further COVID-19-related deterioration was reverted and mechanical ventilation was prevented, leading to reduced hospital/ICU time. Discussion: Our preliminary observations suggest that early intervention with the selective PDE3-inhibitor enoximone may help to revert respiratory failure as well as avert mechanical ventilation, and reduces ICU/hospital time in patients with severe SARS-CoV-2 pneumonia. Our findings warrant further research on the therapeutic potential of PDE3-inhibition, alone or in combination with other anti-COVID-19 strategies.

Background. The population of uncontrolled asthma patients represents a large therapeutic burden. The PDE3-inhibitor enoximone is a strong and quick bronchodilator and is known to successfully treat life-threatening bronchial asthma (status asthmaticus). Translational mice models showed anti-inflammatory effects when PDE3 was targeted. Methods. Here, we investigated the effectiveness of PDE3-inhibitor enoximone as oral treatment for chronic asthma in a real-life off-label setting. Investigational use of PDE3-inhibitor enoximone: 51 outpatients (age 18–77) with chronic asthma were followed using off-label personalized low doses of the PDE3-inhibitor enoximone. Duration of treatment was 2–8 years. Results. Four groups could be distinguished as follows: The first group includes patients who use enoximone as an add-on, because it helps them in maintaining a better general wellbeing; they still use their traditional medication (n = 5). The second group consists of patients who use enoximone and were able to phase down their traditional medication without deterioration of their asthma symptoms (n = 11). The third group comprises patients who were able to discontinue their traditional medication and use only enoximone without deterioration of their asthma symptoms (n = 24). The last one has patients who, after having used enoximone for some time, saw their symptoms disappear and now use no medication at all, not even enoximone (n = 11). All patients reported improvement or at least alleviation of their asthma symptoms. All patients reported a better quality of life and greater drug compliance. Conclusion. The evaluation shows that PDE3-inhibitor enoximone is a viable alternative for or addition to current asthma therapeutics, as both add-on and stand-alone, considerably reducing the use of LABAs/SABAs/ICS, with no or negligible side effects. Additional studies are advisable.