Initiation of study has been paused, but may re-start in the future.

This is an open-label Phase II trial to evaluate the efficacy of a hematopoietic cell-based gene therapy for patients with Pyruvate Kinase Deficiency (PKD).

Autologous hematopoietic stem cells from mobilized peripheral blood will be transduced ex vivo (outside the body) with a lentiviral vector carrying a correct copy of the deficient PKLR (Pyruvate Kinase L/R) gene. The corrected stem cells will be infused intravenously back into the patient to correct the hematological manifestations of the disease.

Inclusion Criteria

1. Pyruvate Kinase Deficiency (PKD) diagnosis with a confirmed PK-LR mutation

2. Significant anemia defined as:

   • Hemoglobin (Hb) levels <9.5 g/dL documented during 2 or more assessments in the 12 months prior to screening and either:

     1. at least 6 Red Blood Cell (RBC) transfusion episodes over the 12- month period prior to screening or
     2. at least 3 Red Blood Cell (RBC) transfusion episodes each year for 2 years prior to screening; or

   • Hemoglobin (Hb) levels <8.5 g/dL irrespective of transfusions (documented during 2 or more assessments during the prior 2 years); or

   • Hemoglobin (Hb) levels <10.0 g/dL irrespective of transfusions (documented during 2 or more assessments during the prior 2 years) and the presence of either:

     • Fatigue or energy-related symptoms limiting activities of daily living (The National Cancer Institute Common Terminology Criteria for Adverse Events v 5.0 (NCI CTCAE v5.0 grade 3)); or
     • Fatigue or energy-related symptoms limiting activities of daily living (The National Cancer Institute Common Terminology Criteria for Adverse Events v 5.0 (NCI CTCAE v5.0 grade 2)) not responsive to available medical therapy; or
     • Icterus limiting social interactions, education or work activities and not responsive to available medical therapy;

3. Subject age: age ≥8 years and ≤55 years

4. Prior splenectomy

5. Adequate cardiac, pulmonary, renal and hepatic function, as detailed in relevant exclusion criteria

6. Availability of detailed medical records, including accurate transfusion history and blood count assessments, for the prior 2 years

7. Willing and able to read and correctly understand the patient information sheet and provide consent (or informed assent for minors) regarding study participation, willing and able to comply with all study-related procedures including follow-up visits.

8. Negative serum pregnancy test for female subjects of childbearing potential.

Exclusion Criteria

1. Presence of other known causes of hemolysis (in addition to Pyruvate Kinase Deficiency (PKD)). Patients with concurrent G6PD deficiency diagnosed during pre-study evaluation may be considered for eligibility if in the opinion of the Investigator, the hemolytic anemia is the result of PKD and the Glucose-6-phosphate dehydrogenase (G6PD) deficiency is considered an incidental finding.

2. A venous thromboembolic event (VTE; i.e., pulmonary embolism or deep vein thrombosis) or arteriothromboembolic event (ATE; including unstable angina, myocardial infarction, stroke or transient ischemic attack) during the prior 12 months.

3. Evidence of bridging fibrosis, cirrhosis or active hepatitis on liver biopsy.

   1. Liver biopsy is required when liver iron concentration (LIC) is ≥15 mg/g on T2* magnetic resonance imaging (MRI) of liver.
   2. If a liver biopsy has been performed less than 6 months prior to enrollment, it does not need to be repeated.

4. Cardiac T2* <10 ms by magnetic resonance imaging (MRI) or left ventricular ejection fraction (LVEF) <45% by echocardiogram or multiple gated acquisition scan (MUGA).

5. Any evidence of severe iron overload beyond parameters stipulated in exclusion criteria 3 and 4 that, per Investigator discretion, warrants exclusion.

6. Significant medical conditions including documented HIV (human immunodeficiency virus) infection, active viral hepatitis, poorly controlled hypertension, pulmonary hypertension, cardiac arrhythmia or congestive heart failure; or arteriothromboembolic events (ATEs) (including stroke or myocardial infarction) within the 12 prior months.

7. Active hematologic or solid organ malignancy, not including non-melanoma skin cancer or another carcinoma in situ. Patients with previously resected solid organ malignancies or definitively treated hematologic malignancies may be eligible if there has been no evidence of active malignancy during the prior 3 years.

8. Uncontrolled seizure disorder.

9. Hepatic dysfunction as defined by Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >2.5× the upper limit normal (ULN).

10. Renal dysfunction defined as serum creatinine >upper limit normal (ULN). Patients with creatinine above ULN may be eligible pending documentation of a glomerular filtration rate ≥60 mL/min/1.73m2 as calculated by Modification of Diet in Renal Disease equation (Stevens 2006), or 24-hour urine collection.

11. Pulmonary dysfunction as defined by either:

    1. Need for supplemental oxygen during the prior 2 weeks (in absence of acute infection) OR
    2. Clinically significant pulmonary disease that may impair ability to tolerate study procedures and treatments.

12. Any medical or other contraindication for leukapheresis as determined by the treating Investigator.

13. Any medical or psychiatric condition that in the opinion of the Investigator renders the patient unfit for trial participation or at higher than acceptable risk for participation.

14. Poor functional status evidenced by Karnofsky Index <70 in subjects ≥16 years old and Lansky Play-Performance Scale <70 in subjects <16 years old.

15. Participation in another clinical trial with an investigational drug within 14 days before the informed consent signature. Participation in observational studies is allowed. Patients who are receiving mitapivat in non-investigational settings are eligible provided they discontinue mitapivat at least 90 days prior to the start of mobilization.

16. Pregnant women or women with a positive serum pregnancy test at screening or breast feeding or planning to become pregnant within the next 24 months. Female participants or female partners of male participants not willing to use highly effective contraceptive methods during the complete study period.

17. Previous allogeneic or other hematopoietic stem cell transplant.