Nkarta (NKTX) Risk Factors

Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs for relatively low prevalence populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a drug as an orphan drug if it is a drug intended to treat a rare disease or condition, which is generally defined as a patient population of fewer than 200,000 individuals annually in the United States, or a patient population greater than 200,000 in the United States where there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the United States. In the United States, orphan drug designation entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. On December 16, 2021, we announced that the FDA granted orphan drug designation to NKX101 for the treatment of AML. Similarly, in Europe, the European Commission grants orphan drug designation after receiving the opinion of the EMA Committee for Orphan Medicinal Products on an orphan drug designation application. Orphan drug designation is intended to promote the development of drugs that are intended for the diagnosis, prevention or treatment of life-threatening or chronically debilitating conditions affecting not more than 5 in 10,000 persons in Europe and for which no satisfactory method of diagnosis, prevention, or treatment has been authorized (or the product would be a significant benefit to those affected). Additionally, designation is granted for drugs intended for the diagnosis, prevention, or treatment of a life-threatening, seriously debilitating or serious and chronic condition and when, without incentives, it is unlikely that sales of the drug in Europe would be sufficient to justify the necessary investment in developing the drug. In Europe, orphan drug designation entitles a party to a number of incentives, such as protocol assistance and scientific advice specifically for designated orphan medicines, and potential fee reductions depending on the status of the sponsor. Generally, if a drug with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the drug is entitled to a period of marketing exclusivity, which precludes the EMA or the FDA from approving another marketing application for the same drug and indication for that time period, except in limited circumstances ("sameness"). The applicable period is seven years in the United States and ten years in Europe. The European exclusivity period can be reduced to six years if a drug no longer meets the criteria for orphan drug designation or if the drug is sufficiently profitable such that market exclusivity is no longer justified. Even if we obtain orphan drug exclusivity for our product candidates, that exclusivity may not effectively protect those product candidates from competition because different therapies can be approved for the same condition and the same therapies can be approved for different conditions but used off-label. Even after an orphan drug is approved, the FDA can subsequently approve another drug for the same condition if the FDA concludes that the later drug is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care. In addition, a designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. Moreover, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the drug to meet the needs of patients with the rare disease or condition. Orphan drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process. While we may seek orphan drug designation for applicable indications for our product candidates, we may never receive such designations. Even if we do receive such designations, there is no guarantee that we will enjoy the benefits of those designations.

We have concentrated our research and development efforts on utilizing CAR NK cells as an immunotherapy for the treatment of certain diseases, specifically cancers and, most recently, autoimmune diseases. To date, the FDA has approved only a limited number of cell-based therapies for commercialization as treatments for cancer, no cell-based therapies have been approved for commercial use for the treatment of an autoimmune disease, and no natural killer ("NK")-based cell therapy has been approved for commercial use by any regulatory authority. The processes and requirements imposed by the FDA or other applicable regulatory authorities may cause delays and additional costs in obtaining approvals for marketing authorization for our product candidates. Because our CAR NK-cell platform product candidates are novel, and cell-based therapies are relatively new, especially as potential treatments for autoimmune diseases, regulatory agencies may lack precedents for evaluating product candidates like our CAR NK-cell product candidates. As the cell therapy field develops further, the processes and requirements imposed by the regulatory agencies may evolve in a manner that adversely impacts us. The novelty of our product candidates may lengthen the regulatory review process, including the time it takes for the FDA to review our IND applications if and when submitted, increase our development costs and delay or prevent approval and commercialization of our CAR NK-cell platform product candidates. Use of CAR NK-cell therapies may not gain the acceptance of the public or the medical community, especially for the treatment of autoimmune diseases. The patients with autoimmune disease that we will target with NKX019 are typically not at risk of near-term death, even if they may suffer life-threatening symptoms, so the patients will need to deem the benefits of cell therapy to be worth the risk of unknown potential adverse side effects. Additionally, advancing novel immunotherapies creates significant challenges for us, including: - enrolling sufficient numbers of patients in clinical trials;- training a sufficient number of medical personnel on how to properly thaw and administer our cells, especially in any solid tumor trial wherein the cells are given through a procedure by trained medical doctors;- training a sufficient number of medical and clinical laboratory personnel in the proper collection and handling of clinical samples in our clinical trials to enable a sufficient understanding of CAR NK-cell pharmacokinetics and pharmacodynamics for the design of an optimal dosing regimen;- educating medical personnel regarding the potential side-effect profile of our cells and, as the clinical program progresses, on observed side effects with the therapy;- developing a reliable and safe and an effective means of genetically modifying our cells;- manufacturing and cryopreservation our cells on a large scale and in a cost-effective manner;- sourcing starting material suitable for clinical and commercial manufacturing; and - establishing sales and marketing capabilities, as well as developing a manufacturing process and distribution network to support the commercialization of any approved products. We must be able to overcome these challenges in order for us to develop, commercialize and manufacture our product candidates utilizing CAR NK cells.

