Darunavir/Cobicistat Is Associated with Negative Outcomes in HIV-Negative Patients with Severe COVID-19 Pneumonia

Abstract

The aim of this study was to evaluate both positive outcomes, including reduction of respiratory support aid and duration of hospital stay, and negative ones, including mortality and a composite of invasive mechanical ventilation or death, in patients with coronavirus disease 2019 (COVID-19) pneumonia treated with or without oral darunavir/cobicistat (DRV/c, 800/150 mg/day) used in different treatment durations. The secondary objective was to evaluate the percentage of patients treated with DRV/c who were exposed to potentially severe drug–drug interactions (DDIs) and died during hospitalization. This observational retrospective study was conducted in consecutive patients with COVID-19 pneumonia admitted to a tertiary care hospital in Modena, Italy. Kaplan–Meier survival curves and Cox proportional hazards regression were used to compare patients receiving standard of care with or without DRV/c. Adjustment for key confounders was applied. Two hundred seventy-three patients (115 on DRV/c) were included, 75.8% males, mean age was 64.6 (±13.2) years. Clinical improvement was similar between the groups, depicted by respiratory aid switch (p > .05). The same was observed for duration of hospital stay [13.2 (±8.9) for DRV/c vs. 13.4 (±7.2) days for no-DRV/c, p = .9]. Patients on DRV/c had higher rates of mortality (25.2% vs. 10.1%, p < .0001. The rate of composite outcome of mechanical ventilation and death was higher in the DRV/c group (37.4% vs. 25.3%, p = .03). Multiple serious DDI associated with DRV/c were observed in the 19 patients who died. DRV/c should not be recommended as a treatment option for COVID-19 pneumonia outside clinical trials.

Background

A few antiviral agents for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been studied, among others, remdesivir, lopinavir, and darunavir (DRV).^1,2 Clinical trials with Ebola and influenza promoted remdesivir as a promising and potent drug against SARS-CoV-2.³ Results from randomized clinical trials (RCTs) are still inconclusive, while discouraging data were obtained in a Chinese RCT [hazard ratio (HR) = 1.23; (95% confidence interval, CI = 0.87–1.75)],⁴ a phase 3 RCT showed that remdesivir was superior to placebo in shortening the time to recovery (11 vs. 15 days).⁵ In consideration of these results, remdesivir is now approved for the treatment of coronavirus disease 2019 (COVID-19) in at least 50 countries.

In consideration of the gained clinical experience with lopinavir/ritonavir as a treatment option for SARS and MERS outbreaks in 2012, this compound was also suggested for SARS-CoV-2 infection.⁶ Lopinavir/ritonavir is a HIV protease inhibitor and it has been widely used in HIV setting in the previous decade.⁷ In an RCT conducted in China, there was no difference in mortality and time to clinical improvement in patients treated with lopinavir/ritonavir over standard of care (HR = 1.24; 95% CI = 0.90–1.72).⁸ The RECOVERY RCT, including 5,040 patients showed that lopinavir/ritonavir was not associated with reductions in 28-day mortality, duration of hospital stay, or risk of progressing to invasive mechanical ventilation (IMV) or death.⁹ Moreover, it has been shown that ritonavir is associated with clinically significant drug–drug interactions (DDIs) with hydroxychloroquine, an agent previously used in patients with COVID-19 pneumonia admitted to hospital.¹⁰ This interaction may result in prolonged QT interval leading to malignant arrhythmias.¹⁰

DRV is another HIV protease inhibitor with similar mechanism of action as lopinavir.¹¹ Cobicistat (c) is used as a booster to increase plasma half-life of DRV and, similarly to ritonavir, has a high potential to cause DDI notably due to its strong inhibitory effect on CYP3A4 or drug transporters resulting in increased exposure of substrate drugs and related risk of adverse drug effects.¹²

The use of DRV/c was also initiated in rapid response to the COVID-19 public health emergency, at which time there was no information about efficacy for the treatment of COVID-19.

