Stem cell mobilisation and collection in Glasgow including the use of plerixafor

Joy Sinclair Nurse Manager Clinical Apheresis Unit SNBTS, Glasgow

Background on the Clinical Apheresis Service in Glasgow

 Department set up in the early 1990’s  Specifically for apheresis procedures  Performed 1500 procedures 2010- 2011   Peripatetic Service Currently 6 members of nursing staff

Background on the Clinical Apheresis Service in Glasgow

     1100 Therapeutic Plasma Exchange Procedures (TPE)  Around 400 mobile procedures 160 Extra Corporeal Photopheresis (ECP) 20 Red Blood Cell Exchange (RBCX) 175 Peripheral Blood Stem Cell Collection (HPC-A)  150 Autologous  25 Allogeneic Use COBE Spectra and Spectra Optia

Objectives



Timing of mobilisation



Plerixafor



Planned use



Rescue



The Collection



Procedural considerations



COBE Spectra



Spectra Optia

Timing of Mobilisation

       No weekend processing facility In an unusual situation we can collect on a Sunday Chart based on historical departmental data Shared with 50 referring haematologists throughout West of Scotland Encouraged to contact CAU to confirm dates Patient Appointment Biggest challenge - paediatrics

Tuesday

Mechanism of Action – G-CSF

 Haematopoietic stem cells are held in the bone marrow by using the chemokine receptor

CXCR4

to look for/ identify a “homing” signal from the chemokine

SDF1

(Stromal Derived Factor).

 They are also “tethered” to osteoblasts (bone progenitor cells) by cell adhesion proteins such as

VCAM

.

 GCSF stimulates the production of neutrophils in the bone marrow, which in turn increases the number of WBCs in the blood. However, as part of this process the bone marrow can get packed out with neutrophils.  Neutrophils naturally produce protease enzymes including elastase. At high levels these can break down SDF1 (which is a small protein) and therefore

reduce the “homing” signal for stem cells.

Neutrophil proteases can also break down cell adhesion proteins like VCAM and

release stem cells from their normal “tethers”

.

 With the

lack of SDF1

and

breakdown of VCAM

, the stem cells will come out of quiescence in the bone marrow and migrate into the blood giving us the opportunity of collecting them on a cell separator.

Mechanism of Action - Plerixafor

 Plerixafor has a different mechanism of action in that it

directly works at the CXCR4 receptor by blocking it.

The stem cells therefore do not have the ability to detect the presence of SDF1 and will again come out of quiescence and migrate into the blood giving the opportunity to collect them on a cell separator  Evidence at the moment suggests plerixafor works well combined with G-CSF.

Plerixafor - Approval



Scottish Medicines Consortium approval for plerixafor

 Approval of plerixafor by the SMC allows the drug to be prescribed routinely by NHS Scotland for its licensed indications on the advice of an Oncologist or Haematologist  Approved in combination with G-CSF for PBSC mobilisation for Myeloma or lymphoma patients whose cells mobilised poorly  This allows the drug to be used on a remobilisation basis and on an immediate rescue basis

Plerixafor- Planned re-mobilisation

    Wait 4 weeks to allow the patient’s marrow to recover Re-mobilise patient with G-CSF 10 micrograms/kg/day for 4 days & plerixafor on evening of day 4 Apheresis morning of day 5 Repeat G-CSF, plerixafor and apheresis daily until enough cells are collected

Plerixafor - Planned re-mobilisation

     Avoid weekend procedures by planning day 1 G-CSF on a Friday. First dose plerixafor will be due on Monday which will give 4 days available to collect PBSC Plerixafor can be given as an out-patient in the late evening (9.30 pm). Well-motivated patients may safely self-administer.

