Effect of bromhexine on clinical outcomes and mortality in COVID-19 patients: A randomized clinical trial

Introduction

The severe acute respiratory syndrome coronavirus 2 (SARS- CoV- 2) disease has emerged as a multifaceted disease with varied pathologies involving multiple organs. The COVID-19 infection can manifest in degrees from a predicted 50% asymptomatic illness, to 20% of cases having severe illness.¹ According to Johns Hopkins University Coronavirus Resource Center, the mortality rates vary between 4.5-16% in the top 10 most affected countries. As of mid-June 2020, the number of deaths surpassed 438,000 individuals throughout the world. The virus can aggravate an inflammation cascade and cause a cytokine storm. This is one of the major mechanisms that can cause the deterioration of the general condition in patients with COVID-19 infection.²

Multiple different therapeutic options like anti-malaria, HIV medications, antivirals, and steroids have been tried with limited results. The most notable was the compassionate use of remedisivir in the setting of COVID-19 infection. The original data initially encouraged the FDA to approve this medication for use in COVID-19 infections, but further clinical trials have not been able to support significant clinical benefit. Currently, no therapeutic agents have been proven to be effective in reducing the mortality and treatment of patients with COVID-19.^3-5

SARS-CoV-2 attaches to the angiotensin-converting enzyme 2 (ACE2) receptor of the host cell via its spike protein. The virus has two pathways in which it can enter the cell, either Endocytosis or Non-endocytosis. Today, the newer viruses tend to use the non-endocytosis pathway which is activated by transmembrane serine protease 2 (TMPRSS2).⁶ Blocking the TMPRSS2 and the non-endocytosis pathway would be an interesting therapeutic option in preventing virus entry into the cell and therefore, treating the disease. Nafamostat and camostat mesylate, medications that are used to treat chronic pancreatitis are potential candidates for blocking virus entry by inhibiting TMPRSS2.^7,8

There is some concern about the low distribution of these drugs in the respiratory system. As shown in Fig. 1, another TMPRSS2 inhibitor with a greater distribution capacity into the lung tissue is bromhexine hydrochloride.^9,10 It is an old over-the-counter medication that has been used for several decades as a mucolytic agent. The current study, an open-label, randomized clinical trial, examined the efficacy of early start of oral bromhexine, in the intensive care unit (ICU) admission, rate of mechanical ventilation, and mortality in patients with COVID-19 pneumonia.

Fig. 1

TMPRSS2 protease system of host cell wall priming viral spike protein and facilitating viral cell entry via ACE2 receptor blocked by bromhexine.

Materials and Methods

Patients were recruited in University Hospital from April 18, 2020, to May 19, 2020. The study was completed on May 28, 2020. Written informed consent was obtained from all study participants. This clinical trial was an open-label, randomized clinical study. Eighty-nine patients with a diagnosis of COVID-19 pneumonia were screened. Eleven of the patients were excluded. [9 not meeting inclusion criteria, 2 declined]. A total of 78 patients were enrolled.

The diagnosis of COVID-19 pneumonia was made by a board-certified pulmonologist based on clinical symptoms and signs, as well as chest CT findings compatible with the COVID-19 pneumonia pattern. Although PCR testing became available within a few weeks following the start of the outbreak, its use was not relied upon for entry into the trial given the lag period for the availability of results and a high number of false-negative results.

The subjects, based on inclusion and exclusion criteria, were randomized (1:1) via balanced block randomization into treatment and non-treatment (standard) groups [39 persons per each group] by epidemiologists of the study. Clinicians and patients were not blind to treatment assignment.

Results

Eighty-nine patients with proven COVID-19 pneumonia were screened. Eleven of the patients were excluded (i.e., 9 not meeting the inclusion/exclusion criteria, 2 declined). A total of 78 patients were enrolled in this randomized clinical trial. They were assigned to either the treatment with the bromhexine group or the standard treatment group in a 1:1 ratio with 39 patients in each arm. No attrition in either arm (Fig. 2)

Fig. 2

Patient enrollment and treatment assignment.

The demographic and disease characteristics of the treatment and standard groups were similar (Table 1). The mean age was 58.4±13.7 years among the treated arm and 61.1 ±16.1 in the standard arm. In terms of gender, 43 (54.4%) were male, and the percentage of males in the treatment and standard groups was 48% and 61%, respectively. No significant difference was noted in the comorbid conditions of diabetes mellitus and hypertension between the treatment and control groups. There was no significant difference in the time-lag of symptom initiation to hospital admission in the treatment (7.7±4.1 days) arm or the standard (8.3±5.8 days) arm (P =0.632). The body mass index (BMI) and APACHE score in both groups were almost identical.