The rationale for the use of DRV/c over lopinavir/ritonavir was argued by more favorable metabolic profile and less DDI, as shown in the HIV setting.^13,14 However, an in vitro study showed that DRV had no antiviral activity against SARS-CoV-2, as the binding site of DRV little interact with SARS-CoV-2 main protease active site.¹⁵ In addition, a recently published RCT reported that administration of DRV/c for 5 days did not fasten a viral clearance over a standard of care alone in a small sample of 30 patients.¹⁶

The aim of this study was to evaluate both positive outcomes, including reduction of respiratory support aid and duration of hospital stay, and negative ones, including mortality and a composite of IMV or death, in patients with COVID-19 pneumonia treated with or without oral darunavir/cobicistat (DRV/c, 800/150 mg/day) used in different treatment durations. Secondary objective was to evaluate the percentage of patients treated with DRV/c who were exposed to potentially severe DDIs and died during hospitalization.

Methods

Data collection and study design

An exploratory retrospective analysis was conducted in consecutive HIV-negative patients with COVID-19 pneumonia admitted at Policlinico Hospital, Modena, Italy between 21 February and April 9, 2020 (the date of enrollment of the last patient). SARS-CoV-2 infection was confirmed through reverse-transcriptase–polymerase chain reaction assays performed on nasopharyngeal swab specimens. Data were obtained from electronic health records and complied fully with the Italian law on personal data protection and the Ethics Committee of the Area Vasta Nord Emilia Romagna who approved the study (396/2020/OSS/AOUMO—Cov-2 MO-Study).

Standard of care

All patients were treated in agreement with the Regional COVID-19 Guidelines of Emilia Romagna about the treatment of COVID-19.¹⁷ Patients received oxygen supply to target SaO₂ >90% through nasal canula or Venturi mask, or with noninvasive ventilation (NIV) or IMV.

During the period of the study, associated treatments consisted of:

Hydroxychloroquine (400 mg BID on day 1 followed by 200 mg BID on days 2 to 5 eventually adjusted for creatinine clearance estimated by a CKD algorithm);

Azithromycin (500 mg QD for 5 days) at physician's discretion when suspecting a bacterial respiratory superinfection;

Low-molecular-weight heparin for prophylaxis of deep vein thrombosis according to body weight and renal function;

DRV/c (800/150 mg QD) for 14 days were used up to 18 March, when a clinical trial on the former did not show any benefit of protease inhibitors against the standard of care.⁸

When DRV/c was initiated, there was no information about duration of treatment. For this reason, we first decided to treat the patients for 14 days similarly to the Chinese study on lopinavir/ritonavir.⁸ Subsequently, we reduced duration of DRV/c treatment to 5 days only when DRV/c RCT protocol became available on ClinicalTrials.org website.¹⁸

In the same observational period, three patients only were treated with LPV/r and were excluded from the analyses.

When results on lopinavir became available, we decided to suspend the use of DRV. The observational study continued enrolling consecutive patients (not treated with DRV/c) up to April 9, 2020, when data were censored.

Moreover, some patients were also treated with immune-active agents, such as tocilizumab and glucocorticoids. Criteria for use of tocilizumab in our center has been described elsewhere.¹⁹ It must be noticed that tocilizumab hospital supply was scarce at the beginning of the epidemic due to the high national request, which created an intermittent shortage while it increased progressively during the observation period. Glucocorticoids were administered alone when tocilizumab was not available or rather, if PaO₂/FiO₂ did not improve after 3 days of tocilizumab infusion. At the time, the results of RECOVERY trial²⁰ had not been available yet and treatment comprised 1 mg/kg/day of methylprednisolone for 5 days, subsequently tapered after 2 days of improvement of acute respiratory distress syndrome (ARDS) either in oxygen therapy (OT) or invasive or non-IMV.

Covariates

The patients' full medical history, demographic and epidemiological data, as well as the value of PaO₂/FiO₂ at baseline were obtained at the hospital admission. The risk of multiorgan failure and mortality was assessed with standardized Subsequent Organ Failure Assessment (SOFA) score.²¹ Other covariates, including age and sex, were considered. Clinical data with patients' signs, symptoms, blood count, coagulation, and inflammatory and biochemical markers were routinely collected and reported in an electronic patient chart. Other pharmacological interventions included as covariates were: use of tocilizumab, glucocorticoids and low-molecular-weight heparin.

Outcome measures

The study comprised two sets of outcome measures, respectively, clinically meaningful positive and negative outcomes. Positive outcomes included clinical improvement and time to discharge. Clinical improvement was defined as the time from admission to an improvement of two points on a six-category ordinal scale or live discharge from the hospital, whichever came first. Following an approach similar to what was suggested by WHO R&D Blueprint expert group,²² we defined six possible consecutive respiratory support states that are hereinafter reported and referred as intermediate states:

State 1: no respiratory support (NRS);

State 2: OT;

State 3: NIV;

State 4: IMV;

State 5: OT in recovery;

State 6: NRS in recovery.

