On November 13, Enlivex (NASDAQ: ENLV) announced that the first patient has been dosed in its Phase I/II clinical trial of Allocetra. The novel off-the-shelf cell therapy is designed to help break through the immune-suppressing tumor microenvironment – a key roadblock rendering potent immunotherapies less effective against solid cancers – to render those tough-to-treat cancers more responsive to these treatments.
After a growing body of preclinical data demonstrated Allocetra’s potential to prolong survival duration and increase survival probability in mice, the Phase I/II studies are an important next step in evaluating their efficacy in humans.
Immunotherapies Tap the Body’s Own Cancer-Fighting Capabilities – But Solid Cancers Remain Resistant
As the field of immunotherapy makes strides, solid tumors continue to elude these novel treatments largely due to their complex and ever-adapting “tumor microenvironments.” These microenvironments leverage a range of immune-suppressing mechanisms that counteract the potent effects immunotherapies have had on skin and blood cancers.
Chimeric Antigen Receptor (CAR)-T therapies, for example, have demonstrated a success rate as high as 90% for refractory B lymphocytic leukemia but as low as 17% for solid cancers. Novartis AG’s (NYSE: NVS) Kymriah, the first CAR-T therapy to receive approval from the Food and Drug Administration, has since shown a durable remission and long-term survival rate, with as many as 55% of treated patients still alive more than five years later compared to the standard disease prognosis of 10% to 25%.
The reason for this difference is largely due to the range of mechanisms tumors use to resist or evade the immune system including disguising themselves as healthy cells, releasing immune suppressing signals, and blocking immune cells from getting into the core of the tumor. The more the tumor grows, the stronger these immunosuppressive mechanisms get – making it harder for the immune system to detect it.
This makes tumors some of the least responsive cells to immunotherapies of all kinds as that microenvironment counteracts the effects of the treatment. Even in cases where tumors do initially respond to the drug, they adapt to resist it and the once-helpful immunotherapy is rendered ineffective.
AllocetraTM Uses Cell Reprogramming to Simultaneously Weaken Tumor Microenvironments and Strengthen the Immune Response
Enlivex’s lead drug candidate, AllocetraTM, was developed as an off-the-shelf cell therapy that reprograms macrophages, the immune cells responsible for killing infected or harmful cells in the body. In cancer patients, macrophages often become reprogrammed out of their homeostatic state of relatively stable equilibrium so that they not only stop recognizing tumors as harmful but become weaponized by cancer to fend off other immune cells trying to attack the tumor.
This reprogramming is a key mechanism of the resistance that cancer develops against immunotherapies. So the goal with Allocetra is to introduce healthy donor cells that have been modified with an “eat me” signal on their surface to trigger the non-homeostatic macrophages to engulf them. Once eaten, the donor cells are able to bring those macrophages back to a homeostatic state.
Early preclinical results show that this process, on a stand-alone basis, is enough to increase survival duration and overall survival in mice with solid cancers similarly to current FDA-approved immune checkpoint inhibitors (anti-PD1 like Merck & Co Inc.’s (NYSE: MRK) Keytruda, BMS’s Opdivo and Yervoy). But even more impressive was the synergistic effect of administering Allocetra in combination with these immune checkpoint inhibitors, which led to up to 100% complete remission of the cancer in the mice.
The Start of Human Trials Marks a Key Milestone in Allocetra’s Development
The next step for this new cell therapy is to test whether these promising preclinical results will translate to human studies. This month, Enlivex initiated a Phase I/II trial to do just that. After receiving approval from the Israeli Ministry of Health in October, Enlivex began dosing the first patients in the trial in November.
The trial will enroll up to 48 patients with advanced solid tumors to evaluate the safety and tolerability of Allocetra as well as its preliminary efficacy, as measured by overall response rate and survival. Patients will be divided into two groups – stage one and stage two – with stage one patients receiving escalating doses of Allocetra as a standalone treatment while stage two patients will receive three injections of Allocetra combined with an anti-PD1 checkpoint inhibitor.
As Enlivex enrolls more patients into the trial in 2023, it hopes to have top-line Phase I/II data by the second half of the year.
As part of a new generation of companies representing the future of cell therapy – off-the-shelf, highly scalable and low COGS “beyond CAR-T” cell therapies – Enlivex is focused on a highly differentiated novel immunotherapeutic mechanism – macrophage homeostasis. Macrophage homeostasis is severely disrupted by certain diseases states, and such imbalance is critical to the progression of the diseases. Allocetra has the potential to introduce highly-effective, low-cost allogeneic cell therapies for life-threatening clinical indications that are defined as "unmet medical needs", including sepsis – one of the leading causes of mortality, and oncology, through restoration of macrophage homeostasis. Enlivex is led by a seasoned management team who founded PROLOR Biotech and led it to a successful $560 financial exit and a partnership with Pfizer. PROLOR’s lead product, now named NGenla® by Pfizer, recently received marketing approval in Australia, Canada, Japan and the EU.
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Safe Harbor Statement: This press release contains forward-looking statements, which may be identified by words such as “expects,” “plans,” “projects,” “will,” “may,” “anticipates,” “believes,” “should,” “would”, “could,” “intends,” “estimates,” “suggests,” “has the potential to” and other words of similar meaning, including statements regarding expected cash balances, market opportunities for the results of current clinical studies and preclinical experiments, the effectiveness of, and market opportunities for, ALLOCETRATM programs. All such forward-looking statements are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Investors are cautioned that forward-looking statements involve risks and uncertainties that may affect Enlivex’s business and prospects, including the risks that Enlivex may not succeed in generating any revenues or developing any commercial products; that the products in development may fail, may not achieve the expected results or effectiveness and/or may not generate data that would support the approval or marketing of these products for the indications being studied or for other indications; that ongoing studies may not continue to show substantial or any activity; and other risks and uncertainties that may cause results to differ materially from those set forth in the forward-looking statements. The results of clinical trials in humans may produce results that differ significantly from the results of clinical and other trials in animals. The results of early-stage trials may differ significantly from the results of more developed, later-stage trials. The development of any products using the ALLOCETRATM product line could also be affected by a number of other factors, including unexpected safety, efficacy or manufacturing issues, additional time requirements for data analyses and decision making, the impact of pharmaceutical industry regulation, the impact of competitive products and pricing and the impact of patents and other proprietary rights held by competitors and other third parties. In addition to the risk factors described above, investors should consider the economic, competitive, governmental, technological and other factors discussed in Enlivex’s filings with the Securities and Exchange Commission, including in the Company’s most recent Annual Report on Form 20-F filed with the Securities and Exchange Commission. The forward-looking statements contained in this press release speak only as of the date the statements were made, and we do not undertake any obligation to update forward-looking statements, except as required under applicable law.