Reduced Cell Surface Levels of C-C Chemokine Receptor 5 and Immunosuppression in Long Coronavirus Disease 2019 Syndrome.

In an exploratory trial treating "long COVID" with the CCR5-binding antibody leronlimab, we observed significantly increased blood cell surface CCR5 in treated symptomatic responders but not in nonresponders or placebo-treated participants. These findings suggest an unexpected mechanism of abnormal immune downmodulation in some persons that is normalized by leronlimab. Clinical Trials Registration. NCT04678830.

Suppression of human and simian immunodeficiency virus replication with the CCR5-specific antibody Leronlimab in two species.

The CCR5-specific antibody Leronlimab is being investigated as a novel immunotherapy that can suppress HIV replication with minimal side effects. Here we studied the virological and immunological consequences of Leronlimab in chronically CCR5-tropic HIV-1 infected humans (n = 5) on suppressive antiretroviral therapy (ART) and in ART-naïve acutely CCR5-tropic SHIV infected rhesus macaques (n = 4). All five human participants transitioned from daily combination ART to self-administered weekly subcutaneous (SC) injections of 350 mg or 700 mg Leronlimab and to date all participants have sustained virologic suppression for over seven years. In all participants, Leronlimab fully occupied CCR5 receptors on peripheral blood CD4+ T cells and monocytes. In ART-naïve rhesus macaques acutely infected with CCR5-tropic SHIV, weekly SC injections of 50 mg/kg Leronlimab fully suppressed plasma viremia in half of the macaques. CCR5 receptor occupancy by Leronlimab occurred concomitant with rebound of CD4+ CCR5+ T-cells in peripheral blood, and full CCR5 receptor occupancy was found in multiple anatomical compartments. Our results demonstrate that weekly, self-administered Leronlimab was safe, well-tolerated, and efficacious for long-term virologic suppression and should be included in the arsenal of safe, easily administered, longer-acting antiretroviral treatments for people living with HIV-1. Trial Registration: ClinicalTrials.gov Identifiers: NCT02175680 and NCT02355184.

CCR5 Receptor Occupancy Analysis Reveals Increased Peripheral Blood CCR5+CD4+ T Cells Following Treatment With the Anti-CCR5 Antibody Leronlimab.

CCR5 plays a central role in infectious disease, host defense, and cancer progression, thereby making it an ideal target for therapeutic development. Notably, CCR5 is the major HIV entry co-receptor, where its surface density correlates with HIV plasma viremia. The level of CCR5 receptor occupancy (RO) achieved by a CCR5-targeting therapeutic is therefore a critical predictor of its efficacy. However, current methods to measure CCR5 RO lack sensitivity, resulting in high background and overcalculation. Here, we report on two independent, flow cytometric methods of calculating CCR5 RO using the anti-CCR5 antibody, Leronlimab. We show that both methods led to comparable CCR5 RO values, with low background on untreated CCR5+CD4+ T cells and sensitive measurements of occupancy on both blood and tissue-resident CD4+ T cells that correlated longitudinally with plasma concentrations in Leronlimab-treated macaques. Using these assays, we found that Leronlimab stabilized cell surface CCR5, leading to an increase in the levels of circulating and tissue-resident CCR5+CD4+ T cells in vivo in Leronlimab-treated macaques. Weekly Leronlimab treatment in a chronically SIV-infected macaque led to increased CCR5+CD4+ T cells levels and fully suppressed plasma viremia, both concomitant with full CCR5 RO on peripheral blood CD4+ T cells, demonstrating that CCR5+CD4+ T cells were protected from viral replication by Leronlimab binding. Finally, we extended these results to Leronlimab-treated humans and found that weekly 700 mg Leronlimab led to complete CCR5 RO on peripheral blood CD4+ T cells and a statistically significant increase in CCR5+CD4+ T cells in peripheral blood. Collectively, these results establish two RO calculation methods for longitudinal monitoring of anti-CCR5 therapeutic antibody blockade efficacy in both macaques and humans, demonstrate that CCR5+CD4+ T cell levels temporarily increase with Leronlimab treatment, and facilitate future detailed investigations into the immunological impacts of CCR5 inhibition in multiple pathophysiological processes.