Negative outcomes include mortality and a composite of IMV or death. Indication for mechanical ventilation were neurologic failure (i.e., altered consciousness with a Glasgow Coma Scale score <10), cardiovascular failure (i.e., vasopressor requirement or major electrocardiogram (ECG) changes, including arrhythmia or changes in repolarization phase) and respiratory failure defined by the presence of at least 2 of the following criteria: respiratory rate >30 bpm, respiratory distress with activation of accessory respiratory muscles, need for FiO₂ at 80% or more to maintain an SaO₂ level at 90%, or a PaO₂/FiO₂ <100 mmHg.^23,24

The risk of potentially severe DDI between DRV/c and other medications was assessed with INTERCheck²⁴ considering all drugs that the patients received at the day of death. The causal relationship with adverse events was not evaluated.

Statistical analyses

The patients' sociodemographic and clinical characteristics of patients were assessed using univariate analysis with Chi-squared test for categorical variables and t-test for continuous variables. Survival analysis was conducted to evaluate possible benefits of DRV/c during the hospitalization.

Survival for each outcome was first described using Kaplan–Meier survival curves comparing patients receiving DRV/c plus standard care with those treated only with standard of care. Difference between curves was evaluated using Log-Rank and Wilcoxon tests. Successively, differences in two groups were evaluated using HRs obtained by Cox proportional hazards regression in four models. The first was a raw model; the second was adjusted for age and sex; the third was also adjusted for SOFA score; and the fourth model was also adjusted for drugs with potential clinical improvement (corticosteroids, tocilizumab, or low-molecular-weight heparin). In the absence of preliminary data, it was impossible to predict if the sample size collected could ensure the appropriate statistical power for these analyses. Statistical significance (alpha) was 0.05 for all tests. Analyses were performed using JMP Pro 14.1.0 (SAS Institute, Inc., Cary. NC). The study was approved by the Regional Ethical Committee of Emilia Romagna (protocol number: AOU 0018046/20).

Results

A total of 273 patients with COVID-19 infection were admitted and 115 of them received DRV/c within the standard of care. The mean age was 64.6 (±13.2) years and 75.8% of admitted patients were males (Table 1). Sociodemographic characteristics did not differ between the two groups. Patients receiving DRV/c had higher baseline SOFA score [2.7 (±1.7) vs. 2.16 (±1.9), p = .01], but respiratory function at baseline assessed with PaO₂/FiO₂ ratio was similar between the two groups [256 (interquartile range, IQR: 146.5–286.75) vs. 253.5 (IQR: 138.75–268.75) mmHg] (Table 1).

Table 1.