CAR NK-cell therapy is a relatively new field. To date, no CAR NK-cell therapies have been licensed in the United States or elsewhere to treat cancer, and no cell therapies of any type have been licensed for the treatment of autoimmune diseases. The history of manufacturing CAR NK cells for clinical use is limited. Our understanding of NK-cell biology is continuously expanding and this is particularly true in relation to autoimmune diseases where there is limited clinical data available and where we have no prior experience. If we find that our current manufacturing processes are inadequate, or should we identify opportunities for material improvement, adaptation of process improvements may require significant additional time and resources to complete. As studies utilizing NK-cell biology develop, new information may become available requiring us to change our product candidate. Process improvements or new clinical data might also necessitate new pre-clinical studies and clinical protocols to establish product comparability. If we are unable to show comparability after a process change, further changes to our manufacturing process and/or clinical trials will be required. For example, if sufficient comparability is not shown, we may be required to repeat one or more clinical trials. A requirement to run a new clinical trial or repeat a clinical trial would delay clinical development and commercialization of the relevant product candidate. Prior clinical experience with NK-cell therapy has been predominantly based on cells from haplomatched donors, i.e., at least half of the major Human Leukocyte Antigen ("HLA") types matched between donor and recipient. Our Phase 1 clinical trials, however, are currently evaluating product candidates manufactured from completely unrelated donors (i.e. used "off-the-shelf"). There is a risk that our early clinical results from our Phase 1 clinical trials using off-the-shelf NKX019 and NKX101 may not be reflective of future clinical trial results which may require us to re-evaluate HLA matching. If it becomes apparent through future preclinical testing or clinical trials that such matching is required, the production of NKX019 or our other product candidates as standardized, off-the-shelf products for all patients will not be achievable. Instead, we would need to establish an alternative approach for each of our product candidates to achieve coverage of the addressable patient population. Furthermore, the killer immunoglobulin-like receptor ("KIR") is found on the surface of NK cells and recognizes certain HLA types. If there is a match between certain KIR molecules and the HLA type, KIR acts as a natural inhibitor of NK activity, thereby serving to prevent immune reactions against an individual's own cells. In our Phase 1 clinical trials, the product candidate is administered regardless of specific KIR phenotype. As we continue our clinical trials, we may discover that retaining a KIR mismatch is required to achieve clinically meaningful activity, and we may need to factor KIR mismatch into the donor and product selection process for patients enrolled in our clinical trials. We also continue to analyze for donor characteristics that correlate with clinical activity and we may decide to select for donors to enhance activity of our product candidates in the clinic. In addition, with respect to the development of the deprioritized NKX101 program for the treatment of malignancies, tumors are sometimes able to evade detection by naturally occurring NK cells by shedding the NKG2D ligands found on malignant cells. While NKX101 has been engineered to resist this shedding mechanism, there can be no guarantee that tumor cells will not retain or regain the ability to shed NKG2D ligand completely despite the presence of NKX101, which would give such tumors a degree of resistance against NKX101. If, upon continued development of NKX101, we were to discover that tumors develop a resistance to NKX101 as a result of such NKG2D ligand shedding, we would need to reengineer NKX101 to counteract this effect, or we might decide to change, pause or abandon any future development efforts for NKX101. Any reengineering of our product candidates or change to the processes we use to manufacture our product candidates could require the redesign of our clinical protocols and clinical trials for our product candidates, significant additional time and resources to complete, and the participation of a significant number of additional clinical trial participants and donors, any of which would delay the clinical development of our product candidates and their eventual commercialization.

Clinical trials are expensive, time consuming and subject to substantial uncertainty. Failure can occur at any time during the clinical trial process, due to scientific feasibility, safety, efficacy, changing standards of medical care and other variables. The results from preclinical testing or early clinical trials of a product candidate may not predict the results that will be obtained in later phase clinical trials of the product candidate. We, the FDA, or other applicable regulatory authorities may suspend or terminate clinical trials of a product candidate at any time for various reasons, including, but not limited to, a belief that patients participating in such trials are being exposed to unacceptable health risks or adverse side effects, or other adverse initial experiences or findings. The FDA, or other applicable regulatory authorities may also require us to conduct additional preclinical studies or clinical trials due to negative or inconclusive results or other reasons, fail to approve the raw materials, manufacturing processes or facilities of third-party manufacturers upon which we rely, find deficiencies in the manufacturing processes or facilities upon which we rely, and change their approval policies or regulations or their prior guidance to us during clinical development in a manner rendering our clinical data insufficient for approval. In addition, data collected from clinical trials may not be sufficient to support the submission of a BLA, MAA or other applicable regulatory filings. We cannot guarantee that any clinical trials that we may plan or initiate will be conducted as planned or completed on schedule, if at all. A failure of one or more of our clinical trials could occur at any stage, and any failure could prevent us from obtaining the FDA and other regulatory approvals necessary to commercialize our product candidates. Events that may prevent successful initiation, timely completion, or positive outcomes of our clinical development include, but are not limited to: - delays in obtaining regulatory approval to commence a clinical trial;- delays in reaching agreement on acceptable terms with prospective clinical trial sites or CROs, the terms of which can be subject to extensive negotiation and may vary significantly among different trial sites and CROs, including delays due to administrative hurdles, lack of significant prior experience with cell therapy for autoimmune disease, or competition between cell therapy companies for prospective clinical trial sites and investigators;- our inability to recruit sufficient patients for our clinical trials in a timely manner or at all;- delays in achieving a sufficient number of