They are called “Natural Killer” (NK) cells for a reason. These cytotoxic lymphocytes, a part of innate immunity, are the body’s cellular “boots on the ground,” capable of swiftly and ferociously lysing tumor and virally-infected cells. While NK cells were among the earliest cellular immunotherapies in clinical trials, most failed at that time. However, a greater understanding of NK biology, coupled with the emergence of new technologies are leading to a resurgence of NK cell-based immunotherapies.
The 10th Annual Innate Killer Summit this past March highlighted the clinical successes, novel research approaches, and updated manufacturing of NK therapies. For example, some strategies activate a patient’s own NK cells in vivo to enhance their cancer-killing potency. Several companies are pursuing off-the-shelf NK therapeutics. In one case, such allogeneic NK cells are engineered with a B cell-targeting/depleting monoclonal antibody (mAb) as a treatment for autoimmune disease. Another strategy genetically engineers allogeneic NK cells with chimeric antigen receptors (CARs). Also on the radar is the development of induced pluripotent stem cells (iPSC) that can escape host immune attack because of “stealth-like” modifications. Many clinical trials are underway exploiting these emerging NK therapies, particularly against a host of cancers as well as autoimmune diseases.
Mark Lowdell, PhD
CSO, CMO, INmune Bio
“The innate immune response is critical in the control of many cancers and NK cells have been used successfully in adoptive therapies in the past,” remarks Mark Lowdell, PhD, CSO and CMO, INmune Bio. “The challenge for NK therapies is the sheer number of NK cells needed since they rarely expand in vivo, and they have a short half-life compared to T cells.”
The company is pioneering the therapeutic approach of activating a patient’s own NK cells to make them more robust and “memory-like.” Lowdell explains, “First, we have chosen to prime NK cells in vivo so we don’t have to manufacture and deliver enormous doses of NK cells derived from healthy donors or iPSC lines. Second, by priming in vivo, we can activate NK cells which are already in the tumor microenvironment, so we don’t have to rely upon an adoptive NK cell product invading the tumor from the peripheral blood.”
To accomplish such priming, oncologists infuse patients with the pharmaceutical-grade INKmune
, a replication-incompetent tumor cell product, which ligates multiple receptors on resting NK cells. This leads to the cells’ activation/differentiation into tumor-killing memory-like NK cells (mINK cells). Lowdell elaborates, “INKmune cells are cleared in vivo in 3–5 days after injection. During this time, they bind to the patient’s NK cells. This binding leads to trogocytosis of membrane rafts from the INKmune cells into the membranes of the NK cells. Thus, even after the INKmune cells have been cleared from the circulation, the activating ligands are present on circulating NK cells and are presented from NK cell to NK cell, extending the duration of exposure. These resting NK cells then acquire the functional characteristics of the primed NK cells.”
The company is currently in Phase II trials targeting metastatic castration-resistant prostate cancer. Lowdell adds, “Patients in our trials have shown very prolonged NK cell activation in vivo–up to 3 months after the last INKmune treatment. We attribute this to the continued presentation of INKmune membranes to resting NK cells in vivo. We have pre-clinical data on ovarian cancer, lymphoma, and renal cell cancer. One or more of these will be trial targets in the future.”
Using “bacteria” and “immunotherapy” in the same sentence may garner puzzled looks from scientists, but there is accumulating evidence that attenuated bacteria may modulate the immune system (including NK cells) and help fight cancer.1 In the early 1890s, William Coley, MD, utilized intact, heat-killed Streptococcus pyogenes and Bacillus prodigiosus (aka Serratia marcescens) and found some tumors regressed following injections into patients. Over the past 30 years, other studies have assessed attenuated, replicating bacteria (lacking lipopolysaccharide [LPS] endotoxin) to infect and kill tumor cells.