Primary clinical outcome

There was a significant difference in the 28-day mortality, no patient died (0%) in the treatment group, while five patients died (12.8%) in the standard group; P = 0.027 (Fig. 3). Among patients in the treatment arm with bromhexine, two patients were admitted to ICU (5.1%) while in the standard arm, eleven patients (28.2%) were transferred to ICU. There was a significant difference in the ICU admission between the treatment and the standard group (P  = 0.006). Moreover, among patients in bromhexine arm, one patient received mechanical ventilation (2.6%), while in the standard arm nine patients (23.1%) were intubated and underwent mechanical ventilation. There was also a highly significant difference in the intubation and mechanical ventilation between the two groups (P  = 0.007) as shown in Table 2.

Fig. 3

Patient enrollment and primary outcomes.

Table 2. Post-treatment clinical characteristics in patients treated with bromhexine and standard group
Demographic characteristics	Standard group (n=39)	Treatment group (n=39)	P value
Primary outcomes
Mortality, No. (%)	5 (12.8)	0 (0)	0.027d
ICU admission, No. (%)	11 (28.2)	2 (5.1)	0.006b
Mechanical ventilation, No. (%)	9 (23.1)	1 (2.6)	0.007b
Secondary outcomes
Fever, No. (%)	3 (10.0)	0 (0)	0.125d
Cough, No. (%)	12 (40.0)	2 (6.9)	0.003b
Dyspnea, No. (%)	14 (48.3)	1 (3.4)	<0.001b
Lassitude, No. (%)	10 (34.5)	2 (6.9)	0.010b
Myalgia, No. (%)	4 (13.8)	3 (10.3)	0.500d
Headache, No. (%)	3 (10.0)	0 (0)	0.125d
GI symptoms, No. (%)	1 (3.3)	4 (13.8)	0.166d
NLR (IQR)	3.0 (6.3)	1.7 (1.0)	0.052c
Positive CRP, No. (%)	9 (81.8)	0 (0)	<0.001d
LDH U/L mean ±SD	445.3±115.2	363.2±83.6	0.056a
Hospital stay (days), mean ±SD	8.1 ±5.5	7.6 ±3.5	0.587a
Abbreviations: APACHE, acute physiology and chronic health evaluation; Spo2, saturation of peripheral oxygen; GI, Gastrointestinal; NLR, neutrophil-lymphocyte ratio; IQR, interquartile range; CRP, C-reactive protein; LDH, lactate dehydrogenase; ICU, intensive care unit. aIndependent Samples t-test; b Chi-squared test; dFisher's exact test, dCalculated with Mann-Whitney; The values shown were based on the total number of patients who contributed values.

Secondary clinical outcomes

There was also a significant difference in the secondary outcome of this study (Fig. 4). Improvement of cardinal respiratory symptoms such as cough and dyspnea within two weeks among the two groups were assessed: Dyspnea remained in 3.4% in the treatment group vs 48.3% in the standard group P ≤ 0.001 and cough remained in the treatment group 6.9% vs 40.0% in the standard group, P  = 0.003). Similar results for lassitude between the two groups were observed (6.9% vs 34.5%, P  = 0.010). At baseline, there was no significant difference in the frequency of fever, headache, and gastrointestinal symptoms between the two groups.

Fig. 4

Patient enrollment and secondary outcomes.

The patients in the bromhexine group showed improvement in the level of LDH (363.2±83.6 vs. 445.3±115.2; P  = 0.056), NLR [1.7 (1.0) vs. 3.0 (6.3); P =0.052] and CRP [0% vs. 81.8%; P < 0.001)] within two weeks compared to the standard group (Table 2).

There was no significant difference in the length of stay in the hospital [from randomization to discharge] between the two groups (treatment 7.6±3.5 days and standard 8.1±5.5 days; P  = 0.587).

Discussion

The data presented in this clinical trial confirmed that the early-onset treatment with oral bromhexine 8 mg three times a day not only effectively mitigated the respiratory symptoms, but also significantly decreased the rate of ICU admissions, intubation, mechanical ventilation, and mortality in COVID-19 disease. This is a very significant finding that has a direct correlation with the outcome of the disease. The difference in the number of deaths in the bromhexine arm (0 death) vs. the standard arm (5 deaths, 12.8%) is reflective of the efficacy of this medication in reducing mortality when started early in the course of the disease.

COVID-19 infection, like the original SARS and MERS diseases, has a strong affinity to the lung parenchyma. The clinical manifestations vary from a simple cough to full-blown acute respiratory disease (ARDS). Hypoxemia and oxygen desaturation, which have often been unresponsive to the usual therapeutic measures have led the patients to ICUs which often includes initiation of ventilation support and death.¹¹ Hypercapnia due to neuromuscular involvement, thrombotic events despite anticoagulation, and cardiac involvement might be contributing factors in the deteriorating respiratory condition leading to ICU admission and death.^12-14 It has been observed that there is usually rapid deterioration of the general condition within the first 24 hours of intubation and mechanical ventilation in patients with COVID-19 infection, having a direct correlation with poor outcomes.^15,16 This observation might encourage intensivists to adopt a higher threshold for intubating patients with COVID-19 infection. It is prudent to consider ICU admission and intubation/mechanical ventilation in this patient population as going into the danger zone rather than a bridge to recovery. Therefore, any intervention that prevents ICU admission, may have a high impact on mortality rates.

