Written in Blood
Could Cord Blood Transplantation Cure Refractory Severe Aplastic Anemia ?
In children and young adults with refractory severe aplastic anemia ( SAA ) without matched , unrelated donors , cord blood transplantation was associated with low rates of engraftment failure and high rates of one-year overall survival ( OS ), according to a small , prospective , phase II study published in Blood .
“ Most [ patients with ] refractory SAA do not respond to eltrombopag or other secondline treatment and are therefore exposed to life-threatening infections and bleeding ,” lead author Régis Peffault de Latour , MD , PhD , of Saint-Louis Hospital in Paris , told ASH Clinical News . “ Cord blood transplantation with at least 4 × 10 7 frozen nucleated cells / kg is a valuable curative option in young patients with refractory idiopathic SAA and no available matched unrelated donors .”
• anti-thymocyte globulin 2.5 mg / kg per day ( day 3 and day 2 ) for a total dose of 5 mg / kg
• 2 Gy total body irradiation ( day 2 )
Time from diagnosis to transplant was long ( median = 12 months ; range = 8.7-17.8 months ) and most patients had at least 20 platelet and red blood cell transfusions , reflecting “ heavily refractory disease ,” the authors noted . ( See TABLE 3 for patients ’ pre-transplant characteristics .)
The study ’ s primary endpoint was one-year survival rates of at least 50 percent . Secondary endpoints included cumulative incidences of engraftment , acute and chronic GVHD , infections , and SAA relapse .
Three patients did not undergo transplant : One patient had a male unrelated donor available ( n = 1 ), one was diagnosed with dyskeratosis congenita ( n = 1 ),
“These results justify using a minimal anti-thymocyte globulin dose of 5 mg / kg , … which may also lower nonengraftment rates .”
— RÉGIS PEFFAULT DE LATOUR , MD , PhD
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This study enrolled 29 patients ( median age = 16 years ; range = 9-23 years ) who presented with primaryrefractory SAA approximately six months following firstline immunosuppressive therapy , consisting of anti-thymocyte globulin and cyclosporine . Those with relapsed SAA who were refractory to secondline immunosuppressive therapy and without a matched unrelated donor were also eligible for inclusion if they had one or two unrelated units of cord blood containing more than 4 × 10 7 frozen nucleated cells / kg available .
Pre-transplant conditioning consisted of :
• fludarabine 30 mg / m 2 per day ( day 6 to day 3 )
• cyclophosphamide 30 mg / kg per day ( day 6 to day 3 )
32 ASH Clinical News