However, Indaptus Therapeutics is pursuing a different bacterial immunotherapy approach that they believe will more fully engage not only NK cells but also the greater immune system to trigger antitumor and antiviral activity. Michael Newman, PhD, founder and CSO, explains, “Broad activation of both innate and adaptive immune pathways has always been challenging due to the potential for unacceptable side effects, particularly since most current therapies depend on continuous exposure. By using attenuated and killed, non-pathogenic bacteria to deliver multiple innate and adaptive immune agonists, Indaptus leverages the well-established short half-life of intravenously administered bacteria to produce a very short, or pulsed, but extremely broad systemic activation of both innate and adaptive anti-tumor immune pathways.”
Michael Newman, PhD
Founder, CSO
Indaptus Therapeutics
One of the company’s lead product candidates, Decoy20, was produced from a strain of Escherichia coli using a proprietary process Newman developed that not only kills and stabilizes the bacteria, but it also retains a very limited level of LPS-endotoxin activity. According to Newman, the immunotherapy works by passively targeting pulse-priming of the immune system. He elucidates, “Decoy20 is currently being tested in a US clinical trial (Phase I) in cancer patients with advanced solid tumors, including colorectal, liver, pancreatic, urothelial, non-small cell lung, and head and neck cancers. We have already demonstrated tolerability of weekly administration, confirmed the predicted short half-life of the Decoy20 product, and produced evidence of exceptionally broad, but transient, systemic immune activation. A combination study with an approved anti-PD-1 product is planned.”
Newman is encouraged by the findings. “We look forward to reporting the results of our current clinical trial and believe that our extremely novel approach will contribute to better outcomes for patients with largely incurable advanced malignancies.”
The killed bacteria-based Decoy20 therapy by Indaptus Therapeutics delivers a systemic pulse of innate and adaptive immune cell activators. [Michael Newman, PhD]
Autoimmune diseases often develop when B cells produce antibodies that attack self tissue. Artiva Biotherapeutics is focusing on treating autoimmune diseases utilizing their allogeneic, off-the-shelf NK cells, AlloNK®.
Fred Aslan, MD
President and CEO
Artiva Biotherapeutics
Fred Aslan, MD, president and CEO, says the technological approach was built on earlier studies for oncological and autoimmune applications that employed autologous CAR T cells directed to deplete B cells for a so-called “immune reset.” He points out, “We had already demonstrated that AlloNK coupled with a specific monoclonal antibody could eliminate all patient B cells and help drive an aggressive B-cell cancer into remission. We very quickly realized that our approach also could be geared towards treating autoimmunity, a very high impact area.”
“There are several major advantages for utilizing NK cells,” notes Aslan. “First, they are ‘off-the-shelf’ products contrary to the need to take and modify cells from a specific patient. Second, they are cheaper to produce (by an order of magnitude) as well as more flexible to scale up. Third, they avoid common CAR T side effects of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS).”
The company pairs their AlloNK cells in combination with rituximab, a B cell-targeting mAb. Aslan emphasizes, “Importantly, we are working on a very well-understood mechanism that is called antibody-dependent cellular cytotoxicity (ADCC). We usually think that these mAbs do the killing, but they do not. Rather, they recruit the NK cells to do the killing. But most of us do not have high enough numbers of robust NK cells to drive the most efficacy from the mAbs. So, our hypothesis is that by introducing high doses of NK cells exogenously, we can really drive and enhance the activity of the mAbs we give together with our therapy.”
To create the therapeutic, Artiva sources specially selected NK cells from umbilical cords and prepares them in an infusion-ready formulation capable of being given in a 5- to 10- minute intravenous push at the bedside. “It’s as close to a biologic cell therapy as has ever been done,” suggests Aslan.
Mallory Murray, PhD, senior scientist in pharmacology and translational science at Artiva Biotherapeutics, evaluates the ADCC (antibody-dependent cellular cytotoxicity) activity of AlloNK on target cells by fluorescent microscopy. [Jessica Yingling]
In addition to its ongoing oncological programs, the company currently has a company-sponsored Phase I/Ib study for the treatment of systemic lupus erythematosus (SLE, with or without lupus nephritis) and an investigator-initiated basket study that includes patients with rheumatoid arthritis, pemphigus vulgaris, vasculitis, granulomatosis, or SLE. “We look forward to generating data from these clinical trials in autoimmune disease,” states Aslan.