Sociodemographic and Clinical Characteristics of Patients

	Total N = 273	No DRV/c N = 158	DRV/c N = 115	p
Age, years, mean (±SD)	64.6 (13.2)	65.2 (12.4)	63.8 (14.4)	.40
Females, n (%)	66 (24.2)	43 (27.2)	23 (20.0)	.17
Baseline SOFA score, mean (±SD)	2.41 (1.8)	2.16 (1.9)	2.7 (1.7)	.01
Baseline PaO₂/FiO₂, mmHg, median (IQR)	256 (141–290.5)	253.5 (138.75–268.75)	256 (146.5–286.75)	.94
Comorbidities, n (%)
Hypertension, n (%)	70 (57.4)	33 (62.3)	37 (53.6)	.34
Diabetes, n (%)	20 (16.4)	11 (20.8)	9 (13.0)	.25
CVD, n (%)	19 (15.6)	11 (20.8)	8 (11.6)	.17
Cancer, n (%)	8 (6.6)	6 (11.3)	2 (2.9)	.06
BMI, kg/m², mean, (±SD)	28.0 (4.4)	25.4 (1.4)	28.9 (4.7)	.06
Duration of COVID-19 symptoms, days, mean (±SD)	6.6 (4.2)	7.0 (4.4)	4.9 (3.2)	.03
Concomitant drugs, n (%)
Corticosteroids, n (%)	80 (29.30)	50 (31.7)	30 (26.1)	.32
Tocilizumab, n (%)	117 (42.86)	77 (48.7)	40 (34.8)	.02
Heparin, n (%)	148 (54 2)	82 (51.9)	66 (57.4)	0.37
Seven-category scale (maximum score)
3: Hospitalization, not requiring supplemental oxygen, n (%)	40 (14.65)	34 (21.5)	6 (5.2)	.002
4: Hospitalization, requiring supplemental oxygen, n (%)	137 (50.18)	74 (46.8)	63 (54.8)
5: Hospitalization, requiring non-IMV, n (%)	44 (16.12)	22 (13.9)	22 (19.1)
6: Hospitalization, requiring IMV, n (%)	52 (19.05)	28 (17.7)	24 (20.9)
Time from mechanical ventilation to supplemental oxygen, median (IQR)	8 (4–11)	8 (3–9)	10 (6–18)	.08
Time from NIV to discharge, median (IQR)	11 (9–12)	12 (10–13)	10 (7–12)	.30
Time from/to supplemental oxygen/no oxygen to discharge, median (IQR)	8 (5–12)	8 (5–12)	7 (3–13)	.63
Duration of OT pre-NIV, median (IQR)	5 (2–10.25)	5 (2–10)	5 (2–11)	.59
Duration of OT post-NIV, median (IQR)	9 (6.5–11.5)	9 (7.3–10.8)	10 (5.5–14)	.50
Duration of IMV, median (IQR)	5 (3–9.5)	5 (1.75–8.5)	6 (2–10)	.47
Hospital stay, (mean ± SD)	13.3 (7.9)	13.4 (7.2)	13.2 (8.9)	.9
Mortality, n (%)	45 (16.48)	16 (10.1)	29 (25.2)	<.0001
Discharge, n (%)	145 (53.11)	78 (49.4)	67 (58.3)	<.0001
Mechanical ventilation and/or mortality, n (%)	83 (30.40)	40 (25.32)	43 (37.39)	.03

BMI, body mass index; COVID-19, coronavirus disease 2019; CVD, cardiovascular diseases; DRV/c, darunavir/cobicistat; IQR, interquartile range; NIV, noninvasive ventilation; OT, oxygen therapy; SD, standard deviation; SOFA, Subsequent Organ Failure Assessment.

Duration of symptoms was shorter in the DRV/c group [4.9 (±3.2) vs. 7.0 (±4.4), p = .03], but the clinical presentation during hospital admission appeared to be more severe according to the six-category scale (p = .002, Table 1). The use of concomitant drugs was similar between the two groups, except for tocilizumab, which was higher in the group that did not receive DRV/c (48.7% vs. 34.8%, p = .02, Table 1).

Clinical improvement was similar between the groups as depicted by time from mechanical ventilation to supplemental oxygen, time from nonmechanical ventilation to discharge, time from/to supplemental oxygen/no oxygen to discharge (p = .08, p = .30, p = .63, respectively, Table 1). The same was observed for duration of hospital stay [13.2 (±8.9) for DRV/c vs. 13.4 (±7.2) days in non-DRV/c, p = .9, Table 1].

With regard to negative outcomes, patients undergoing treatment with DRV/c had higher rates of mortality (25.2% vs. 10.1%, p < .0001) and of the composite outcome of mechanical ventilation and death (37.4% vs. 25.3%, p = .03, Table 1).

Signs, symptoms, and biochemical parameters at the admission are shown in Table 2. Higher prevalence of dyspnea, cough, diarrhea, and headache was observed in patients who received DRV/c, whereas inflammatory biomarkers, such as C-reactive protein, ferritin, and interleukin 6 did not differ between the groups (Table 2).

Table 2.

