Inclusion Criteria for the Study:

• Able to provide written informed consent/assent and comply with the study assessments for the full duration of the study
• Age ≥ 16 years
• Clinically stable, in the opinion of the investigator
• Use of a cuffed tunneled HD catheter
• HD prescribed at a BFR of ≥ 300 mL/min
• Baseline BFR (during the first 30 minutes of HD) of < 300 mL/min (using catheter lines in the customary direction, prior to any reversal of lines) at an arterial pressure of -250 mmHg (or at institutional guidelines for maximum negative arterial pressure, not to exceed 250 mmHg)
• Baseline BFR (during the first 30 minutes of HD) at least 25 mL/min below the prescribed BFR
• Demonstrated BFR of ≥ 300 mL/min (using catheter lines in the customary direction) at an arterial pressure in the range of 0 to -250 mmHg in at least one HD session in the 7 days prior to Visit 1
• Anticipated use of the same catheter for at least four consecutive HD sessions, on the same type and model of HD apparatus
• Able to have fluids infused at the volume necessary to instill study drug into the HD catheter

Exclusion Criteria for the Study:

• HD catheter with sustainable BFR of ≥ 300 mL/min following subject repositioning
• HD catheter inserted < 2 days prior to screening
• Evidence of a mechanical, non-thrombotic cause of HD catheter dysfunction (e.g., kink in the catheter or suture constricting the catheter), or dysfunction caused by known fibrin sheath
• Use of an implantable port
• HD catheter implanted in the subclavian vein
• Anticipated use of catheter for any other type of diagnostic or therapeutic procedure (i.e., other than HD) during the course of the study
• Previously treated in this study or any tenecteplase catheter clearance trial
• Use of any investigational drug or therapy within 28 days prior to screening
• Use of a fibrinolytic agent (e.g. alteplase, tenecteplase, reteplase, or urokinase) within 7 days prior to Visit 1
• Known to be pregnant or lactating at screening
• HD catheter with known or suspected infection
• History of any intracranial hemorrhage, aneurysm, or arteriovenous malformation
• Use of any heparin (unfractionated or low molecular weight) within 24 hours prior to Visit 1, except for heparin used only during HD or for prophylaxis (e.g., heparin lock)
• Use of warfarin within 7 days prior to Visit 1, except for low-dose warfarin used for prophylaxis
• Initiation of or increase in dose of Plavix(R) (clopidogrel bisulfate) within 7 days prior to Visit 1
• Hemoglobin ≥ 13.5 g/dL if on erythropoietin
• Platelet count < 75,000/uL
• At high risk for bleeding events or embolic complications (i.e., recent pulmonary embolus, deep vein thrombosis, endarterectomy, or clinically significant right-to-left shunt) in the opinion of the investigator, or with known condition for which bleeding constitutes a significant hazard
• BFR of < 300 mL/min because of symptomatic hypotension
• Uncontrolled hypertension in the opinion of the investigator (e.g., systolic pressure > 185 mmHg and diastolic pressure > 110 mmHg)
• Known hypersensitivity to tenecteplase or any component of the formulation

Inclusion Criteria for the Retreatment Course:

• Treatment success at Visit 1 or Visit 2
• Clinically stable, in the opinion of the investigator
• Continued use of the same cuffed, tunneled HD catheter (i.e., the catheter the subject had in place during the initial treatment course)
• HD prescribed at a BFR of ≥ 300 mL/min
• RT baseline BFR of < 300 mL/min (using catheter lines in the customary direction, prior to any reversal of lines) at an arterial pressure of -250 mmHg (or at institutional guidelines for maximum negative arterial pressure, not to exceed 250 mmHg)
• RT baseline BFR at least 25 mL/min below the prescribed BFR
• Anticipated use of the same catheter for at least three consecutive HD sessions, on the same type and model of HD apparatus
• Able to have fluids infused at the volume necessary to instill study drug into the HD catheter

Exclusion Criteria for the Retreatment Course:

• HD catheter with sustainable BFR of ≥ 300 mL/min following subject repositioning
• Evidence of a mechanical, non-thrombotic cause of HD catheter dysfunction (e.g., kink in the catheter or suture constricting the catheter), or dysfunction caused by known fibrin sheath
• Anticipated use of catheter for any other type of diagnostic or therapeutic procedure (i.e., other than HD) during the retreatment course of the study
• Use of any investigational drug or therapy other than tenecteplase within 21 days prior to RT Visit 1
• Use of a fibrinolytic agent other than tenecteplase in this study (e.g. alteplase, reteplase, or urokinase) within 7 days prior to RT Visit 1
• Known to be pregnant or lactating at RT Visit 1
• HD catheter with known or suspected infection
• History of any intracranial hemorrhage, aneurysm, or arteriovenous malformation
• Use of any heparin (unfractionated or low molecular weight) within 24 hours prior to RT Visit 1, except for heparin used only during HD or for prophylaxis (e.g., heparin lock)
• Use of warfarin within 7 days prior to RT Visit 1, except for low-dose warfarin used for prophylaxis
• Initiation of or increase in dose of clopidogrel bisulfate within 7 days prior to RT Visit 1
• Known hemoglobin ≥ 13.5 g/dL between initial treatment course and RT Visit 1 if on erythropoietin
• Known platelet count < 75,000/uL between initial treatment course and RT Visit 1
• At high risk for bleeding events or embolic complications (i.e., recent pulmonary embolus, deep vein thrombosis, endarterectomy, or clinically significant right-to-left shunt) in the opinion of the investigator, or with known condition for which bleeding constitutes a significant hazard
• BFR of < 300 mL/min because of symptomatic hypotension
• Uncontrolled hypertension in the opinion of the investigator (e.g., systolic pressure > 185 mmHg and diastolic pressure > 110 mmHg)
• Known hypersensitivity to tenecteplase or any component of the formulation