While an exciting clinical immunotherapy, CAR T-cell therapeutics also present significant challenges in the individual and time-consuming preparation for patients as well as the potential for severe adverse effects. An emerging approach to overcome these challenges is the use of CAR NK-cell therapeutics.
Dinesh Kundu, MBBS, CEO and co-founder East Ocyon Bio, an India- based biotech start-up, explains, “CAR NK therapies are derived from healthy donor cells, allowing for an off-the-shelf, allogeneic product that can be produced at scale. A single donor batch can yield up to 20 doses currently (and maybe hundreds of doses in the future), significantly reducing the per-dose manufacturing cost. This scalability is particularly beneficial in India and other low- and middle-income countries where the high volume of cancer cases demands rapid and widespread treatment availability. The off-the-shelf nature of CAR NK therapies also minimizes the turnaround time from cell collection to treatment, which is crucial for patients with aggressive cancers.”
Renu Kundu, PhD (left), Director and Co-founder, Dinesh Kundu, MBBS, (right), CEO and Co-founder, East Ocyon Bio
Kundu says CAR NK cells exhibit a superior safety profile compared to CAR T cells. “They present a lower risk of severe adverse effects such as CRS and graft-versus-host disease (GvHD), making them a safer option for a broader patient population.”
The company’s technology engineers NK cells derived from peripheral blood with a CAR that targets PD-L1, a protein frequently overexpressed on tumor cells that aids in immune evasion. Kundu elaborates, “The CAR construct is introduced into NK cells using a baboon pseudotype gamma retroviral vector—a specialized vector that enhances gene transfer efficiency. The baboon envelope pseudotype improves the tropism for NK cells, ensuring robust and stable CAR expression, which is essential for effective tumor targeting.”
Director and co-founder Renu Kundu, PhD, indicates that preclinical studies have already demonstrated significant cytotoxicity against ovarian and other cancer cell lines. “We are progressing toward early-phase clinical trials in collaboration with Indian research hospitals and other partners. Simultaneously, we recognize the importance of staying at the forefront of global innovation. To achieve this, we will continue forging strategic partnerships with top-tier universities and biotech centers in the U.S. and Europe.”
Nikolaus Trede, MD, PhD
Sr. Vice President
Century Therapeutics
“NK cells are potent killers but have limited capacity to expand and persist, which contributes to a predicted safer profile,” observes Nikolaus Trede, MD, PhD, senior vice president and head of clinical development, Century Therapeutics. The company is developing an allogeneic (off-the-shelf), iPSC-derived cell therapy platform.
Trede informs, “The benefit of an ‘off-the-shelf’ approach is the potential to overcome the limitations of first-generation, autologous cell therapies by providing readily available treatment more quickly, reliably, at greater scale, and to a broader patient population without the need of washout of immunosuppressive drugs for apheresis and manufacturing. On the flip side, the inherent challenge of allogeneic cell therapy is the potential for rejection by the host immune system.”
To address this obstacle, the company creates genetically modified NK cells to create “advanced soldiers,” termed iNK. Trede expands, “Our cells are engineered to escape recognition and destruction and thus co-exist with the host immune system. That feat is accomplished by engineering ‘stealth features’ that includes eliminating HLA-I and HLA-II to avoid allo-recognition by T cells coupled with the overexpression of HLA-E to block endogenous NK cells that would be activated by the absence of HLA-I.”
Century is clinically assessing one of the first Allo-Evasion
CAR-iNK cell products, CNTY-101. The CD19-targeted CAR-iNK cell therapy has six precision gene edits and is in Phase I development for B-cell mediated autoimmune diseases and lymphoma.