Baseline Sign and Symptoms and Laboratory Parameters

	Total	No DRV/c	DRV/c	p
Fever, median (IQR)	36 (36–37)	38 (36–38)	37 (37–38)	.88
Dyspnea, n (%)	57 (20.88)	18 (11.4)	35 (30.4)	<.0001
Cough, n (%)	55 (20.14)	21 (13.3)	24 (29.6)	.0009
Myalgia, n (%)	5 (1.83)	1 (0.6)	4 (3.5)	.08
Sputum, n (%)	5 (1.83)	2 (1.3)	3 (2.6)	.41
Headache, n (%)	12 (4.40)	2 (1.3)	10 (8.7)	.003
Diarrhea, n (%)	12 (4.40)	2 (1.3)	10 (8.7)	.003
Systolic pressure, mmHg median (IQR)	120 (110–133)	130 (116–148)	130 (119–144)	.90
Biomarkers, median (IQR)
Hemoglobin, g/L	13.3 (12–14.2)	13.15 (12.1–14.28)	13.3 (11.9–14.2)	.72
White cells, mm³	6,010 (4,842.5–8,415)	6,250 (5,030–8,520)	5,800 (4,570–8,340)	.31
Lymphocytes, %	28.56 (14.35–35.84)	28.85 (15.65–35.84)	9.2 (2.09–37.32)	.31
Total lymphocytes, mm³	1,663.1 (975–2,507.74)	1,671.36 (982.5–2,503.63)	1,050 (830–2,526.72)	.57
Platelets, 10⁹/L	190 (147–252)	204 (160–268.5)	181 (136–232)	.22
Alanine aminotransferase, U/L	31 (21–47)	35 (22–51)	27 (20–40)	.002
Bilirubin, mg/dL	0.63 (0.49–0.82)	0.61 (0.50–0.80)	0.63 (0.45–0.85)	.95
Calcium, mg/dL	8.5 (8.2–8.9)	8.5 (8.2–9)	8.5 (8.2–8.8)	.50
Creatine kinase, U/L	138.5 (58.25–288.25)	111 (48.5–243.5)	166 (70–310)	.009
Chloride, mmol/L	99 (97–102)	99 (96–101.25)	99.5 (97–102)	.48
Creatinine, mg/dL	0.87 (0.7–1.1)	0.84 (0.69–1.08)	0.88 (0.71–1.17)	.39
D-dimer, ng/L	1,200 (755–2,132.5)	1,165 (755–2,175)	1,250 (735–2,115)	.64
Lactate dehydrogenase, U/L	624 (427–792)	624 (497.5–758)	624 (469–814)	.95
Potassium, mmol/L	3.7 (3.5–4)	3.8 (3.5–4.1)	3.6 (3.5–3.95)	.06
Sodium, mmol/L	137 (134–139)	137 (134–139)	137 (134.5–138.5)	.75
Ferritin, ng/L	815.5 (417–1,179.5)	861.5 (461.25–1,202.5)	411.5 (366–457)	.15
C-reactive protein, mg/dL	11.95 (4.7–17.58)	12.95 (5.58–18.08)	7.75 (4.25–17.03)	.24

Kaplan–Meier survival curves compared positive and negative outcomes in patients treated with or without DRV/c (Fig. 1). Clinical improvement was similar in both groups [median 11 in DRV/c vs. 12 days in non-DRV/c group; Wilcoxon test = 0.17; Log-Rank test = 0.14; HR = 1.25; 95% CI = 0.92–1.71; p = .15] (Fig. 1A). This result was confirmed in a model adjusted for age, sex, SOFA score, heparin, corticosteroids, and tocilizumab (HR = 1.17; 95% CI = 0.83–1.64; p = .38; Table 3, model 4).

FIG. 1.

Kaplan–Meier survival curves compared positive and negative outcomes in patients treated with or without darunavir/cobicistat. (A) describes clinical improvement, (B) time to discharge, (C) mortality, and (D) probability of invasive mechanical ventilation or mortality.

Table 3.

Association Between Darunavir/Cobicistat and Clinical Outcome

	HR (95% CI)
	Model 1	Model 2	Model 3	Model 4
Clinical improvement of 2 points or discharge	1.25 (0.92–1.71)	1.07 (0.78–1.46)	1.20 (0.87–1.69)	1.17 (0.83–1.64)
Clinical improvement of 2 points or discharge	p = .15	p = .69	p = .26	p = .38
Discharge	1.31 (0.95–1.82)	1.19 (0.86–1.66)	1.63 (1.13–2.35)	0.90 (0.61–1.34)
Discharge	p = .10	p = .29	p = .009	p = .62
Mortality	2.72 (1.47–5.01)	2.31 (1.24–4.32)	1.87 (0.99–3.54)	1.72 (0.92–3.25)
Mortality	p = .0014	p = .0083	p = .05	p = .09
IMV or mortality	1.56 (1.02–2.40)	1.45 (0.94–2.24)	1.25 (0.80–1.94)	1.24 (0.79–1.93)
IMV or mortality	p = .04	p = .09	p = .33	p = .36

Model 1 is a raw model; Model 2 is adjusted for age and sex; Model 3 is adjusted for age, sex, and SOFA score; Model 4 is adjusted for age, sex, SOFA score, corticosteroids, tocilizumab, and heparin.