Antibody-based CCR5 blockade protects Macaques from mucosal SHIV transmission.

In the absence of a prophylactic vaccine, the use of antiretroviral therapy (ART) as pre-exposure prophylaxis (PrEP) to prevent HIV acquisition by uninfected individuals is a promising approach to slowing the epidemic, but its efficacy is hampered by incomplete patient adherence and ART-resistant variants. Here, we report that competitive inhibition of HIV Env-CCR5 binding via the CCR5-specific antibody Leronlimab protects rhesus macaques against infection following repeated intrarectal challenges of CCR5-tropic SHIVSF162P3. Injection of Leronlimab weekly at 10 mg/kg provides significant but partial protection, while biweekly 50 mg/kg provides complete protection from SHIV acquisition. Tissue biopsies from protected macaques post challenge show complete CCR5 receptor occupancy and an absence of viral nucleic acids. After Leronlimab washout, protected macaques remain aviremic, and adoptive transfer of hematologic cells into naïve macaques does not transmit viral infection. These data identify CCR5 blockade with Leronlimab as a promising approach to HIV prophylaxis and support initiation of clinical trials.

Case study of a critically ill person with COVID-19 on ECMO successfully treated with leronlimab.

The number of confirmed cases of infection with SARS-CoV-2, the virus causing Coronavirus disease 2019 (COVID-19), continues to increase and is associated with substantial morbidity and mortality in virtually every country in the world. Although in the long-term mass vaccinations remains the most promising approach to control the pandemic, evidence suggests that new variants of the virus have emerged that may be able to evade the immune responses triggered by current vaccines. Therefore despite the recent approval of a number of SARS-CoV-2 vaccines there remains considerable urgency for effective treatments for COVID-19. Severe-to-critical COVID-19 has been shown to be associated with a dysregulated host immune response to SARS-CoV-2 with elevated levels of C-C chemokine receptor type 5 (CCR5) ligands including chemokine C-C ligands 3, 4, 5, as well as interleukins 6 and 10. Leronlimab, a CCR5-specific humanised IgG4 monoclonal antibody originally developed for the treatment of HIV has been studied for the treatment of COVID-19. In the TEMPEST trial which compared leronlimab to placebo in subjects with mild-to-moderate COVID-19, a post hoc analysis showed that leronlimab led to improvements from baseline in National Early Warning Score 2 (NEWS2) at Day 14 in the sub-set of people with more severe disease. Data has also been released on a further ongoing, randomized, placebo-controlled phase 3 registrational trial of leronlimab in 394 people with severe-to-critical COVID-19. The results show that Day 28 mortality was reduced (P â€‹= â€‹0.0319) in the subset of participants receiving leronlimab plus other pre-specified commonly used COVID-19 treatments including dexamethasone administered as part of their standard of care (SOC) compared to participants receiving placebo plus other pre-specified commonly used COVID-19 treatments including dexamethasone as part of their SOC. Several cases have recently been reported demonstrated that treatment with leronlimab restores immune function and achieves clinical improvement in people with critical COVID-19. Here we report on a further case of a critically ill person who was treated with leronlimab. This person had been on extracorporeal membrane oxygenation (ECMO) for an extended period of time before receiving 4 doses of leronlimab. The male subject received his first dose of leronlimab on Day 79 of hospitalization he was weaned off ECMO by Day 84 and discharged from the ECMO intensive care unit on Day 91.

Disruption of CCR5 signaling to treat COVID-19-associated cytokine storm: Case series of four critically ill patients treated with leronlimab.

