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Updated June 2026 · ClinicalTrials.gov

RECRUITINGPhase 1 / Phase 2INTERVENTIONAL

Safety and Efficacy of KLS-1 Monotherapy in Malignant Neoplasms

A Phase I/II Open-label Multicenter Dose Escalation and Dose Expansion Study to Evaluate the Safety and Efficacy of KLS-1 as Monotherapy in Patients With Malignant Neoplasms

Safety and Efficacy of KLS-1 Monotherapy in Malignant Neoplasms (NCT06506643) is a Phase 1 / Phase 2 interventional studying CLL and Solid Tumor, Adult, sponsored by Vector Vitale LLC. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

Important: This information is not medical advice. Talk to your doctor about whether a clinical trial is right for you.

About This Trial

The goal of this clinical trial is to test the safety and preliminary efficacy of a new drug, KLS-1, in adults with different types of solid tumors and chronic lymphocytic leukemia (CLL). The main questions it aims to answer are: * To define Dose Limiting Toxicities (DLT) and maximum tolerated dose (MTD) of KLS-1 * To select the recommended Phase II Dose (P2D) of KLS-1 * To determine the single dose and multiple dose PK profile following IV administration of KLS-1 * What is the safest and most effective dose of KLS-1? * Does KLS-1 show anti-tumor activity in patients? * To evaluate preliminary efficacy of KLS-1 in up to 4 cohorts of locally advanced or metastatic solid tumor (malignant melanoma, prostate cancer, pancreatic cancer), or CLL. * To evaluate 12-months progression-free survival (PFS) and duration of response (DOR) follow-up after the last dose of KLS-1 Participants will: * Receive KLS-1 through intravenous (IV) infusions in 21-day cycles. * Be monitored for side effects and improvements in their malignancy. Investigators will compare different doses of KLS-1 in the initial phase to find the best dose for Phase II. Once the P2D is defined, it will be tested in a larger group to see its effects on locally advanced or metastatic solid tumor (malignant melanoma, prostate cancer, pancreatic cancer) and CLL.