CI, confidence interval; HR, hazard ratio.

Time to discharge was similar between two groups (median 14 in DRV/c vs. 16 days in non-DRV/c group; group (Wilcoxon test = 0.15; Log-Rank test = 0.09; HR = 1.31; 95% CI = 0.95–1.82; p = .10) (Fig. 1B). In multivariate model, use of darunavir was not associated with higher probability of discharge (HR = 0.90; 95% CI = 0.61–1.34) p = .62; Table 3, model 4).

Mortality was higher in patients receiving DRV/c than in the control group (Wilcoxon test = 0.0008; Log-Rank test = 0.002; HR = 2.72; 95% CI = 1.47–5.01; p = .0014) (Fig. 1C). However, this relationship was not confirmed in multivariable model (HR = 1.72; 95% CI = 0.92–3.25; p = .09).

Probability of IMV or mortality was not different between the groups, as depicted in Figure 1D (Wilcoxon test = 0.26; Log-Rank test = 0.76; HR 1.56; 95% CI = 1.02–2.40; p = .04) (Fig. 1D). Furthermore, this association was not found in multivariable model after correction for identified confounders [HR = 1.24; (95% CI = 0.79–1.93); p = .36; Table 3, model 4].

Among the 115 patients treated with DRV/c, 52 (45.2%) received less than 5-day course of treatment, whereas 63 (54.8%) received the drug for more than 5 days. Patients receiving less than a 5-day course of DRV/c had the highest risk of mortality (HR = 3.21; 95% CI = 1.50–6.86; p = .003) and of composite outcome of mortality and IMV (HR = 2.52; 95% CI = 1.48–4.30 = p = .0007, model 4, Table 4) when compared with patients not receiving DRV/c. SOFA score for patients receiving DRV/c for less than 5 days and more than 5 days was similar (mean ± standard deviation: 2.7 ± 2.2 and 2.7 ± 1.7, p = .95)

Table 4.

Association Between Duration of Treatment with Darunavir/Cobicistat and Clinical Outcomes

	HR (95% CI)^a
	Model 1	Model 2	Model 3	Model 4
<5 days
Clinical improvement of 2 points or discharge	1.66 (1.12–2.45)	1.21 (0.81–1.81)	1.42 (0.92–2.18)	1.43 (0.93–2.22)
Clinical improvement of 2 points or discharge	p = .01	p = .36	p = .11	p = .11
Discharge	1.40 (0.92–2.16)	1.04 (0.68–1.61)	1.28 (0.81–2.02)	1.30 (0.80–2.11)
Discharge	p = .11	p = .84	p = .29	p = .28
Mortality	3.41 (1.68–6.93)	4.48 (2.17–9.27)	3.54 (1.61–7.80)	3.21 (1.50–6.86)
Mortality	p = .0007	p < .001	p = .002	p = .003
Composite of IMV and mortality	2.76 (1.67–4.55)	3.08 (1.85–5.11)	2.48 (1.46–4.21)	2.52 (1.48–4.30)
Composite of IMV and mortality	p < .0001	p < .0001	p = .0008	p = .0007
≥5 days
Clinical improvement of 2 points or discharge	1.02 (0.69–1.49)	0.97 (0.66–1.43)	1.02 (0.69–1.52)	0.95 (0.63–1.43)
Clinical improvement of 2 points or discharge	p = .92	p = .88	p = .92	0.80
Discharge	1.27 (0.86–1.88)	1.35 (0.91–2.01)	1.51 (1.00–2.27)	120 (0.78–1.85)
Discharge	p = .24	p = .14	p = .05	p = .41
Mortality	2.18 (1.06–1.48)	1.40 (0.65–2.99)	1.16 (0.54–2.49)	1.05 (0.46—2.29)
Mortality	p = .03	p = .39	p = .71	p = .89
IMV and mortality	0.92 (0.52–1.62)	0.76 (0.43–1.36)	0.66 (0.37–1.20)	0.67 (0.37–1.20)
IMV and mortality	p = .76	p = .36	p = .17	p = .18

Model 1 is a raw model; Model 2 is adjusted for age and sex; Model 3 is adjusted for age, sex, and SOFA score; Model 4 is adjusted for age, sex, SOFA score, corticosteroids, tocilizumab, and heparin.

The reference group is represented by patients not receiving DRV/c.