Coronavirus disease 2019 (COVID-19) is associated with considerable morbidity and mortality. The number of confirmed cases of infection with SARS-CoV-2, the virus causing COVID-19 continues to escalate with over 70 million confirmed cases and over 1.6 million confirmed deaths. Severe-to-critical COVID-19 is associated with a dysregulated host immune response to the virus, which is thought to lead to pathogenic immune dysregulation and end-organ damage. Presently few effective treatment options are available to treat COVID-19. Leronlimab is a humanized IgG4, kappa monoclonal antibody that blocks C-C chemokine receptor type 5 (CCR5). It has been shown that in patients with severe COVID-19 treatment with leronlimab reduces elevated plasma IL-6 and chemokine ligand 5 (CCL5), and normalized CD4/CD8 ratios. We administered leronlimab to 4 critically ill COVID-19 patients in intensive care. All 4 of these patients improved clinically as measured by vasopressor support, and discontinuation of hemodialysis and mechanical ventilation. Following administration of leronlimab there was a statistically significant decrease in IL-6 observed in patient A (p=0.034) from day 0-7 and patient D (p=0.027) from day 0-14. This corresponds to restoration of the immune function as measured by CD4+/CD8+ T cell ratio. Although two of the patients went on to survive the other two subsequently died of surgical complications after an initial recovery from SARS-CoV-2 infection.

CCR5 inhibition in critical COVID-19 patients decreases inflammatory cytokines, increases CD8 T-cells, and decreases SARS-CoV2 RNA in plasma by day 14.

OBJECTIVE: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now a global pandemic. Emerging results indicate a dysregulated immune response. Given the role of CCR5 in immune cell migration and inflammation, we investigated the impact of CCR5 blockade via the CCR5-specific antibody leronlimab on clinical, immunological, and virological parameters in severe COVID-19 patients. METHODS: In March 2020, 10 terminally ill, critical COVID-19 patients received two doses of leronlimab via individual emergency use indication. We analyzed changes in clinical presentation, immune cell populations, inflammation, as well as SARS-CoV-2 plasma viremia before and 14 days after treatment. RESULTS: Over the 14-day study period, six patients survived, two were extubated, and one discharged. We observed complete CCR5 receptor occupancy in all donors by day 7. Compared with the baseline, we observed a concomitant statistically significant reduction in plasma IL-6, restoration of the CD4/CD8 ratio, and resolution of SARS-CoV2 plasma viremia (pVL). Furthermore, the increase in the CD8 percentage was inversely correlated with the reduction in pVL (r = -0.77, p = 0.0013). CONCLUSIONS: Our study design precludes clinical efficacy inferences but the results implicate CCR5 as a therapeutic target for COVID-19 and they form the basis for ongoing randomized clinical trials.

PRO 140, a monoclonal antibody targeting CCR5, as a long-acting, single-agent maintenance therapy for HIV-1 infection.

Background PRO 140 is a humanized monoclonal antibody targeting CCR5 with potent antiviral activity in patients with CCR5-tropic HIV-1 infection. In phase 2b studies, we evaluated the long-term efficacy, safety, and tolerability of PRO 140 monotherapy in maintaining viral suppression for over 24 months in patients who were stable on combination antiretroviral therapy on entry into the trials. Methods and Results Forty-one adult patients, infected exclusively with CCR5-tropic HIV-1 with viral loads <50 copies/mL, were switched from daily oral combination ART regimens to weekly PRO 140 monotherapy for 12 weeks. Participants who completed 12 weeks of treatment without experiencing virologic rebound were allowed to self-administer PRO 140 as a 350 mg subcutaneous injection weekly, for up to an additional 160 weeks. Participants were monitored bi-weekly for one year, and every four weeks thereafter for virologic rebound. PRO 140 provided virologic suppression in 23/41 (56.1%) participants for 12 weeks and was well tolerated. Ten (10) participants are currently ongoing, of which nine participants have completed more than two years of monotherapy treatment (47-129 weeks). Participants experiencing virologic rebound achieved full viral suppression upon re-initiation of oral combination ART regimen. Anti-PRO 140 antibodies were not detected in any patient, and no drug-related major adverse events or treatment discontinuations were reported. Conclusions PRO 140 has a potential to address an unmet need for a long-acting, single-agent, maintenance regimen for HIV infection in selected patients. Studies are underway to determine host and/or virologic factors that may predict treatment success on PRO 140 monotherapy. Moreover, it has sufficient potency for a prolonged period of monotherapy that it would be an excellent component of a multi long-acting drug combination.