clinical trial sites or obtaining the required institutional review board ("IRB"), approval at each clinical trial site;- imposition of a temporary or permanent clinical hold by us or by the FDA or other regulatory agencies based on emerging data;- clinical sites deviating from trial protocol or dropping out of a trial;- our inability to obtain long-term follow-up data due to patient drop out or in cases where patients elect to receive post-protocol treatment for their disease before it progresses;- suspension or termination of a clinical trial by the IRB of the institutions in which such trials are being conducted or by the Data Safety Monitoring Board ("DSMB") (where applicable);- delays in sufficiently developing, characterizing, scaling up, optimizing or controlling a manufacturing process suitable for clinical trials, or production delays, shutdowns or setbacks at any of our contract manufacturers;- delays due to additional regulatory, site and clinical trial participant approvals required if a product candidate, especially a product candidate custom manufactured for a specific patient, does not meet the required specifications;- delays in reaching a consensus with regulatory agencies on the design or implementation of our clinical trials;- changes in regulatory requirements or guidance that may require us to amend or submit new clinical protocols, or such requirements may not be as we anticipate;- changes in the standard of care or treatment landscape on which a clinical development plan was based, which may require new or additional trials;- insufficient quantities or inadequate quality of our product candidates or other materials necessary to conduct preclinical studies or clinical trials of our product candidates, including potential limitations to the availability of agents such as fludarabine ("Flu"), cyclophosphamide ("Cy"), or other agents administered to patients prior to treatment or in combination with our product candidates or delays in the manufacturing of product candidates due to scale up or improvements to our manufacturing process;- clinical trials of our product candidates producing negative or inconclusive results, which may result in our deciding, or regulators requiring us, to conduct additional clinical trials or abandon product development programs;- failure of enrolled patients in foreign countries to adhere to clinical protocol as a result of differences in healthcare services or cultural customs, or additional administrative burdens associated with foreign regulatory schemes; or - failure of ourselves or any third-party manufacturers, contractors or suppliers to comply with regulatory requirements, maintain adequate quality controls, or be able to provide sufficient product supply to conduct and complete preclinical studies or clinical trials of our product candidates. For example, after initially studying NKX019 and NKX101 in Phase 1 clinical trials for hematologic malignancies, we deprioritized development of the product candidates for the treatment of hematologic malignancies to focus our research and development activities on NKX019 for the treatment autoimmune disease. Following an interim evaluation of response data in our NKX101 clinical trial for the treatment of relapsed or refractory acute myeloid leukemia ("r/r AML") or higher risk myelodysplastic syndromes ("MDS"), we decided to deprioritize our NKX101 program. In November 2024, we announced new clinical data from our NKX019 clinical trial in B-cell malignancies. The data came from a cohort of heavily pretreated patients with large B-cell lymphoma ("LBCL") whose disease had already progressed following treatment with a CD19 CAR T cell therapy. Based on these data and the highly competitive landscape for the treatment of B-cell malignancies, we have deprioritized the clinical development of NKX019 for the treatment of B-cell malignancies. We do not plan to enroll further patients in our clinical trials for hematologic malignancies, and we cannot guarantee that we will pursue any further development of NKX101 or NKX019 for the treatment of hematologic malignancies in the near future or at all. Disruptions caused by or related to pandemics, epidemics, or outbreaks of infectious disease, including future outbreaks of COVID-19 variants, may increase the likelihood that we encounter such difficulties or delays in initiating, enrolling, conducting or completing our planned and ongoing preclinical studies and clinical trials, as applicable. For example, we periodically interact with health authorities such as the FDA to obtain advice, or reach consensus, on our ongoing clinical trials, product development, and manufacturing activities. If these health authorities need to prioritize efforts related to a pandemic, epidemic, or outbreak of infectious disease, including future outbreaks of COVID-19 variants, then we may experience delays in obtaining periodic advice which may affect our ability to move our clinical programs forward into the next phase of development. Moreover, principal investigators for our clinical trials may serve as scientific advisors or consultants to us from time to time and receive compensation in connection with such services. Under certain circumstances, we may be required to report some of these relationships to the FDA or comparable foreign regulatory authorities. The FDA or comparable foreign regulatory authority may conclude that a financial relationship between us and a principal investigator has created a conflict of interest or otherwise affected the interpretation of the trial. The FDA or comparable foreign regulatory authority may therefore question the integrity of the data generated at the applicable clinical trial site and the utility of the clinical trial itself may be jeopardized. This could result in a delay in approval, refusal to accept or rejection, of our marketing applications by the FDA or comparable foreign regulatory authority, as the case may be, and may ultimately lead to the denial of marketing approval of our product candidates. We may, from time to time, such as for our NKX019 clinical trial for the treatment of LN (Ntrust-1), establish partnerships in relation to our clinical trials, receiving advisory services and other support from third parties. For example, we have partnered with Lupus Therapeutics, the clinical research affiliate of the Lupus Research Alliance, to accelerate development of NKX019 through select sites of the Lupus Clinical Investigators Network ("LuCIN"). Although we believe that these partnerships will enable us to accelerate the development of our product candidates and clinical trials, we cannot guarantee that such collaborations will be successful and, in the event they are not, we may lose our competitive advantage and/or incur additional costs. As regulatory expectations regarding the genome editing of cellular therapies continue to evolve with data emerging on chromosomal abnormalities from CAR T therapies or other sources, our pipeline programs that involve gene-edited cells, including an allogeneic, off-the-shelf CAR NK-cell product candidate targeting the CD70 tumor antigen ("NKX070") and an allogeneic, off-the-shelf product candidate that comprises both engineered NK cells and engineered T cells ("NK+T"), on which we are collaborating with CRISPR, could be impacted. For example, the FDA may require additional or new release assays for manufactured lots of any product candidates that have been gene edited, which, as a result, could slow development of our gene-edited product candidates and increase expenses. In addition, the FDA's and other regulatory authorities' policies with respect to clinical trials may change and additional government regulations may be enacted. For example, passed in December 2022, the Food and Drug Omnibus Reform Act ("FDORA") requires sponsors to develop and submit a diversity action plan for each Phase 3 clinical trial or any other "pivotal study" of a new drug or biological product. These plans are meant to encourage the enrollment of more diverse patient populations in late-stage clinical trials of FDA-regulated products. Specifically, actions plans must include the sponsor's goals for enrollment, the underlying rationale for those goals and an explanation of how the sponsor intends to meet them. In addition to these requirements, the legislation directs the FDA to issue new guidance on diversity action plans. