TNC dose can affect PFS, OS after PBSCT

GRAPEVINE, TEXAS—The total nucleated cell (TNC) dose delivered in an allogeneic peripheral blood stem cell transplant (allo-PBSCT) can affect outcomes in certain patients, according to a study presented at the 2014 BMT Tandem Meetings.

Researchers found that a higher TNC dose was associated with better progression-free survival (PFS) and overall survival (OS) among patients who received allo-PBSCT with reduced-intensity conditioning (RIC) and total-body irradiation (TBI).

On the other hand, the dose of CD3+, CD4+, CD8+, or CD34+ cells did not have a significant impact on survival rates in these patients.

And none of the cell doses studied had a significant impact in patients who did not receive TBI or in those who received TBI with myeloablative conditioning.

Michael Burns, of Roswell Park Cancer Institute in Buffalo, New York, presented these findings at the meeting as abstract 12.*

Burns noted that studies have produced conflicting results regarding the correlation between patient outcomes and the dose of CD34+, CD3+, CD4+, or CD8+ cells given in allo-PBSCT. In addition, TNC dose has not been analyzed much in the context of PBSCTs.

Therefore, he and his colleagues retrospectively analyzed graft cell composition in 254 patients who received their first allo-PBSCT from January 2001 to September 2012.

Fifty-eight percent of the patients were male, and the median age was 50 (range, 19-73 years). Forty-four percent of patients had acute myeloid leukemia, 18% had myelodysplastic syndromes or myeloproliferative neoplasms, 13% had acute lymphoblastic leukemia, 13% had non-Hodgkin lymphoma, and 12% had other diseases.

Of the 254 patients studied, 93 had received TBI. Among these, 53 received myeloablative conditioning (91% cyclophosphamide, 120 cGy), and 40 received RIC (100% fludarabine and melphalan, 400 cGy).

Of the 161 patients who did not receive TBI, 41 received myeloablative conditioning (88% busulfan and cyclophosphamide), and 120 received RIC (87% fludarabine and melphalan).

Patients received T-cell-replete, G-CSF mobilized, PB allografts. Fifty-six percent had a 6/6 HLA matched related donor, and 44% had an 8/8 HLA matched unrelated donor. Forty-nine percent of patients were in complete remission at the time of transplant.

The researchers analyzed cell doses according to the median dose (above vs below). But they also analyzed CD34+ dose as < 4 x 10⁶ cells/kg vs ≥ 4 x 10⁶ cells/kg and as < 4 x 10⁶ cells/kg vs 4 to 8 x 10⁶ cells/kg vs > 8 x 10⁶ cells/kg. They analyzed TNC as < 8 x 10⁸ cells/kg vs ≥ to 8 x 10⁸ cells/kg.

The team found that a CD34+ cell dose greater than 4 x 10⁶ cells/kg was significantly associated with time to platelet engraftment in all patients. It was also associated with time to neutrophil engraftment in the TBI group, but this was predominantly among patients who received RIC.

On the other hand, CD3+, CD4+, CD8+, and TNC doses were not significantly associated with platelet or neutrophil engraftment in any patients.

CD34+, CD3+, CD4+, and CD8+ cell dose were not associated with OS, PFS, or acute graft-vs-host disease (GVHD). And TNC had no significant effect on acute GVHD.

“However, we did find that the TNC dose did show some pretty interesting survival outcomes,” Burns said.

A higher TNC dose (≥ 8 x10⁸ cells/kg) was associated with significantly better PFS (P=0.027) and OS (P=0.018) in the TBI patients but not in patients who did not receive TBI (P>0.1 for PFS and OS).

When they analyzed patients according to conditioning regimen, the researchers found the association retained significance among patients who received RIC (P=0.01 for PFS and P=0.007 for OS) but not among patients who received myeloablative conditioning (P>0.1 for PFS and OS).

Burns and his colleagues also conducted a multivariate analysis to see if any other factors affected the relationship between TNC and survival. They controlled for patient age, Karnofsky performance status, and body mass index. And they stratified patients into 4 groups according to TBI and conditioning regimen.

The results showed that patients who received TBI and RIC, as well as a TNC dose less than 8 x 10⁸ cells/kg, had a relative risk of 3.3 for PFS (P=0.026) and a relative risk of 3.4 for OS (P=0.021).

“The association of higher TNC dose with better progression-free and overall survival implies there is a population of nucleated cells which mitigate GVHD but enhance the [graft-vs-leukemia] effect after reduced-intensity TBI conditioning,” Burns said.

