Etoposide treatment adjunctive to immunosuppressants for critically ill COVID-19 patients

Dear Editor,

In a recent article in the Journal, Cantini and colleagues¹ present favorable outcomes in a small cohort of moderate COVID-19 pneumonia patients treated with lopinavir-ritonavir in addition to baricitinib, a Janus kinase inhibitor (anti-JAK). Baricitinib is a cytokine release inhibitor and is active against SARS-CoV-2 endocytosis.

Current evidence suggests that systemic hyperinflammation and immune dysregulation play a key role in the development of severe lung and multiorgan damage found in critically ill COVID-19 patients.^{2 , 3 , 4} This massive cytokine release closely resembles that of macrophage activation syndrome or secondary hemophagocytic lymphohistiocytosis, hematological conditions in which acute respiratory distress syndrome (ARDS) is also common.^{2 , 5} Changes in lymphocyte sub-populations, cytokines dysregulation, presence of highly cytotoxic CD8+ T cells, and the accumulation of pro-inflammatory monocytes/macrophages in the lungs, seem to participate in the immune-mediated tissue damage.^{3 , 4 , 6}

Etoposide is a WHO Essential Medicine and powerful selective suppressor of activated T-cells and monocytes that reduces the production of inflammatory cytokines. Given its effectiveness against hyperinflammation,^{5 , 7} essentially by targeting monocytes and activated T cells and by moderating the cytokine storm, we propose a rationale for its use in critically ill COVID-19 patients. In this report we review the clinical course and outcome of 11 severe COVID-19 patients treated with etoposide as salvage therapy following prior immunosuppressants.

Patients eligible for etoposide treatment were older than 18 years, presented biochemical alterations suggestive of severe hyperinflammation (ferritin levels >1000 ng/ml and/or IL-6 values >50 pg/ml), ARDS (defined by PaO₂/FiO₂ < 300) and were not under mechanical ventilation. Prior treatment consisted on combinations of oxygen support, lopinavir-ritonavir, antimicrobials, methylprednisolone, and interleukin inhibitors. Patients not responding to a 3-day course of methylprednisolone plus Tocilizumab (IL-6 inhibitor) or Anakinra (IL-1 inhibitor) were offered etoposide. Orotracheal intubation, mechanical ventilation and prone positioning were applied when necessary according to the course of respiratory function. Prophylactic enoxaparin (40 mg per day) gas given regularly, and therapeutic anticoagulation was prescribed if thrombotic complications appeared. The study was conducted at the University Hospital of Burgos, Spain, and approved by the Local Institutional Ethics Committee (CEIm reference number, 2307) for off-label use of the drug. Informed consent from every participant (or relative) was obtained.

Thirteen patients received etoposide (50–150 mg/m²) out of 709 COVID-19 patients admitted to our center during the study period (March 2 to April 10, 2020). Overall, 412/709 developed ARDS (58.1%), of which 169 received methylprednisolone plus Tocilizumab (23.8%). Two out of 13 patients receiving etoposide were excluded because they were already intubated. A total of 11 patients (1.8%), 9 males and 2 females, with a median age of 58 (range, 41 to 79) were included. Clinical characteristics are shown in Table 1 . Median PaO₂/FiO₂ at admission was 98 (range, 52 to 174). Following etoposide treatment, the PaO₂/FiO₂ ratio improved an average of 195% (Fig. 1 ). Three patients needed mechanical ventilation. Nine patients fully recovered and were finally discharged home. Two patients died as a consequence of thrombotic complications. Patient #4 markedly improved her respiratory function allowing extubation but developed massive cerebral ischemic stroke (cardiac ultrasound detected a large thrombus in the right atrium), 2 days after ventilation withdrawal, and died 16 days after admission. Patient #5 recovered from severe ARDS with profound leukopenia, was discharged from the ICU, and died suddenly at day 24, presumably due to massive pulmonary thromboembolism, although autopsy was not performed. Apart from hematological toxicity and infection in patient #5, no other adverse effects attributable to etoposide were observed and the tolerance was good.

Table 1.

