Virus purification

1. A process for producing a retroviral vector formulation comprising a purification step, a filter-sterilisation step and a concentration step, wherein the filter-sterilisation step is the penultimate step in the production process, wherein the filter-sterilisation step is performed using a sterilising filter with a maximum pore size of 0.2 μm, wherein the concentration step is performed in aseptic conditions, wherein the concentration step is the final step in the process, and wherein concentration of the retroviral vector formulation is performed using an ultrafiltration step; wherein the retroviral vector formulation is suitable for ex vivo administration or for administration to a patient.

2. The process according to claim 1 wherein a preparation comprising retroviral vector is diluted prior to the filter-sterilisation step.

3. A process for producing a bulk vector product comprising the following steps (i) to (vi) in chronological order:

(i) culturing cells that produce retroviral vector;

(ii) harvesting the retroviral vector containing supernatant;

(iii) optionally clarifying the supernatant;

(iv) purifying the retroviral vector to give a retroviral vector preparation;

(v) filter-sterilising the retroviral vector preparation using a sterilising filter with a maximum pore size of 0.22 μm, wherein step (v) is the penultimate step in the process; and

(vi) concentrating the retroviral vector preparation using an ultrafiltration step to produce the bulk vector product, wherein step (vi) is performed under aseptic conditions; and wherein step (vi) is the final step in the process;

wherein the retroviral vector preparation is suitable for ex vivo administration or for administration to a patient.

4. The process according to claim 3 wherein step (iv) is performed using a method or combination of methods selected from chromatography, ultrafiltration/diafiltration, and centrifugation.

5. The process according to claim 3 wherein a nucleic acid degradation step is carried out at any point up to and including step (iv).

6. The process according to claim 3 wherein the purification step (iv) includes one or more buffer exchange steps.

7. The process according to claim 3 wherein step (iii) is performed by filter clarification.

8. The process according to claim 6 wherein the buffer exchange comprises exchange of the ultrafiltration/diafiltration retentate with formulation buffer.

9. The process according to claim 3 wherein the retroviral vector preparation is diluted after purification and prior to filter-sterilisation.

10. The process according to claim 1 or 3 wherein the retroviral vector is a lentiviral vector.

11. The process according to claim 1 or 3 wherein the retroviral vector comprises a nucleotide of interest (NOI).