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies governing clinical trials, our development plans may be impacted. If we experience delays in the initiation, enrollment, or completion of any preclinical study or clinical trial of our product candidates, or if any preclinical studies or clinical trials of our product candidates are canceled, the commercial prospects of our product candidates may be materially adversely affected, and our ability to generate product revenues from any of these product candidates will be delayed or not realized at all. In addition, any delays in completing our clinical trials may increase our costs and slow down our product candidate development and approval process.

We cannot guarantee that NKX019 or any of our other product candidates, will be safe and effective, or will be approved for commercialization, on a timely basis or at all. Although certain of our employees have prior experience with clinical trials, regulatory approvals, and cGMP manufacturing, we have not previously completed any clinical trials or submitted a BLA to the FDA, or similar regulatory approval filings to comparable foreign authorities, for any product candidate, and we cannot be certain that NKX019 or any of our other product candidates will be successful in clinical trials or receive regulatory approval. In particular, we have limited prior experience in developing treatments for autoimmune diseases and our resources and processes have historically been focused on the development of NK-cell therapies for cancer. The FDA, and other comparable global regulatory authorities can delay, limit or deny approval of a product candidate for many reasons. For further details about such reasons, see "-Clinical development involves a lengthy and expensive process with an uncertain outcome, and we may encounter substantial delays due to a variety of reasons outside our control." Any delay in obtaining, or inability to obtain, applicable regulatory approval will delay or harm our ability to successfully commercialize NKX019 or any of our other product candidates, especially and could materially adversely affect our business, financial condition, results of operations and growth prospects. NKX019 is in Phase I clinical development and subject to the risks inherent in drug development. In October 2023, we announced that we had received clearance of an Investigational New Drug ("IND") application by the FDA to evaluate NKX019 for the treatment of LN, and in June 2024, we announced we had received clearance of an IND by the FDA to evaluate NKX019 for the treatment of scleroderma, myositis, and AAV. Ntrust-1 is our multi-center, open-label, dose-escalation Phase 1 clinical trial that evaluates the safety and clinical activity of NKX019 in humans with refractory LN, and Ntrust-2 is our planned multi-center, open-label, dose-escalation Phase 1 clinical trial that will evaluate the safety and clinical activity of NKX019 in humans with scleroderma, myositis, and AAV. In both Ntrust-1 and Ntrust-2, Cy will be used as the lymphodepleting conditioning ("LD") prior to administration of NKX019. There are no cell therapies licensed to date in the United States or elsewhere to treat autoimmune diseases and we have no prior experience in developing treatments for autoimmune diseases. We cannot guarantee that our development of NKX019 for the treatment of LN, scleroderma, myositis, or AAV will be successful. We may also choose to develop NKX019 for additional autoimmune or other indications, but we may not be able to advance NKX019 through the development process for any of these additional indications. Even if we receive regulatory approval to market NKX019 for the treatment of LN, scleroderma, myositis, AAV, or any additional indications, NKX019 for any of these indications may not be successfully commercialized, widely accepted in the marketplace or more effective than other commercially available alternatives. If we are unable to successfully develop and commercialize NKX019 for LN, scleroderma, myositis, AAV, or these additional autoimmune indications, our commercial opportunity will be limited, and our business, financial condition and growth prospects will be materially adversely affected. NKX019 is also being studied in a multi-center Phase 1 clinical trial for the treatment of a variety of B-cell malignancies, which evaluates the safety, pharmacology, and preliminary anti-tumor activity of NKX019. In November 2024, we announced new clinical data from a cohort of heavily pretreated patients with LBCL whose disease had already progressed following treatment with a CD19 CAR T cell therapy. Based on these data and the highly competitive landscape for treatments of B-cell malignancies, We have decided to focus our research and development activities on autoimmune disease and plan for no further investment in the clinical development of NKX019 for the treatment of B-cell malignancies. Due to the commercial availability of multiple therapeutic agents that target CD19, as well as others that are in various stages of development, we have previously had significant difficulty, and may continue to have significant difficulty, enrolling patients. If our ongoing Phase 1 or later clinical trials of NKX019 encounter safety, efficacy, manufacturing problems, enrollment issues, development delays, regulatory issues, or other problems, our development plans for NKX019 could be significantly impaired, which could materially adversely affect our business, financial condition, results of operations and growth prospects. NKX101, our deprioritized clinical-stage product candidate, is also subject to the risks inherent in drug development. NKX101 has been studied in a Phase 1 clinical trial for the treatment of blood cancers including r/r AML or MDS. Following an interim evaluation of the clinical response data, we decided to deprioritize the clinical development of NKX101. Further enrollment in the trial has been closed. We do not plan to pursue any further development of NKX101 without first evaluating our options for the trial design, dosing regimen, and manufacturing process for the program. We cannot guarantee that we will pursue any further development of NKX101 in the near future or at