The length of hospital stay in the treatment arm was 7.6±3.5 days and in the standard group was 8.1±5.5 days. The big margin between the minimum and maximum days of hospitalization in both groups could not provide a significant P-value.

The data analysis of this clinical trial also showed that cardinal respiratory symptoms (cough, lassitude, and dyspnea) in patients with COVID-19 disease who received bromhexine treatment was remarkably less than the standard group. These findings may reflect the lower intensity of pulmonary involvement in the group of patients who received bromhexine.

SARS-CoV-2 activates several inflammatory and cytokine cascades in the human body. The CRP is a marker of inflammation which is suggested to be used in the screening of the patients suspected of COVID-19 disease. CRP is an acute-phase reactant that is synthesized by the liver under the trigger of IL-6. The plasma half-life of CRP is 19 hours.¹⁷ Higher CRP has been linked to unfavorable aspects of COVID-19 disease such as ARDS development.^18,19 In our clinical trial CRP was positive in 87.9% and 91.7% of patients in treatment and standard arms respectively, before the initiation of any treatment. Re-checking CRP two weeks after treatment showed complete improvement in CRP in 100% of patients in the bromhexine group while CRP remained positive in 83.3% of patients in the standard treatment arm. This is an interesting outcome in this clinical trial which indicates the effective impact of bromhexine in controlling inflammation.

Another lab finding that predicts the severity of illness is the NLR. It has been shown that the NLR of >3.3 is predictive of admission to ICU.²⁰ In our study, the NLR was higher than 3.5 in both groups before the treatment. In the bromhexine treated arm, by the end of the treatment, NLR was lower compared to the standard group but surprisingly, it was not statistically significant (P =0.052). Larger scale trials might be able to reveal the significant reduction of NLR with bromhexine.

LDH is an intracellular enzyme and presents in all cells, including the lung. Patients with COVID-19 disease release high amounts of LDH into circulation due to cytokine release and lung damage. The LDH level increases in patients with COVID-19 infection and returns to normal with the improvement of the disease. The LDH is a predictor of severity and mortality in hospitalized patients.²¹ In our study, the LDH levels in both groups were high on admission, but the LDH level was found to be lower in the patients in the bromhexine arm as compared to the standard group at the end of the therapy, however it was not statistically significant (P =0.056). The low levels of LDH in the bromhexine group are indicative of the less cell damage and therefore, better outcomes during COVID-19 pneumonia.

Conclusion

This study revealed the efficacy of early oral administration of bromhexine hydrochloride in the reduction of mortality of patients with COVID-19 disease. Patients treated with bromhexine may experience a milder course of the disease, and thus, the need for ICU transfer, intubation, and mechanical ventilation can be obviated. Along the same line, decreasing CRP after initiation of bromhexine is in favor of the efficacy of this medication in controlling inflammation and mitigating the disease. Bromhexine is a very inexpensive, affordable, safe, and over-the-counter medication in most countries that can easily be administered in remote and underserved areas. Despite the relatively small sample size and a single-center experience, our results are very encouraging, highlighting a potential breakthrough point in the management of patients with COVID-19 disease if confirmed after verification in large-scale clinical trials. Considering the current state of the pandemic, it may be a game-changer and can have a huge positive impact on resolving public health issues as well as on the world economy.

Acknowledgments

The authors would like to thank Dr. Sepideh Zununi Vahed for submitting the trial to IRCT. Dr. Majid Sadigh and Dr. Ramin Ahmadi for reviewing, Dr. Audrey Tolouian for her contribution in editing the final version of the manuscript.

Funding sources

This study was supported by Tabriz University of Medical Sciences, Tabriz, Iran.

Ethical statement

The study was approved by the Ethics Committee of the Tabriz University of Medical Sciences, Tabriz, Iran (IR.TBZMED.REC.1399.013).

Competing interests

The authors declare no conflict of interest in publishing this paper. This study not supported by any grant money from a pharmaceutical company or for-profit organization.

Authors’ contribution

KA, MRA and SS designed the study. KA, RT, MRA, AT, ST and SS contributed to the protocol development. KA, MRA, AT, MV, ST, TV, HV and PS collected the data. Data analysis and interpretation were conducted by KA, MRA and SS. The initial manuscript was drafted by KA, MRA, RT, SS and KRC. All authors critically revised the manuscript for important intellectual content and approved it for submission.

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