Among patients treated with DRV/c, 19 died during treatment course and among them 11 (57.9%) were at risk for potentially severe DDIs (Table 5): 1 patient had 3 potentially severe DDIs, 4 patients had 2 potentially severe DDIs, and 6 patients 1 potentially severe DDIs. Trazodone, clarithromycin, diazepam, and clonazepam were administered during the hospital stay, but no dose adjustment was made. Potential adverse events associated with DDI were not mentioned as cause of death in none of these cases.

Table 5.

Potentially Severe Drug–Drug Interactions Among 19 Patients Who Died During Darunavir/Cobicistat Administration

Concomitant drug	Potential adverse events	Patients, n (%)
Atorvastatin	Atorvastatin toxicity (myopathy, rhabdomyolysis)	8 (42.1)
Amlodipine	Amlodipine toxicity (hypotension, rebound tachycardia)	3 (15.8)
Trazodone	Trazodone toxicity (sedation, hypotension, syncope)	2 (10.6)
Lercanidipine	Lercanidipine toxicity (hypotension, rebound tachycardia)	1 (5.3)
Clarithromycin	Darunavir toxicity (cardiac) and clarithromycin toxicity (QTc prolongation)	1 (5.3)
Diazepam	Benzodiazepine toxicity (sedation, respiratory depression)	1 (5.3)
Clonazepam	Benzodiazepine toxicity (sedation, respiratory depression)	1 (5.3)

Discussion

We provided comprehensive measures of positive and negative outcomes in patients with COVID-19 pneumonia receiving treatment with or without DRV/c. We were also able to describe potential DDI that provides a useful insight on safety profile of this compound in COVID-19 patients.

Results of this observational retrospective study suggest that DRV/c was not associated with clinical improvement or shorter hospital stay in seriously ill patients with COVID-19. We also found that DRV/c was significantly associated with an increased risk of mortality and/or mechanical ventilation, suggesting a word of caution in its use outside research setting.

Lack of DRV/c efficacy was also shown in a recently published RCT, which used vial clearance depicted with negative PCR in oropharyngeal swab, as major study end point.¹⁶ This interesting study apparently did not analyze severe patients given that one single case progressed to ARDS. Therefore, it was not possible neither to describe in detail switching of respiratory states nor to assess the impact of DRV/c on mortality and on risk of IMV. On the other side, the recently published RECOVERY trial showed that lopinavir/ritonavir, a drug from the same class as DRV/c, was not associated with reduced risk of IMV or death (risk ratio = 1.09; 95% CI = 0.99–1.20; p = .092).⁹

The observational nature of our study cannot rule out all potential confounders associated with study outcomes. We argue that high prevalence of dyspnea, although with no difference in PaO₂/FiO₂, and higher SOFA score at admission may have driven the clinician to add DRV/c on the top of the standard of care. Conversely, the higher proportion of treatment with tocilizumab in patients not receiving DRV/c may be explained by greater availability of this agent in the later stage of the observational period, while DRV/c used was discontinued. Nevertheless, adjustment for SOFA and tocilizumab were included in the multivariable models.

With regard to negative outcomes, crude analyses depicted a higher mortality associated with DRV/c, also described in a large multicenter observational study, including over 450 patients [Iacoviello L, article submitted].

This study provided two novel insights, possibly interacting. The first refers to the impact of DRV/c duration of treatment on clinical outcomes. Apparently, exposure to DRV/c less than 5 days was associated with higher mortality even after adjustment for associated treatment. Moreover, longer duration was not associated with positive outcomes, suggesting that antiviral agents may be useless in the inflammatory stage of the disease. The second refers to recognition of multiple DDI in people who underwent short duration of DRV/c and died. As mentioned, DDI were not reported as a cause of death among the 19 patients who died. Nevertheless, this causality is not easy to be recognized without autopsy. We, therefore, can neither confirm nor exclude a causal relation between DDI and death. However, DDI risk may still be considered a major concern of the use of this drug in COVID-19.²⁵

The identified top 7 potentially severe DDI referred to statin, antihypertensive drugs, psychoactive agents, and antibiotics with potential impact on QT elongation. Patients with high cardiovascular risk were at higher risk for COVID-19,¹⁰ therefore patients admitted to hospital continued primary or secondary cardiovascular risk prevention with statin during the hospital stay. Moreover, some cardiologists support the use of statins as an adjunctive treatment in patients with COVID-19 due to their immunomodulatory properties, and the experience accumulated in the management of various infectious diseases, such as community-acquired pneumonia and influenza.²⁶ DRV/c may enhance myopathy and rhabdomyolysis associated with atorvastatin. Moreover, creatine kinase elevation is common during COVID-19 making it difficult to discriminate drug toxicity.²⁷