all. Even if we do decide in the future to further develop NKX101 for the treatment of r/r AML or MDS, we may not be successful in doing so. If clinical development of NKX101 is restarted in the future and the Phase 1 or clinical trials of NKX101 for the treatment of AML or MDS encounter concerning safety signals, efficacy concerns, manufacturing problems, enrollment issues, development delays, regulatory issues, or other problems, our development plans for NKX101 could be significantly impaired, which could materially adversely affect our business, financial condition, results of operations and growth prospects. If we restart development of NKX101 at a later point and are able to obtain clinical proof-of-concept from our NKX101 Phase 1 trial for blood cancers including r/r AML and MDS, we may also develop NKX101 for additional indications. We may not be able to advance any of these indications through the development process. The potential development of NKX101 for treating solid tumors, for example, would be subject to a number of risks including a hostile tumor microenvironment and trafficking to tumor site. The development of treatments to treat solid tumors often requires larger and more expensive clinical trials than for treating blood cancers. Even if we receive regulatory approval to market NKX101 for the treatment of any of these additional indications, any such additional indications may not be successfully commercialized, widely accepted in the marketplace or more effective than other commercially available alternatives. If we are unable to successfully develop and commercialize NKX101 for these additional indications, our commercial opportunity may be limited. Furthermore, because NKX019 and NKX101 are our most advanced product candidates, and because our other product candidates are based on similar technology, if our current clinical trials of NKX019 or any future clinical trials of NKX019 or NKX101 experience any of the foregoing issues, our development plans for our other product candidates in our pipeline could also be significantly impaired, which could materially adversely affect our business, financial condition, results of operations and growth prospects. We may develop our product candidates as monotherapy or potentially as combination therapy with one or more currently approved therapies. Even if any product candidate we develop were to receive marketing approval or be commercialized for use in combination with other existing therapies, we would continue to be subject to the risks that the FDA or similar regulatory authorities outside of the United States could revoke approval of the combination therapy used with our product candidate or that safety, efficacy, manufacturing or supply issues could arise with these existing therapies. This could result in our own products being removed from the market or being less successful commercially. We may also evaluate our product candidates in combination with one or more other therapies that have not yet been approved for marketing by the FDA or similar regulatory authorities outside of the United States. If the FDA or similar regulatory authorities outside of the United States do not approve these other drugs or revoke their approval of, or if safety, efficacy, manufacturing, or supply issues arise with, the drugs we choose to evaluate in combination with any product candidate we develop, we may be unable to obtain approval of or market our product candidates.

Although we believe that our allogeneic CD19-targeting CAR NK-cell product candidate NKX019 may have disease-modifying potential in autoimmune disease, such as LN, the use of CD19-targeted CAR cell therapies, and, in particular, allogeneic CD19 CAR NK-cell therapies, represents a novel approach for the treatment of autoimmune disease, and is supported by limited clinical data. To date, no cell therapies have been approved by the FDA for the treatment of autoimmune disease. We cannot guarantee that Ntrust-1, our clinical trial for NKX019 in LN, Ntrust-2, our planned clinical trial for NKX019 in scleroderma, myositis, and AAV, or any other future clinical development of NKX019 for the treatment of autoimmune diseases will be successful. Our belief that NKX019 may be effective as a treatment for autoimmune disease is based largely on our understanding of the mechanism behind the positive clinical data reported by certain academic groups for the use of a CD19 CAR T-cell therapy in a limited number of patients with autoimmune disease, as well as on our own in vitro studies showing that NKX019 can kill B-cells in peripheral blood mononuclear cells ("PBMCs") obtained from patients with autoimmune diseases and observations regarding the effect of NKX019 on B cells from our ongoing NKX019 Phase 1 clinical trial in patients with non-Hodgkin lymphoma ("NHL"). We have made certain assumptions regarding the mechanism of action responsible for the preliminary efficacy shown in the reported studies and how that mechanism of action and our own in vitro data and data from our NKX019 trial in NHL will translate to the response of patients with autoimmune diseases, such as LN, to NKX019, which may or may not be correct. We plan to use Cy alone as the LD in our current, planned and future NKX019 clinical trials for the treatment of autoimmune disease, but there is a risk that Cy alone will not be effective as LD prior to NKX019 in patients with autoimmune disease. We cannot know with any certainty whether NKX019 will be effective against LN, other forms of systemic lupus erythematosus ("SLE") or any other autoimmune disease, or whether NKX019 will be competitive as a treatment for such indications against CD19 CAR T-cell therapies. We also face competition from a large number of cell therapy companies who are also advancing development programs in autoimmune diseases, which may impact our ability to successfully develop and commercialize NKX019. For instance, competition among cell therapy companies for clinical trial sites, investigators, and/or patients for autoimmune clinical trials, may cause delays in the initiation of clinical trials sites and enrollment of patients in our clinical trials. For further details about such reasons, see "-Enrollment and retention of patients in clinical trials is an expensive and time-consuming process and could be delayed, made more difficult or rendered impossible by multiple factors outside our control" and "-If we fail to compete effectively with academic institutions and other biopharmaceutical companies that develop similar or alternatives to cellular immunotherapy product candidates, our business will be materially adversely affected." The competition for clinical trial sites, investigators or patients may also lead to increased development costs. If NKX019 is shown to not be sufficiently effective against LN, scleroderma, myositis, AAV, or other autoimmune diseases in clinical trials, we experience delays in our ability to advance NKX019 through clinical development for LN, scleroderma, myositis, AAV, or other autoimmune diseases, or we are unable to successfully compete against other companies in the development and commercialization of NKX019, the commercial prospects of NKX019, as well as our business, financial condition and growth prospects, would be materially adversely affected.