 

	Patient1	Patient2	Patient3	Patient4	Patient5	Patient6	Patient7	Patient8	Patient9	Patient10	Patient11	Patient12	Patient13
Characteristic
Age	56	41	63	79	60	70	55	57	64	58	79	73	42
Sex	male	male	male	male	female	male	male	female	male	male	male	male	male
Hypertension/obesity	No	No	No	Yes	Yes	No	No	Yes	No	Yes	Yes	Yes	Yes
pO2/FIO2 ratio	150	94	150	73	98	96	112	63	52	174	63	118	154
pCO2 (mmHg)	29	32	44	36	36	39	38	46	45	48	28	34	33
Ferritin (ng/mL)(**)	2020	1492	4014	4543	1316	1835	3232	3054	3359	2029	1697	3770	2665
CRP (ng/mL)	345	181	94	204	93	185	243	89	123	103	244	126	93
D-dimers (μg/mL)	3,4	5,5	1,8	7,8	16,5	1,1	1,2	1,9	2,3	0,3	2,8	10,3	0,6
Lymphocytes abs (x10^3/μL) (***)	0,3	0,4	0,4	0,1	0,3	0,6	0,6	1,8	0,5	0,5	0,2	0,4	0,1
Dose of etoposide (mg/m2)*	80	80	100	50	100	100	150	150	150	150	50	50	174
Total number of doses	1	1	2	1	2	1	2	2	2	2	2	1	1
Post etoposide pO2/FIO2	430	452	435	–	200	445	287	120	160	321	180	120	340
Etoposide administrated in ICU	YES	YES	NO	YES	YES	NO	NO	YES	YES	NO	YES	NO	NO
Mechanical ventilation	noninvasive	noninvasive	noninvasive	invasive	invasive	noninvasive	spontaneous	noninvasive	invasive	spontaneous	invasive	noninvasive	spontaneous
Outcome	Discharged	Discharged	Discharged	DNR	Death	Discharged	Discharged	Discharged	Discharged	Discharged	Hospitalized	Death	Discharged
Hospital stay (days)	15	15	13	11	13	14	7	20	5	5	15	14	32
Cytopenia >2 lines	NO	NO	NO	NO	YES	NO	NO	NO	YES	NO	NO	YES	NO
Infections	NO	NO	NO	NO	Enterococcus	NO	NO	NO	HSV-1	NO	NO	NO	NO

Fig. 1.

 

Noticeably, in our experience, only 1–2 doses of etoposide were enough to observe clinical improvement among severely ill COVID-19 patients, in terms of inflammatory serum markers (ferritin, CRP, D-dimer), vasopressor therapy requirement and respiratory support. In fact, only 3 patients ultimately required intubation, yet 2 of which died. These preliminary results on 11 patients confirmed the safety and efficacy of etoposide as adjunctive salvage treatment for critically ill COVID-19 ARDS patients, exhibiting systemic hyperinflammation and previously treated with corticosteroids and interleukin inhibitors.

A growing evidence suggests that COVID-19 disease is a biphasic disease.^{3 , 4 , 8} The initial stage, at which pre-symptomatic or pauci-symptomatic patients exhibit a preliminary and reversible state of immune-suppression associated to the viral load, ideally benefits from antivirals. Later on, patients may develop more severe leucopenia (mainly lymphopenia) along with increased inflammatory markers (CRP, ferritin, IL-6) that may end in a systemic hyperinflammatory state with accompanying cytokine discharge, accumulation of activated cells responsible for the lung damage, need for mechanical ventilation, thrombotic complications, and eventual death.^{2 , 3 , 4 , 8}

Although corticosteroid therapy in COVID-19 remains controversial, recent studies suggest a clinical benefit for severely ill COVID-19 ARDS patients in terms of mortality rate, need for mechanical ventilation, and hospital stay.^{9 , 10} Regarding oxygenation parameters, we observed that many severe COVID-19 patients presented with alarming PaO₂/FiO₂ ratios (commonly under 150, see Table-1) that, according to Berlin ARDS criteria, were immediate candidates for orotracheal intubation and mechanical ventilation. However, many of them exhibited a relatively preserved pulmonary function (mild dyspnea with or without tachypnea), showed preserved oxygen extraction and adequate organ perfusion without lactic acidosis, and ultimately avoided intubation. We hypothesize that SARS-CoV-2 related ARDS distinct pathophysiologic features permit management of many critically ill patients with non-invasive ventilatory support, waiting for the anti-inflammatory reversal effect of etoposide plus adjunctive immunomodulators.

The lack of comparison group and the low number of participants are obvious limitations of this study. Due to the severity of patients included in the study, with remarkable hyperinflammation data, all patients had received methylprednisolone and Tocilizumab or Anakinra prior to etoposide, so both drugs can be potential confounders in the interpretation of the results. However, etoposide was administered whenever patients did not respond to prior anti-inflammatory treatment, and at the stage of progressive organ dysfunction.

In this preliminary experience, salvage treatment with etoposide in adjunction to immunosuppressants resulted in overall favorable outcome of a small cohort of severely ill COVID-19 ARDS patients presenting with systemic hyperinflammation. The currently ongoing clinical trial NCT04356690, started on May 8, 2020, will likely contribute to evaluate the safety and efficacy of etoposide in COVID-19 patients.