There are currently no products approved by the FDA for the prevention of CRS/cytokine storm associated with COVID-19. There are numerous products currently in development for COVID-19 which can be broadly categorized as direct-acting antivirals, immunomodulators, and other preventative strategies such as vaccines. In May 2020, remdesivir (VEKLURY®) (a direct-acting antiviral) received EUA by FDA for COVID-19 based on results from the NIAID sponsored ACTT-1 trial. In this trial, remdesivir demonstrated improvement in the primary endpoint of time to recovery, reducing this measurement by four days (11 days in the remdesivir cohort vs. 15 days in the placebo cohort). There was no difference in mortality between the remdesivir treated cohort and placebo. Other direct-acting antiviral agents such as lopinavir/ritonavir and hydroxychloroquine (with or without a macrolide antibiotic) have not demonstrated efficacy in multiple randomized controlled trials. In addition, no immunomodulator therapy has proven efficacy in a randomized, controlled clinical trial in the setting of COVID-19 and the two leading IL-6 inhibitors, Actemra (tocilizumab) and Kevzara (sarilumab) both recently failed to demonstrate efficacy in randomized, placebo-controlled studies in COVID-19 patients. Although steroids have demonstrated a mortality benefit in a randomized trial in the United Kingdom (RECOVERY Trial), the benefit of steroids appears to be in a subset of patients that are non-diabetic, have significantly elevated c-reactive protein (CRP) levels, and on invasive mechanical ventilation (IMV) prior to therapy.
We believe that, as an upstream regulator of cytokine storm, GM-CSF neutralization with lenzilumab may offer advantages over other immunomodulator strategies that either target other downstream cytokines such as IL-1, IL-6, CCR5, MCP-1, IP-10, TNF-α, or MIP-1α (the ligand for the CCR5 receptor) or are broadly immune-suppressive and target cytokine signaling pathways non-selectively through JAK inhibition or steroids which have well documented lympholytic properties. In addition, we believe, lenzilumab is the only immunomodulator that was in an active clinical trial in a non-COVID indication to prevent cytokine storm prior to embarking upon the Phase III COVID-19 trial. According to clintrials, lenzilumab is currently the only agent in an active Phase III trial targeting GM-CSF. In addition, lenzilumab may have additional benefits on T-cell function as demonstrated in preclinical models with CAR-T.
Lenzilumab is being studied in patients with confirmed COVID 19 infection and pneumonia who are hospitalized not requiring IMV and blood oxygen (Sp02) levels below 94%. We believe the market potential for lenzilumab to be significant as shown in the following graphic. According to the COVID Tracking Project, as of August 30, 2020, daily hospitalizations are approximately 1,000 new patients per day.
Development and implementation of individualized treatments based on T-cell therapies has the potential to revolutionize the fight against cancer. Three CAR-T therapies have been approved by the FDA, Kite’s Yescarta, Tecartus and Novartis’s Kymriah, to treat forms of B-cell cancers such as various types of Non-Hodgkin Lymphoma (“NHL”), including DLBCL, mantle cell lymphoma and acute lymphoblastic leukemia (“ALL”) in patients that have failed two or more lines of systemic therapy. According to the Surveillance, Epidemiology, and End Results (“SEER”) program of the National Cancer Institute, it is estimated that nearly 20,000 patients per year in the U.S. will die from all forms of Non-Hodgkin Lymphoma, including patients with relapsed or refractory (r/r) B-cell NHL and ALL. Common side effects of CAR-T therapy include CRS and Neurologic Toxicities (NT). We believe agents that address the CRS and NT side effects of CAR-T therapies will greatly expand the use of CAR-T therapies.
The global CAR-T therapy market is projected to grow to greater than $2 billion in 2021, with continued growth up to $8.5 billion in 2028, according to ‘Evaluatepharma’.
In addition to CAR-T therapy, we are advancing our platform for GM-CSF suppression for a broad range of other T-cell engaging therapies, including for the prevention and/or treatment of GvHD in patients undergoing allogeneic HSCT, which involves transferring stem cells from a healthy donor to the patient. Allogeneic HSCT has demonstrated effectiveness in treating hematological cancers, and as a result the overall number of allogeneic HSCT treatments continues to increase annually in the U.S. and in Europe. Unfortunately, many of these treatments lead to serious side-effects and have ample room for improved efficacy.
We believe that GM-CSF neutralization with lenzilumab has the potential to prevent or reduce GvHD without compromising, and potentially improving, the beneficial graft-versus-leukemia (“GvL”) effect in patients undergoing allogeneic HSCT, thereby making allogeneic HSCT safer. Allogeneic HSCT is a potentially curative therapy for patients with hematological cancers. Although a potentially life-saving treatment for patients suffering from hematological cancers, between 40-60% of patients receiving HSCT treatments experience acute or chronic GvHD, which together carries a 50% mortality rate. After being transplanted into the patient, donor-derived T cells are responsible for mediating the beneficial GvL effect. In many cases, however, donor-derived T cells that remain within the graft itself have also been linked to destruction of healthy tissue in the patient (the host), with particular risk of destroying cells in the patient’s skin, gut, and liver, resulting in GvHD. Although depleting donor grafts of T cells can prevent or reduce the risk of GvHD, this results in a reduced GvL effect, thereby having a detrimental impact on the efficacy of the allogeneic HSCT treatment itself and leading to increased relapse rates. We expect that the use of allogeneic HSCT may be hampered by GvHD complications. A recent study published in ‘blood advances’ an official journal of the American Society of Hematology, suggests that neutralizing or blocking GM-CSF may limit or prevent GvHD in the gastrointestinal tract (Gartlan, K., et al, October 8, 2019, vol 3, no.19).
There are currently no FDA-approved agents for the prevention of GvHD, and there is a significant unmet medical need for an agent that can uncouple the beneficial GvL effect from harmful GvHD. At this time, pre-conditioning regimens for HSCT treatments vary significantly by treatment centers, including by unapproved, or “off-label”, use of agents that have been approved by the FDA for other uses only. We believe there to be a significant unmet medical need and lenzilumab, if proven to be able to prevent GvHD in allogeneic HSCTs, may offer a solution.