In Century Therapeutics’ laboratory space at One uCity Square in Philadelphia, PA, scientists are developing allogeneic, iPSC-derived cell therapies with the potential to overcome the limitations of first-generation autologous cell therapies. [David Rosen]
Trede reports, “We have shown that in the presence of a restored immune system, infusions with CNTY-101 have the same persistence profile as infusions given when endogenous T and NK cells are depressed under the influence of lymphodepletion. While these results are encouraging, Century continues to innovate with even more comprehensive ways to suppress endogenous NK cells.”
Reference
The post The Body’s Delta Force: Natural Killer Cells Re-Emerge appeared first on GEN - Genetic Engineering and Biotechnology News.
The 10th Annual Innate Killer Summit this past March highlighted the clinical successes, novel research approaches, and updated manufacturing of NK therapies. For example, some strategies activate a patient’s own NK cells in vivo to enhance their cancer-killing potency. Several companies are pursuing off-the-shelf NK therapeutics. In one case, such allogeneic NK cells are engineered with a B cell-targeting/depleting monoclonal antibody (mAb) as a treatment for autoimmune disease. Another strategy genetically engineers allogeneic NK cells with chimeric antigen receptors (CARs). Also on the radar is the development of induced pluripotent stem cells (iPSC) that can escape host immune attack because of “stealth-like” modifications. Many clinical trials are underway exploiting these emerging NK therapies, particularly against a host of cancers as well as autoimmune diseases.
NK booster
Mark Lowdell, PhD
CSO, CMO, INmune Bio
“The innate immune response is critical in the control of many cancers and NK cells have been used successfully in adoptive therapies in the past,” remarks Mark Lowdell, PhD, CSO and CMO, INmune Bio. “The challenge for NK therapies is the sheer number of NK cells needed since they rarely expand in vivo, and they have a short half-life compared to T cells.”
The company is pioneering the therapeutic approach of activating a patient’s own NK cells to make them more robust and “memory-like.” Lowdell explains, “First, we have chosen to prime NK cells in vivo so we don’t have to manufacture and deliver enormous doses of NK cells derived from healthy donors or iPSC lines. Second, by priming in vivo, we can activate NK cells which are already in the tumor microenvironment, so we don’t have to rely upon an adoptive NK cell product invading the tumor from the peripheral blood.”
To accomplish such priming, oncologists infuse patients with the pharmaceutical-grade INKmune
The company is currently in Phase II trials targeting metastatic castration-resistant prostate cancer. Lowdell adds, “Patients in our trials have shown very prolonged NK cell activation in vivo–up to 3 months after the last INKmune treatment. We attribute this to the continued presentation of INKmune membranes to resting NK cells in vivo. We have pre-clinical data on ovarian cancer, lymphoma, and renal cell cancer. One or more of these will be trial targets in the future.”
Bacterial immune activation
Using “bacteria” and “immunotherapy” in the same sentence may garner puzzled looks from scientists, but there is accumulating evidence that attenuated bacteria may modulate the immune system (including NK cells) and help fight cancer.1 In the early 1890s, William Coley, MD, utilized intact, heat-killed Streptococcus pyogenes and Bacillus prodigiosus (aka Serratia marcescens) and found some tumors regressed following injections into patients. Over the past 30 years, other studies have assessed attenuated, replicating bacteria (lacking lipopolysaccharide [LPS] endotoxin) to infect and kill tumor cells.
However, Indaptus Therapeutics is pursuing a different bacterial immunotherapy approach that they believe will more fully engage not only NK cells but also the greater immune system to trigger antitumor and antiviral activity. Michael Newman, PhD, founder and CSO, explains, “Broad activation of both innate and adaptive immune pathways has always been challenging due to the potential for unacceptable side effects, particularly since most current therapies depend on continuous exposure. By using attenuated and killed, non-pathogenic bacteria to deliver multiple innate and adaptive immune agonists, Indaptus leverages the well-established short half-life of intravenously administered bacteria to produce a very short, or pulsed, but extremely broad systemic activation of both innate and adaptive anti-tumor immune pathways.”
