The first component of this study investigated the in vitro safety and virucidal activity of clinically utilized dilutions of J&J/S9. Due to the urgency to limit SARS-CoV-2 nasal infections during the ongoing pandemic, a clinical trial of the safety and efficacy of J&J/S high-volume rinses in subjects with nasal SARS-CoV-2 cavity infections was then performed in parallel with the pharmacokinetic (PK) and virucidal pharmacodynamic (PD) studies of J&J/S in SARS-CoV-2-infected cultured human nasal epithelia (HNE).
Safety studies revealed that exposure of HNE cultures to serial dilutions of J&J/S induced transient decreases in barrier function (transepithelial resistance) at concentrations above 1/2 tsp J&J/240 ml saline without changes in cell composition (Fig. S1A, B). Assays of virucidal activity demonstrated that non-toxic concentrations of J&J/S (½ tsp J&J/240 ml saline) were virucidal in vitro against NL63 coronavirus and respiratory syncytial virus (Fig. S1C, D). Notably, rapid and robust SARS-CoV-2 virucidal activity was observed when SARS-CoV-2 virus at varying titers was exposed to this concentration of J&J/S (Fig. 1A).
Having demonstrated in vitro safety and virucidal activity, an outpatient clinical trial of J&J/HTS nasal irrigation was performed in subjects with nasal swab qPCR-documented SARS-CoV-2 infection. Seventy-two subjects were randomized into three groups: 1) twice daily nasal irrigation with 1/2 tsp J&J Baby Shampoo in 240 ml HTS; 2) twice daily irrigation with HTS alone; or 3) no intervention (see Table 1, Fig. S1E). The primary study endpoint was qPCR-measured SARS-CoV-2 nasal viral load 4 h after irrigation over the three-week study interval. Other endpoints included patient-reported symptom scores assessed using a modified Wisconsin Upper Respiratory Symptom-21 Survey (WURSS-21) and daily temperatures.
No reductions in qPCR-measured nasal cavity viral load were observed in the intervention groups compared to control group (Fig. 1B, Fig. S1F). Similarly, no significant improvements in nasal symptoms were reported in either intervention group compared to the control group (Fig. 1C). No safety signals were observed, e.g., no changes in WURSS-21 smell indices were observed in the irrigation groups to indicate irrigation-mediated spread of SARS-CoV-2 to olfactory epithelia (Fig. S1G), or daily temperature changes (not shown).
Insights into the disparity between the virucidal activity of J&J/S in vitro (Fig. 1A) and the absence of clinical effectiveness (Fig. 1B) emerged from the PK/PD studies of J&J/S in HNE cultures. For these studies, HNE cultures were inoculated at t=0 with D614G SARS-CoV-2 at an MOI of 0.112. Samples for viral qPCR quantitation, utilizing the SARS-CoV-2 nucleoprotein (N1) primers employed in the clinical study, and viral titers were obtained via PBS lavage of HNE culture surfaces 48 h post inoculation (pi)13. At 72 h pi, J&J/S or PBS lavages were administered to HNE culture surfaces, fluids aspirated 10 min later, and titering performed. Note, viral qPCR was not technically accurate in virus-inactivated J&J Baby Shampoo lavage solutions. Importantly, the in vitro J&J/S lavage volume-to-HNE surface area ratio (200 µl/cm2) approximated the ratio in vivo, i.e., 240 ml lavage spread over 150 cm2 nasal surface area14, and the 10 min in vitro J&J/S lavage residence time mimicked the in vivo contact time of lavages with nasal surfaces8,15. Viral qPCR and titering assays were performed on PBS lavages obtained 4 h after the 72 h J&J/S or PBS lavage, i.e., at 76 h pi, and the next day at 96 h pi.
Like previous data1, PBS lavage samples revealed productive SARS-CoV-2 infection of HNE at 48 h pi (Fig. 1D, E), with little change in viral titer at 72 h pi (Fig. 1E, Fig. S1I). Surprisingly, the titers measured in the J&J/S lavage at 72 h pi were also not significantly different from those measured at 48 h in these samples (Fig. 1E, Fig. S1I, J). Furthermore, no differences in qPCR-measured viral load or viral titers from 48 h values were observed in the J&J/S or PBS lavaged HNE cultures over the 76-96 h pi interval (Fig. 1D, E, Fig. S1H, I).
Collectively, these data demonstrate that J&J/S exhibits virucidal activity against SARS-CoV-2 in a test tube in vitro (Fig. 1A) but not when administered onto nasal surfaces in vitro or in vivo (Fig. 1B, D, E). What is noteworthy about SARS-CoV-2-infected nasal surfaces is the continual production and release of SARS-CoV-2 virus onto nasal surfaces over time (Fig. 1E) 1. Accordingly, a virucidal agent must continually remain on nasal surfaces to produce durable and clinically meaningful virucidal activity in the nasal cavity. However, it is difficult to maintain effective concentrations of topical agents on nasal surfaces for two reasons. First, nasal surfaces are protected by a mucociliary transport system that clears nasal surfaces of topically deposited agents within 10 min8,15,16. Second, the nasal surfaces exhibit rapid transepithelial absorption of topically applied agents, a property accessed for drug delivery17-19.
We, therefore, studied the retention of topically applied J&J/S on nasal surfaces. J&J Baby Shampoo is a proprietary mix of agents. Mass spectrometric analysis of J&J/S indicated that the second listed agent after water, and dominant detergent, is cocamidopropyl betaine (CAPB) of varying chain lengths (Fig. S1K). Mass spectrometric analysis of PBS lavages obtained 1 min or 30 min after administration of J&J/S to HNE surfaces revealed that the longer chain CAPB components were absorbed from HNE surfaces within 1 min of administration (Fig. 1F). These data suggest that the failure of J&J/S to reduce SARS-CoV-2 titer in the HNE studies (Fig. 1D, E) reflected the rapid transnasal absorption of the longer chain, more active virucidal components of J&J/S from the lavage fluid (Fig. S1L)11,20.