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For CLL, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 36 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: Phase I and Phase II - solid tumors cohorts 1. Adult (male or female) aged ≥18 years. 2. Signed willing to sign a consent form prior to any study-specific procedures. 3. Patients who are willing to make themselves available for the duration of the study and are willing to follow study procedures. 4. Have a performance status on the Eastern Cooperative Oncology Group (ECOG) scale of: Phase I - 0 or 1; Phase II - 0-2. 5. Have an estimated life expectancy of ≥12 weeks. 6. Have your organs (liver, kidneys, etc.) are working well enough based on blood tests including: a. Hematologic: - white blood cell count (ANC) at least 1.5 x 109/L - platelet count at least 100 x 109/L - blood count (hemoglobin) at least 90 g/L b. Hepatic: - Albumin ≥30 g/L - Bilirubin ≤1.5 times upper limit of normal (ULN) - ALT and AST ≤2.5 x ULN. If the liver has tumor involvement, AST and ALT ≤5 x ULN are acceptable. c. Renal: - Estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 d. Blood coagulation: - International Normalized Ratio (INR) or activated partial prothrombin time (aPTT) \<1.5 x ULN and \> 0.8 x LLN lower limit of normal (LLN). 7. Have discontinued all chemotherapy, investigational therapy, molecularly targeted therapy, and cancer-related hormonal therapy at least 30 days prior to study enrollment (6 weeks for mitomycin-C or nitrosoureas). 8. Have discontinued biologic therapy and immunotherapy at least 21 days prior to study enrollment. 9. Patients who have had radiation therapy must be fully recovered in the opinion of the investigator prior to enrolling on study. 10. Are recovered or recovering from the acute adverse effects of any chemotherapy, biologic therapy, immunotherapy, molecularly-targeted therapy, cancer-related hormonal therapy, and investigational therapy (≤Grade 1 or baseline), with the exception of alopecia or Grade 2 neuropathy. 11. Have received at least 1 but no more than 4 prior systemic therapies for CLL. ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language
Inclusion Criteria: Phase I and Phase II - solid tumors cohorts 1. Adult (male or female) aged ≥18 years. 2. Signed informed consent prior to any study-specific procedures. 3. Patients who are willing to make themselves available for the duration of the study and are willing to follow study procedures. 4. Have a performance status on the Eastern Cooperative Oncology Group (ECOG) scale of: Phase I - 0 or 1; Phase II - 0-2. 5. Have an estimated life expectancy of ≥12 weeks. 6. Have adequate organ function including: a. Hematologic: * ANC ≥1.5 x 109/L * Platelets ≥100 x 109/L * Hemoglobin ≥90 g/L b. Hepatic: * Albumin ≥30 g/L * Bilirubin ≤1.5 times upper limit of normal (ULN) * ALT and AST ≤2.5 x ULN. If the liver has tumor involvement, AST and ALT ≤5 x ULN are acceptable. c. Renal: * Estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 d. Blood coagulation: * International Normalized Ratio (INR) or activated partial prothrombin time (aPTT) \<1.5 x ULN and \> 0.8 x LLN lower limit of normal (LLN). 7. Have discontinued all chemotherapy, investigational therapy, molecularly targeted therapy, and cancer-related hormonal therapy at least 30 days prior to study enrollment (6 weeks for mitomycin-C or nitrosoureas). 8. Have discontinued biologic therapy and immunotherapy at least 21 days prior to study enrollment. 9. Patients who have had radiation therapy must be fully recovered in the opinion of the investigator prior to enrolling on study. 10. Are recovered or recovering from the acute adverse effects of any chemotherapy, biologic therapy, immunotherapy, molecularly-targeted therapy, cancer-related hormonal therapy, and investigational therapy (≤Grade 1 or baseline), with the exception of alopecia or Grade 2 neuropathy. 11. Have received at least 1 but no more than 4 prior systemic therapies for CLL. 12. Patients who have had surgery must be fully recovered in the opinion of the investigator prior to enrolling on study (but not less than 28 days for major surgery and 14 days for minor surgery). 13. Female patients with reproductive potential must agree to use 2 forms of highly effective contraception during the study and for at least 3 months following the last dose of IMP. Sexually active male patients must use a barrier method of contraception (condom) during the study and for at least 3 months following the last dose of IMP. 14. Females with child-bearing potential must have had a negative pregnancy test result ≤28 days prior to the first dose of IMP, as well as ≤1 day prior to the first dose of IMP. 15. Patients must be, in the judgment of the investigator, appropriate candidates for experimental therapy, and no standard therapy would confer clinical benefit to the patients. 16. Patients must have at least one lesion that is measurable by RECIST v.1.1. Phase I 17. Patients must have histologically proven evidence of any type of metastatic solid tumor (excluding primary brain tumor) that is evaluable and for whom no approved therapy with demonstrated clinical benefit is available or patients who are intolerant or have declined standard therapy. Phase II 18. Patients must have histologically proven evidence of a solid tumor that is locally advanced and/or metastatic and for whom no approved therapy with demonstrated clinical benefit is available or patients who are intolerant or have declined standard therapy as follows: 1. Cutaneous melanoma 2. Prostate cancer 3. Pancreatic cancer Phase II - CLL cohort 1. Adult (male or female) aged ≥18 years. 2. Signed informed consent prior to any study-specific procedures. 3. Patients who are willing to make themselves available for the duration of the study and are willing to follow study procedures. 4. Subjects with confirmed diagnosis of per iwCLL 2008. 