Timing of collection is important: guidance from Genzyme in plerixafor package insert suggests starting apheresis 11 hours post dose. (Our practice is to start at 9 am, 11-12 hours post dose) Consider large volume apheresis Don’t wait on peripheral CD34+ count

Plerixafor - Planned re-mobilisation

   

Advantages

Timing for apheresis is predictable Successful for most patients with a average of 2 doses of plerixafor Time to organise and plan both for the staff and patient     

Disadvantages

Delay in collecting the cells PBSC on a high WCC so product is more cellular leading to high cryopreservation volumes and more DMSO Theoretical danger of hyperleucocytosis Probably less cost effective than ‘immediate rescue’ use

Plerixafor - Immediate-rescue

      Patient receives mobilising chemotherapy as planned WCC and peripheral CD34 count check on predicted day of mobilisation If neutrophils are recovered but CD34 count low plerixafor can be given that evening G-CSF given at 7am the following morning Apheresis commenced at 9 am GCSF, plerixafor and apheresis repeated daily until patient has enough cells

Plerixafor - Immediate-rescue

     

Advantages

Cost effective. Some patients predicted to mobilise poorly may do OK by conventional means No need for the patient to come back and go through the ‘pre collection process’ again No transplant delay for the patient Fewer plerixafor doses required to achieve transplantable cell dose in our experience (1.4 doses) The collection is usually done on a lower WCC so less cryopreservation issues      

Disadvantages

Plerixafor toxicities maybe higher if added to pre exisiting toxicities of chemo esp. GI toxicities Not as predictable for apheresis scheduling Potential problem with ideal collection time over the weekend Logistics for staff and patients organising process at the last minute (ordering, prescription, late night injection, early morning G-CSF and apheresis) It’s a great deal of information for the patients with little time to digest

Plerixafor - Approved Protocol

   We have an approved protocol for plerixafor use in the West of Scotland This allows re-mobilisation with plerixafor for myeloma and lymphoma patients.

It also allows immediate rescue if the patient meets certain criteria

Plerixafor Criteria for Immediate-Rescue

     Must be a definite date for transplant Must be no more than 1 day before anticipated date of first mobilisation Total WBC on first plerixafor day must be at least 4.0 x 10 9 /l but less than 20 x10 9 /l Peripheral CD34 count must be less than 15 per m l Patient must be infection free There is some published evidence that giving plerixafor in patients with WBC above 20 also works

Plerixafor Collection Considerations

     Change in goal posts now looking for minimum transplant dose (Glasgow 2.5 x 10 6 kg) but higher doses may be possible Consider collecting the patients stem cells 11 hours post plerixafor without waiting for a CD34 count.

Consider a large volume apheresis to work towards achieving transplant dose (3xTBV) Ensure good venous access Consider if second dose of plerixafor required or if G-CSF may be enough

The Collection

   We use both Spectra Optia and Cobe Spectra for collection Cobe Spectra   Data over 5 years 500 procedures Efficiency is 50% (CE2) Spectra Optia  Data over 1 year – 100 procedures  Efficiency is 55% (CE2)

Procedural considerations General

     Consider a large volume apheresis to work towards achieving transplant dose (3xTBV) Consider a high flow procedure to process more cells per minute Remember increasing flow rate will increase AC infusion rate to the patient.

Consider using IV calcium gluconate/chloride Consider increasing AC ratio. This allows you to process faster but with the same AC infusion rate to the patient (max 15:1)

Procedural considerations Cobe Spectra

 

Spectra

- consider increasing the collect flow to 1.1 or 1.2 if WBC count above 40 (calculation tool on CaridianBCT web site)

Spectra

– consider collecting at 3.5 – 5% Hct. This maximises mononuclear cell collection but also will increase RBC and granulocyte contamination

Procedural considerations Spectra Optia



Optia

collects a purer product than Spectra and eliminates problematic high cryopreservation volumes seen with Spectra collections on high WBC count’s.  This is particularly useful for patients mobilised with plerixafor where high WBC levels are likely.

Procedural considerations Spectra Optia

 Optimization guide from CaridianBCT  Set default value of the chamber chase to 4 mls  Aim for 750-1250ml inlet volume processed per chamber  WBC > 20 start or change to a collection preference (CP) of 20  WBC < 10 start or change to a collection preference (CP) of 60  Consider use of inlet Volume control

In summary

      Glasgow annual Autologous HPC-A procedure numbers are between 150 – 200 Until 2008 10-15% failure rate in mobilisation Since 2008 with the introduction of plerixafor we have had a 100% success rate in collecting a transplantable dose Average of 1.5 procedures to collect a transplantable dose (Min 2.5 CD34 x 10 6 , Max 6 CD34 x 10 6 ) Consideration should be given to optimizing the collection tailored to individual situations Spectra Optia is as efficient if not more efficient than Cobe Spectra