Identifying and qualifying patients to participate in our clinical trials is critical to our success. Clinical trials of a new product candidate require the enrollment of a sufficient number of patients, including patients who are suffering from the disease that the product candidate is intended to treat and who meet other eligibility criteria. The rates of patient enrollment, a significant component in the timing of clinical trials, are affected by many factors, including: - our ability to open clinical trial sites;- the size and nature of the patient population;- the design and eligibility criteria of the clinical trial;- the proximity of patients to clinical sites;- the patient referral practices of physicians, including as a result of their assessment of the clinical trial parameters;- changing medical practice patterns or guidelines related to the indications we are investigating;- competing clinical trials or approved therapies which present an attractive alternative to patients and their physicians;- perceived risks and benefits of the product candidate under study, including as a result of adverse effects observed in similar or competing therapies;- our ability to obtain and maintain patient consents due to various reasons;- the risk that enrolled patients will drop out or die before completion of the trial;- patients failing to complete a clinical trial or returning for post-treatment follow-up;- our ability to manufacture the requisite supply of our product candidates for our clinical trials; and - any failure or any delay by us or by our clinical sites to obtain sufficient quantities of components and supplies necessary for the conduct of our clinical trials, including any inability to obtain agents such as Cy, Flu, or other agents administered to patients prior to treatment or in combination with our product candidates. We need to compete with many ongoing clinical trials and approved therapies to recruit patients into our clinical trials. Our clinical trials may also compete with other clinical trials of product candidates that are in a similar cellular immunotherapy area as our product candidates, and this competition could reduce the number and types of patients available to us, because some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. For example, due to the commercial availability of multiple therapeutic agents that target CD19 for the treatment of cancer, as well as others that are in various stages of development, we have had significant difficulty in our Phase 1 NKX019 clinical trial for the treatment of B-cell malignancies and may continue to have significant difficulty in our current or future NKX019 clinical trials for certain indications, enrolling patients who have not previously been exposed to a CD19-directed cellular therapy. Additionally, for our ongoing NKX019 clinical trial for the treatment of LN, our planned NKX019 clinical trial for the treatment of additional autoimmune indications, and any future NKX019 clinical trials of ours for the treatment of other autoimmune diseases, the number of qualified clinical investigators is limited, so we may conduct some of our clinical trials at the same clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at such clinical trial site. A number of cell therapy companies have announced initiation of plans for clinical trials for the treatment of LN and/or other autoimmune diseases, which has resulted in and/or may increase competition in the future for investigators and/or patients for our NKX019 clinical trial for the treatment of LN, our planned NKX019 clinical trial for the treatment of additional autoimmune indications, and any other NKX019 clinical trials that we may initiate in the future for the treatment of other autoimmune diseases. Furthermore, we intend to use Cy as the LD prior to treatment with NKX019 in our NKX019 clinical trial for the treatment of LN and our planned NKX019 clinical trial for the treatment of additional autoimmune indications. If this is ineffective or we decide to change the protocol to use a combination of Flu and Cy, as the LD, physicians may choose to refer patients to other clinical trials conducted by one of our competitors. If we are unable to enroll a sufficient number of patients in our clinical trials in a timely manner, our completion of clinical trials may be delayed or may not be achieved, which would prevent us from further developing or commercializing our product candidates in certain patient subpopulations or at all. The clinical development of our product candidates depends on our ability to manufacture and provide the requisite supply of our product candidates for our clinical trials. Any failure or delays by us to manufacture and provide our product candidates in sufficient quantity and quality for the conduct of our clinical trials, may delay our ability to enroll and treat patients in, or complete, our current or future clinical trials of our product candidates on time, if at all. For further details regarding risks related to the manufacture of our product candidates, see "Risks Related to Manufacturing" below, including "-Our manufacturing process is novel and complex, and we may encounter difficulties in production, or difficulties with internal manufacturing, which would delay or prevent our ability to provide a sufficient supply of our product candidates for clinical trials or our products for patients, if approved." The clinical development of our product candidates also depends on the availability of a sufficient supply of certain other materials and agents used in our clinical trials. For example, certain of our clinical trial protocols require the use of Flu and/or Cy, agents which are routinely used in oncology studies, and which we use in certain of our clinical trial protocols to condition patients for treatment with our product candidates. Further, we may develop certain of our product candidates as a combination therapy with other therapies, which would require the availability and use of those therapeutic agents in certain of our clinical trial protocols. Any failure or delays by us or by our clinical sites to obtain sufficient quantities of our product candidates and other agents necessary for the conduct of our clinical trials, may delay our ability to enroll and treat patients in, or complete, our current or future clinical trials of our product candidates on time, if at all. If we are unable to enroll a sufficient number of patients in our clinical trials in a timely manner, our completion of clinical trials may be delayed or may not be achieved, which would prevent us from further developing or commercializing our product candidates.