Michael Newman, PhD
Founder, CSO
Indaptus Therapeutics
One of the company’s lead product candidates, Decoy20, was produced from a strain of Escherichia coli using a proprietary process Newman developed that not only kills and stabilizes the bacteria, but it also retains a very limited level of LPS-endotoxin activity. According to Newman, the immunotherapy works by passively targeting pulse-priming of the immune system. He elucidates, “Decoy20 is currently being tested in a US clinical trial (Phase I) in cancer patients with advanced solid tumors, including colorectal, liver, pancreatic, urothelial, non-small cell lung, and head and neck cancers. We have already demonstrated tolerability of weekly administration, confirmed the predicted short half-life of the Decoy20 product, and produced evidence of exceptionally broad, but transient, systemic immune activation. A combination study with an approved anti-PD-1 product is planned.”
Newman is encouraged by the findings. “We look forward to reporting the results of our current clinical trial and believe that our extremely novel approach will contribute to better outcomes for patients with largely incurable advanced malignancies.”
The killed bacteria-based Decoy20 therapy by Indaptus Therapeutics delivers a systemic pulse of innate and adaptive immune cell activators. [Michael Newman, PhD]
Autoimmunity reset
Autoimmune diseases often develop when B cells produce antibodies that attack self tissue. Artiva Biotherapeutics is focusing on treating autoimmune diseases utilizing their allogeneic, off-the-shelf NK cells, AlloNK®.
Fred Aslan, MD
President and CEO
Artiva Biotherapeutics
Fred Aslan, MD, president and CEO, says the technological approach was built on earlier studies for oncological and autoimmune applications that employed autologous CAR T cells directed to deplete B cells for a so-called “immune reset.” He points out, “We had already demonstrated that AlloNK coupled with a specific monoclonal antibody could eliminate all patient B cells and help drive an aggressive B-cell cancer into remission. We very quickly realized that our approach also could be geared towards treating autoimmunity, a very high impact area.”
“There are several major advantages for utilizing NK cells,” notes Aslan. “First, they are ‘off-the-shelf’ products contrary to the need to take and modify cells from a specific patient. Second, they are cheaper to produce (by an order of magnitude) as well as more flexible to scale up. Third, they avoid common CAR T side effects of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS).”
The company pairs their AlloNK cells in combination with rituximab, a B cell-targeting mAb. Aslan emphasizes, “Importantly, we are working on a very well-understood mechanism that is called antibody-dependent cellular cytotoxicity (ADCC). We usually think that these mAbs do the killing, but they do not. Rather, they recruit the NK cells to do the killing. But most of us do not have high enough numbers of robust NK cells to drive the most efficacy from the mAbs. So, our hypothesis is that by introducing high doses of NK cells exogenously, we can really drive and enhance the activity of the mAbs we give together with our therapy.”
To create the therapeutic, Artiva sources specially selected NK cells from umbilical cords and prepares them in an infusion-ready formulation capable of being given in a 5- to 10- minute intravenous push at the bedside. “It’s as close to a biologic cell therapy as has ever been done,” suggests Aslan.
Mallory Murray, PhD, senior scientist in pharmacology and translational science at Artiva Biotherapeutics, evaluates the ADCC (antibody-dependent cellular cytotoxicity) activity of AlloNK on target cells by fluorescent microscopy. [Jessica Yingling]
In addition to its ongoing oncological programs, the company currently has a company-sponsored Phase I/Ib study for the treatment of systemic lupus erythematosus (SLE, with or without lupus nephritis) and an investigator-initiated basket study that includes patients with rheumatoid arthritis, pemphigus vulgaris, vasculitis, granulomatosis, or SLE. “We look forward to generating data from these clinical trials in autoimmune disease,” states Aslan.
CAR-NK therapy
While an exciting clinical immunotherapy, CAR T-cell therapeutics also present significant challenges in the individual and time-consuming preparation for patients as well as the potential for severe adverse effects. An emerging approach to overcome these challenges is the use of CAR NK-cell therapeutics.