High cardiovascular risk is also associated with hypertension, and use of amlodipine and lecardipine is often necessary in the armamentarium of this condition in hospitalized patients. Calcium blocker in association with DRV/c may induce rapid onset of hypotension and tachycardia, often misinterpreted with cardiovascular adaptation to hypoxia. CNS agents are necessary in the management of seriously ill patients, but concomitant use of DRV/c may increase the risk of respiratory depression, which is particularly harmful in hypoxic patients. Some anti-infective agents, including clarithromycin, and to a less extent chloroquine, largely used in these patients, may increase QT interval, which is increased in coadministration with DRV/c, possibly leading to malignant arrhythmia and potentially sudden death.

Previous articles have notified a clinically significant DDI among hydroxychloroquine, azithromycin, and ritonavir in patients with COVID-19 pneumonia that led to prolonged QT interval.^10,28 Drug Interactions Checker reports reveal a potential weak interaction between hydroxychloroquine and DRV/c and no interaction with azithromycin, but coadministration has not been studied and it is not known if the interaction is clinically relevant. DRV/c could potentially increase hydroxychloroquine exposure by inhibition of P450 enzymes, but dose adjustment is not recommended.²⁹ However, we cannot exclude a potential interaction between the two that led to unfavorable results.

Several potentially severe DDIs found in our study could be easily managed with an appropriate drug monitoring (e.g., dose adjustment), but our findings suggest that these interactions might have not been promptly recognized. DDI should be assessed on a daily base in hospitalized patients. Careful monitoring of clinical parameter or deprescribing the interacting drugs (e.g., statin withdrawal during DRV/c coadministration) and the use of Drug Interactions Checker possibly integrated in electronic prescription software.

As previously stated, this observational study has several limitations intrinsic in the observational nature of the study, in which it is not possible to adjust for all confounders. In particular, assessment of DDI with concomitant medications was evaluated only in patients who received DRV/c and died. Nevertheless, the 45 deaths observed in the study period were never attributed to potential cases of DDI and the risk of mortality associated to potentially severe DDI has not be evaluated in this study.

Information about side effects were not collected, thus limiting the possibility to evaluate the causal relationship with the drug toxicity or the potentially severe DDI.

Although inflammation has been shown to increase the concentration of DRV/c,³⁰ the association between CRP or ferritin and the rate of mortality within the DRV/c group could not be evaluated as the data on these parameters were available in few patients.

Another limitation is that, due to the observational nature of the study, the groups of patients receiving DRV/c was unbalanced over time. Most of them were enrolled in the very beginning of the pandemic (February–March 2020 only) and therefore, we cannot exclude that mortality rate decreased with experience of the medical center over time.

Some points of strength should be noticed. Study outcomes included both positive and negative ones. Furthermore, this study evaluated the role of DRV/c assessing the same outcome measures used in recent RCTs on lopinavir/ritonavir⁸ and remdesivir.^4,5

This study reports a relatively large sample size and moreover provides a description of DDIs with other comedication frequently used in COVID-19 patients, even though the risk of potentially severe DDIs has been evaluated only in patients who died, therefore, the relation between mortality and DDIs cannot be established.

Our study contributes to the better understanding of DRV/c use in real-life experience, providing original data regarding safety issues, increasingly described in association with this treatment. Nevertheless, it should be acknowledged that it is hard to assess adverse events in an acute disease such as COVID-19. In fact, some of the adverse events described in HIV setting require long-term exposure, unlikely to occur in COVID-19 due to short duration of DRV/c treatment.

Conclusion

This observational retrospective study describes DRV/c use in real life suggesting lack of benefit in patients with COVID-19. An increased risk of negative outcome was found in short-term treatment. We described that DRV/c potentially has severe DDI with concomitant medications that may contribute to death. Serious DDI occurred in association with this compound in hospitalized patients that should be addressed in ongoing RCTs. According to these data, DRV/c should not be recommended as a treatment option for COVID-19 pneumonia outside clinical trial.

Footnotes

Acknowledgments

The authors would like to thank Fogliani Rossella, Righini Grazia, and Lugli Mario for their contribution in the data collection. The authors would like to thank the Modena COVID-19 Working Group.

Author Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

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