In order to obtain FDA or other regulatory authority approval to market a new biological product we must demonstrate safety, purity, potency and efficacy in humans. To meet these requirements, we will have to conduct adequate and well-controlled clinical trials. Before we can commence clinical trials for a product candidate, we must complete extensive preclinical testing and studies that support our planned INDs in the United States. Other than NKX019 and NKX101, all of our programs, including NKX070, are in preclinical development. We cannot be certain of the timely completion or outcome of our preclinical testing and studies and cannot predict if the FDA will accept our proposed clinical programs or if the outcome of our preclinical testing and studies will ultimately support the further development of our programs. As a result, we cannot be sure that we will be able to submit INDs or similar applications for our preclinical programs on the timelines we expect, if at all, and we cannot be sure that submission of INDs or similar applications will result in the FDA or other regulatory authorities allowing clinical trials to begin. Conducting preclinical testing is a lengthy, time-consuming and expensive process. The length of time may vary substantially according to the type, complexity and novelty of the program, and often can be several years or more per program. Any delays in preclinical testing and studies conducted by us or potential future partners may cause us to incur additional operating expenses. The commencement and rate of completion of preclinical studies and clinical trials for a product candidate may be delayed by many factors, including, for example: - inability to generate sufficient preclinical or other in vivo or in vitro data to support the initiation of clinical trials;- delays in reaching a consensus with regulatory agencies on acceptable clinical trial design or manufacturing process; and - the FDA not allowing us to rely on previous findings of safety and efficacy for other similar but approved products and published scientific literature. Moreover, because standards for pre-clinical assessment are evolving and may change rapidly, even if we reach an agreement with the FDA on a pre-IND proposal, the FDA may not accept the IND submission as presented, in which case patient enrollment would be placed on partial or complete hold and treatment of enrolled patients could be discontinued while the product candidate is re-evaluated. Even if clinical trials do begin for our preclinical programs, our clinical trials or development efforts may not be successful.

The results of preclinical studies may not be predictive of the results of clinical trials, and the results of any early-stage clinical trials we commence may not be predictive of the results of the later-stage clinical trials. For example, preclinical models as applied to cell therapy in oncology do not adequately represent the clinical setting, and thus cannot predict clinical activity nor all potential risks, and may not provide adequate guidance as to appropriate dose or administration regimen of a given therapy. From time to time, we may publicly disclose preliminary or "topline" data from our clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular trial, including as patient enrollment continues and more data on existing patients becomes available. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the topline results that we report may differ from, and may not be indicative of, future results of the same clinical trials, or different conclusions or considerations may qualify such topline results once additional data have been received and fully evaluated. For example, the preliminary results from the three dose expansion cohorts we announced opening in December 2022 as part of our Phase 1 NKX019 clinical trial for the treatment of B-cell malignancies did not meet expectations. In November 2024, we announced new clinical data from a cohort with a new, condensed dosing schedule. Based on these data and the highly competitive landscape for treatments of B-cell malignancies, we have decided to refocus our research and development activities on autoimmune disease and deprioritized further development of NKX019 for the treatment of B-cell malignancies. Also, an interim evaluation of the data from the most recent dose-expansion cohort of our NKX101 Phase 1 clinical trial indicated that the aggregate clinical response rate for the 20 patients in the cohort was meaningfully lower than it had been for the first six patients in the cohort. As a result, we have now deprioritized further development of NKX101. Topline data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, topline data should be viewed with caution until the final data are available and negative differences between preliminary or interim data and final data could materially adversely affect the prospects of any product candidate that is impacted by such data updates. Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product and the value of our company in general. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is typically a summary of extensive information, and you or others may not agree with what we determine is the material or otherwise appropriate information to include in our disclosure, and any information we determine not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, activities or otherwise regarding a particular product, product candidate or our business. If the topline data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and commercialize, our product candidates may be harmed.