5. Documented disease progression that meets at least one of the iwCLL criteria for requiring treatment. 6. Measurable disease defined by either absolute lymphocyte count (ALC ≥ 5 x 109/L) or nodal lesion by computed tomography (CT). 7. Have a performance status on the Eastern Cooperative Oncology Group (ECOG) scale ≤ 2. 8. Have an estimated life expectancy of ≥16 weeks. 9. Have adequate organ function including: a. Adequate hematologic function in the absence of transfusions (within 6 weeks prior to first dose of study medication) and independent of growth factor support for at least 7 days with the exception of pegylated G-CSF which requires at least 14 days, defined as: * WBC ≥3.0 x 109/L * ANC ≥1.0 x 109/L * Platelets ≥50 x 109/L or ≥ 25 × 109/L if thrombocytopenia is related to CLL b. Hepatic: * Albumin ≥30 g/L * Bilirubin ≤2 x ULN. Subjects with known Gilbert's Syndrome or disease-related hemolysis must have a total bilirubin ≤ 3 x ULN * ALT and AST ≤2.5 x ULN. c. Renal: * Estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 d. Blood coagulation: * International Normalized Ratio (INR) or activated partial prothrombin time (aPTT) \<1.5 x ULN and \> 0.8 x LLN. 10. Have discontinued all chemotherapy, immunotherapy, investigational therapy, biologic therapy, molecularly targeted therapy, and cancer-related hormonal therapy at least 30 days prior to study enrollment (6 weeks for mitomycin-C or nitrosoureas). 11. Are recovered or recovering from the acute adverse effects of any chemotherapy, biologic therapy, immunotherapy, molecularly targeted therapy, cancer-related hormonal therapy, and investigational therapy (≤Grade 1 or baseline), with the exception of alopecia or Grade 2 neuropathy. 12. The subject must also agree to pretreatment and on-treatment bone marrow aspirates. 13. Have received at least 1, but not more than 3 prior lines of therapy according to current guidelines. 14. Patients who have had surgery must be fully recovered in the opinion of the investigator prior to enrolling on study (but not less than 28 days for major surgery and 14 days for minor surgery). 15. Female patients with reproductive potential must agree to use 2 forms of highly effective contraception during the study and for at least 3 months following the last dose of IMP. Sexually active male patients must use a barrier method of contraception (condom) during the study and for at least 3 months following the last dose of IMP. 16. Females with child-bearing potential must have had a negative pregnancy test result ≤28 days prior to the first dose of IMP, as well as ≤1 day prior to the first dose of IMP. 17. Patients must be, in the judgment of the investigator, appropriate candidates for experimental therapy, and no standard therapy would confer clinical benefit to the patients. Exclusion Criteria: 1. Have another tumor of another location except basal cell carcinoma. 2. Have a history of organ transplant (e.g., heart, lungs, liver, bone marrow, or kidney). 3. Females who are pregnant or breastfeeding. 4. Have symptomatic human immunodeficiency virus (HIV) infection, known HIV positive test results or have chronic active hepatitis B or C (screening is not required). 5. Positive COVID-19 test or signs of coronavirus infections. 6. Have clinically significant cardiac disease including any of the following: * A history of congenital long QT syndrome, symptomatic bradycardia, ventricular arrhythmia, uncontrolled atrial fibrillation, second- or third-degree heart block, or other conduction abnormality that in the opinion of the investigator would preclude safe participation in this study. * Congestive heart failure (New York Heart Association Class ≥3). * Unstable angina pectoris, acute myocardial infarction, or stroke ≤12 months prior to enrollment. * QTcF prolongation \>450 msec. 7. Currently taking medication known to prolong the QT interval or induce TdP, which cannot be discontinued or substituted. 8. Uncontrolled type 1 or 2 diabetes with high risk of hypoglycemia. 9. Are a family member of the investigator or staff of the study site. 10. Are currently enrolled in another interventional clinical study of an investigational therapy. 11. Hypersensitivity to any components of KLS-1. Additional exclusion criterion for patients enrolled in Phase II to CLL cohort 12. History of Richter's transformation or prolymphocytic leukemia.

Treatments Being Tested

DRUG

Zinc-64 Aspartate

KLS-1 drug substance is Zinc Aspartate enriched with isotope Zinc-64 to 99.2% mass fraction of total Zinc. KLS-1 investigational medicinal product (IMP) is formulated as a solution, containing 25.64 mg of drug substance in 1 ml and inactive ingredients (water for injections, USP, EuPh).

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Medical Centre of Arensia Exploratory Medicine LLC
Kyiv, Ukraine

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT06506643), the sponsor (Vector Vitale LLC), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT06506643 clinical trial studying?

The goal of this clinical trial is to test the safety and preliminary efficacy of a new drug, KLS-1, in adults with different types of solid tumors and chronic lymphocytic leukemia (CLL). The main questions it aims to answer are: * To define Dose Limiting Toxicities (DLT) and maximum tolerated dose (MTD) of KLS-1 * To select the recommended Phase II Dose (P2D) of KLS-1 * To determine the single dose and multiple dose PK profile following IV administration of KLS-1 * What is the safest and most effective dose of KLS-1? * Does KLS-1 show anti-tumor activity in patients? * To evaluate preliminar… The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT06506643?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT06506643?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT06506643. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06506643. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-06-07 · Data from ClinicalTrials.gov.