8/27- Tx of Hematologic Malignancies/HSC Transplantation Flashcards
(46 cards)
What are the treatment phases of acute leukemia?
Induction:
- “Remission induction” with standard chemo
Consolidation/Intensification: Elimination of residual disease
- Standard chemo
- (High dose) chemo/HSC transplant
Maintenance: Prevention of recurrence
- Low dose standard chemo
**So no such thing as urgent HSC transplant; it’s not 1st step/1st line
What is the rationale for HSCT/principle behind it?
Replace defective marrow with normal marrow
Allow dose intensification of chemotherapy
- Kill residual tumor cells
- Rescue hematopoiesis with normal cells
Induce graft vs. tumor effect
What are the types of donors/transplants?
- Autologous (self)
- Syngeneic (identical twin)
- Allogeneic
What is the point of autologous transplants?
Able to sustain high dose chemo
Fill out
What is an allogeneic transplant (sources)?
- Matched sibling
- Closely matched unrelated donor (fully matched, >/= 1 mismatches)
- Haploidentical family member
What are sources of HSCs?
- Bone marrow
- Peripheral blood
- Cord blood
The graft includes stem cells and what else?
T cells?????
What is the process of bone marrow harvest?
- BM is harvested and pooled by passing through series of filters and into collection bag
- Filters remove bone fragments and platelet clots
How are peripheral blood stem cells collected? Process?
Apheresis
- Peripheral blood removed form donor
- As it passes through centrifuge channel a mononuclear rich portion of the blood is collected while the remainder of the plasma and RBCs are returned to the donor
PBSC versus bone marrow
- Priming required
- Number of collections
- Anesthesia required
How is cord blood collected/stored?
- Taken at birth/delivery
- HSCs may be infused fresh or cryopreserved (cord blood itself is cryopreserved?)
What are indications/uses for autologous SC transplantation?
Malignant diseases:
- Myeloma
- Non-Hodgkin Lymphoma
- Hodgkin lymphoma
- Acute leukemia
(Autoimmune diseases- reboots the system)
What are indications/current uses for allogeneic SC transplantation?
Hematological malignancies:
- AML
- ALL
- CML
- (CLL)
- (Myeloma)
- (Lymphoma)
Non-malignant disorders:
- Aplastic anemia
- Immunodeficiencies
- Hemoglobinopathies
- Metabolic storage diseases
- (Autoimmune diseases)
What are the most common indications for overall HSCT in the US? Autologous? Allogeneic?
1. Myeloma/PCD
2. NHL
Autologous: Myeloma/PCD
Allogeneic: AML (also ALL, MDS/MPD)
What preparative regimens does the HSC recipient need to undergo?
Chemo +/- radiation
- Busulfan, cyclophosphamide
Immunosuppressive agents:
- ATG (anti-thymocyte globulin)
- Monoclonal Abs (e.g. Campath: Anti-CD52)
What are the goals of conditioning regimens for the recipient?
- Ablate host immune system to ensure engraftment (not rejected)
- Eradicate malignancy to prevent relapse (leads to myeloablation)
- Minimize toxicity
What are “mini” transplants?
- Use reduced intensity or on-myeloablative conditioning regimens
- Initial mixed chimerism (i.e. donor and recipient hematopoiesis) is followed by conversion to full chimerism allowing graft vs. tumor effect (get host hematopoiesis to go away)
- Less toxicity in older pts
- Different sensitivity of different tumors
What is the process of HSC infusion?
- HSC product infused into blood stream
- HSCs home to marrow and engraft over 10-30 days
What is the best HSC product to use?
Depends on available choices and clinical scenario
Peripheral blood vs. marrow
- Speed of engraftment
- GVHD
Peripheral blood SCs:
- Faster engraftment (10-14 d vs. 20-26)
- No increase in acute GVHD
- Increased incidence of chronic GVHD
—-Maybe better disease free survival in poor risk pts, but for unrelated donors, may not always be the best
What are the pros/cons of cord blood as an HSC source?
Pros:
- Available immediately
- May induce less GVHD
Cons:
- Cell numbers may be limiting for larger pts
- Slower engraftment (up to 1 mo)
Initial studies on outcome are promising, but no long term data available yet
What is the primary type/source of HSCs in autologous transplants? Allogeneic?
Autologous: peripheral blood
Allogeneic: Peripheral blood (but significantly more of the other types than autologous)
What are the major risks of HSCT?
Autologous and Allogeneic:
- Relapse of primary disease (graft contamination or residual disease)
- Regimen related toxicity
- Immunosuppression/infection
Allogeneic only:
- Graft rejection (“host vs. graft”)
- Graft vs. host disease