Undesirable side effects that may be caused by our product candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label than anticipated or the delay or denial of regulatory approval by the FDA or comparable foreign regulatory authorities. Results of our clinical trials could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics. Updated data from the dose-escalation portion of our NKX019 Phase 1 clinical trial in B-cell malignancies were reported in December 2022, and updated interim data from our NKX101 Phase 1 clinical trial were reported in June 2023. The most common higher-grade (Grade =3) adverse events in the interim data reported for patients in the NKX019 Phase 1 clinical trial for B-cell malignancies were myelosuppression, which is common in the treated patient population after LD. In the dose-escalation phase of the NKX019 Phase 1 clinical trial, certain patients experienced adverse events including transient fevers and infusion-related reactions. Three patients in the NKX019 dose-escalation study were assessed to have cytokine release syndrome ("CRS"), despite the rapid onset and rapid resolution, not consistent with previously described presentations of CRS with CAR T-cell therapies. The most common higher-grade (Grade =3) adverse events in the interim data reported in June 2023 for patients with r/r AML in the NKX101 Phase 1 clinical trial were myelosuppression – a condition resulting in fewer red blood cells, white blood cells and platelets, as well as infections such as sepsis and pneumonia, occasionally requiring supplementary oxygen, which are common in the treated patient population after LD. The interim data from the NKX101 clinical trial indicated that adverse events experienced by certain patients with r/r AML included infusion reactions, CRS, and one case of immune effector cell-associated neurotoxicity (in each case, =grade 2). A more recent review of the data from additional patients enrolled in a dose-expansion cohort in our NKX101 clinical trial has indicated that the safety profile of NKX101 is consistent with the data reported in June 2023. While the interim data reported to date from our NKX019 and NKX101 Phase 1 clinical trials indicate that NK cell-based therapies may be better-tolerated as compared to T-cell-based therapies due to biologic differences between these cell types, there can be no assurance that patients will not experience CRS, neurotoxicity, Graft-versus-host disease ("GvHD"), or other serious adverse events associated with our specific product candidates NKX019 and NKX101. For instance, NKX101 targets NKG2D ligands, which is not yet a well-characterized modality. NKG2D targets multiple ligands, and the extent and impact of ligand expression is currently not fully characterized. For example, there are risks that ligands may be expressed on either known or an as-yet-underappreciated population of healthy cells. Therefore, such cells may also be targeted by NKX101 and lead to adverse events of unknown frequency and severity as well as potentially decreased efficacy. Such adverse events may cause delays in completion of our clinical programs. Furthermore, in some instances, the diseases we may be seeking to treat may be less serious than the later stage cancers traditionally being treated with cell therapies or other immunotherapy products. Therefore, we believe the FDA and other regulatory authorities likely will apply a different benefit-risk threshold such that any potential harmful side effects may outweigh the benefits of our product candidates and require us to cease clinical trials or deny approval of our product candidates. We believe tolerance for adverse events in the autoimmune patient populations being pursued with cell-based therapies, such as in the LN patients in our NKX019 clinical trial, will be lower than it is in oncology, and the risks of negative impact from these toxicities may therefore be higher for our autoimmune programs than for our oncology programs or the oncology programs of others. If unacceptable side effects arise in the development of our product candidates such that there is no longer a positive benefit-risk profile, we, the FDA, the IRBs at the institutions in which our trials are conducted, or the DSMB could suspend or terminate our clinical trials or the FDA or comparable foreign regulatory authorities could order us to cease clinical trials or deny approval of our product candidates for any or all targeted indications. Treatment-related side effects could also affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff, and inadequate training in recognizing or managing the potential side effects of our product candidates could result in patient injury or death.

In some instances, our product candidates may be evaluated in ISTs conducted by certain clinical investigators who are our collaborators. In addition to supplying product candidate for such trials, we may also provide financial support. In July 2024, we announced that researchers at Columbia University Irving Medical Center ("CUIMC") initiated an IST of NKX019 in patients with SLE, and in November 2024, we announced that the first patient had been dosed in the IST. Although ISTs may provide valuable insights, they also pose regulatory and operational challenges that could impact our ability to bring our product candidates to market. We have limited or no control over the design, administration, and timing of the ISTs and will have no control over the submission or approval of any IND or foreign equivalent required to conduct these trials. We rely on the investigators and physicians to ensure their compliance with clinical and regulatory requirements when using our product candidates for these trials. Their failure to comply could expose us to liability. The ISTs could, depending on the actions of the investigators and other third parties involved in the ISTs, jeopardize the validity of the clinical data generated, identify significant concerns with respect to our product candidates that could impact our findings or clinical trials, and adversely affect our ability to obtain marketing approval from the FDA or other applicable regulatory authorities. To the extent the results of any of these ISTs are inconsistent with, or different from, the results of our current or future company-sponsored trials or raise concerns regarding our product candidates, the FDA or a foreign regulatory authority may question the results of our company-sponsored trials or subject such results to greater scrutiny than it otherwise would. In these circumstances, the FDA or such foreign regulatory authorities may require us to obtain and submit additional clinical data, which could delay clinical development or marketing approval of our product candidates. In addition, while ISTs could be useful to inform our own clinical development efforts or provide other valuable insights, there is no guarantee that we will be able to use the data from these trials to form the basis for regulatory approval of our product candidates. Moreover, the patient population in such trials is at risk for serious adverse events. If these events are attributed to our product candidates, it could negatively impact their safety profile, leading to delays or failure in obtaining regulatory approval or successfully commercializing our drug candidates. Additionally, our supply capabilities may limit patient enrollment in these trials. We may need to restructure or pause supply to enroll sufficient patients in our company sponsored trials, potentially leading to adverse publicity or other disruptions.