Dinesh Kundu, MBBS, CEO and co-founder East Ocyon Bio, an India- based biotech start-up, explains, “CAR NK therapies are derived from healthy donor cells, allowing for an off-the-shelf, allogeneic product that can be produced at scale. A single donor batch can yield up to 20 doses currently (and maybe hundreds of doses in the future), significantly reducing the per-dose manufacturing cost. This scalability is particularly beneficial in India and other low- and middle-income countries where the high volume of cancer cases demands rapid and widespread treatment availability. The off-the-shelf nature of CAR NK therapies also minimizes the turnaround time from cell collection to treatment, which is crucial for patients with aggressive cancers.”
Renu Kundu, PhD (left), Director and Co-founder, Dinesh Kundu, MBBS, (right), CEO and Co-founder, East Ocyon Bio
Kundu says CAR NK cells exhibit a superior safety profile compared to CAR T cells. “They present a lower risk of severe adverse effects such as CRS and graft-versus-host disease (GvHD), making them a safer option for a broader patient population.”
The company’s technology engineers NK cells derived from peripheral blood with a CAR that targets PD-L1, a protein frequently overexpressed on tumor cells that aids in immune evasion. Kundu elaborates, “The CAR construct is introduced into NK cells using a baboon pseudotype gamma retroviral vector—a specialized vector that enhances gene transfer efficiency. The baboon envelope pseudotype improves the tropism for NK cells, ensuring robust and stable CAR expression, which is essential for effective tumor targeting.”
Director and co-founder Renu Kundu, PhD, indicates that preclinical studies have already demonstrated significant cytotoxicity against ovarian and other cancer cell lines. “We are progressing toward early-phase clinical trials in collaboration with Indian research hospitals and other partners. Simultaneously, we recognize the importance of staying at the forefront of global innovation. To achieve this, we will continue forging strategic partnerships with top-tier universities and biotech centers in the U.S. and Europe.”
Engineering stealth features
Nikolaus Trede, MD, PhD
Sr. Vice President
Century Therapeutics
“NK cells are potent killers but have limited capacity to expand and persist, which contributes to a predicted safer profile,” observes Nikolaus Trede, MD, PhD, senior vice president and head of clinical development, Century Therapeutics. The company is developing an allogeneic (off-the-shelf), iPSC-derived cell therapy platform.
Trede informs, “The benefit of an ‘off-the-shelf’ approach is the potential to overcome the limitations of first-generation, autologous cell therapies by providing readily available treatment more quickly, reliably, at greater scale, and to a broader patient population without the need of washout of immunosuppressive drugs for apheresis and manufacturing. On the flip side, the inherent challenge of allogeneic cell therapy is the potential for rejection by the host immune system.”
To address this obstacle, the company creates genetically modified NK cells to create “advanced soldiers,” termed iNK. Trede expands, “Our cells are engineered to escape recognition and destruction and thus co-exist with the host immune system. That feat is accomplished by engineering ‘stealth features’ that includes eliminating HLA-I and HLA-II to avoid allo-recognition by T cells coupled with the overexpression of HLA-E to block endogenous NK cells that would be activated by the absence of HLA-I.”
Century is clinically assessing one of the first Allo-Evasion
In Century Therapeutics’ laboratory space at One uCity Square in Philadelphia, PA, scientists are developing allogeneic, iPSC-derived cell therapies with the potential to overcome the limitations of first-generation autologous cell therapies. [David Rosen]
Trede reports, “We have shown that in the presence of a restored immune system, infusions with CNTY-101 have the same persistence profile as infusions given when endogenous T and NK cells are depressed under the influence of lymphodepletion. While these results are encouraging, Century continues to innovate with even more comprehensive ways to suppress endogenous NK cells.”
Reference
- Newman MJ. Invention and characterization of a systemically administered, attenuated and killed bacteria-based multiple immune receptor agonist for anti-tumor immunotherapy. Front Immunol. 2024 Nov 7;15:1462221. doi: 10.3389/fimmu.2024.1462221
The post The Body’s Delta Force: Natural Killer Cells Re-Emerge appeared first on GEN - Genetic Engineering and Biotechnology News.