“Myeloablative conditioning regimens result in more direct tumor killing. Thus, they rely less on the graft-vs-leukemia effect than the RIC regimens.”

He also noted that the lack of an association between TNC dose and survival rates with non-TBI-based regimens implies there are different mechanisms of tumor kill with TBI and non-TBI-containing regimens.

And a more detailed analysis of cell population subsets in apheresis product may allow researchers to identify cell populations that could improve patient outcomes.

*Some data in the abstract differ from data presented at the meeting.

GRAPEVINE, TEXAS—The total nucleated cell (TNC) dose delivered in an allogeneic peripheral blood stem cell transplant (allo-PBSCT) can affect outcomes in certain patients, according to a study presented at the 2014 BMT Tandem Meetings.

Researchers found that a higher TNC dose was associated with better progression-free survival (PFS) and overall survival (OS) among patients who received allo-PBSCT with reduced-intensity conditioning (RIC) and total-body irradiation (TBI).

On the other hand, the dose of CD3+, CD4+, CD8+, or CD34+ cells did not have a significant impact on survival rates in these patients.

And none of the cell doses studied had a significant impact in patients who did not receive TBI or in those who received TBI with myeloablative conditioning.

Michael Burns, of Roswell Park Cancer Institute in Buffalo, New York, presented these findings at the meeting as abstract 12.*

Burns noted that studies have produced conflicting results regarding the correlation between patient outcomes and the dose of CD34+, CD3+, CD4+, or CD8+ cells given in allo-PBSCT. In addition, TNC dose has not been analyzed much in the context of PBSCTs.

Therefore, he and his colleagues retrospectively analyzed graft cell composition in 254 patients who received their first allo-PBSCT from January 2001 to September 2012.

Fifty-eight percent of the patients were male, and the median age was 50 (range, 19-73 years). Forty-four percent of patients had acute myeloid leukemia, 18% had myelodysplastic syndromes or myeloproliferative neoplasms, 13% had acute lymphoblastic leukemia, 13% had non-Hodgkin lymphoma, and 12% had other diseases.

Of the 254 patients studied, 93 had received TBI. Among these, 53 received myeloablative conditioning (91% cyclophosphamide, 120 cGy), and 40 received RIC (100% fludarabine and melphalan, 400 cGy).

Of the 161 patients who did not receive TBI, 41 received myeloablative conditioning (88% busulfan and cyclophosphamide), and 120 received RIC (87% fludarabine and melphalan).

Patients received T-cell-replete, G-CSF mobilized, PB allografts. Fifty-six percent had a 6/6 HLA matched related donor, and 44% had an 8/8 HLA matched unrelated donor. Forty-nine percent of patients were in complete remission at the time of transplant.

The researchers analyzed cell doses according to the median dose (above vs below). But they also analyzed CD34+ dose as < 4 x 10⁶ cells/kg vs ≥ 4 x 10⁶ cells/kg and as < 4 x 10⁶ cells/kg vs 4 to 8 x 10⁶ cells/kg vs > 8 x 10⁶ cells/kg. They analyzed TNC as < 8 x 10⁸ cells/kg vs ≥ to 8 x 10⁸ cells/kg.

The team found that a CD34+ cell dose greater than 4 x 10⁶ cells/kg was significantly associated with time to platelet engraftment in all patients. It was also associated with time to neutrophil engraftment in the TBI group, but this was predominantly among patients who received RIC.

On the other hand, CD3+, CD4+, CD8+, and TNC doses were not significantly associated with platelet or neutrophil engraftment in any patients.

CD34+, CD3+, CD4+, and CD8+ cell dose were not associated with OS, PFS, or acute graft-vs-host disease (GVHD). And TNC had no significant effect on acute GVHD.

“However, we did find that the TNC dose did show some pretty interesting survival outcomes,” Burns said.

A higher TNC dose (≥ 8 x10⁸ cells/kg) was associated with significantly better PFS (P=0.027) and OS (P=0.018) in the TBI patients but not in patients who did not receive TBI (P>0.1 for PFS and OS).

When they analyzed patients according to conditioning regimen, the researchers found the association retained significance among patients who received RIC (P=0.01 for PFS and P=0.007 for OS) but not among patients who received myeloablative conditioning (P>0.1 for PFS and OS).

Burns and his colleagues also conducted a multivariate analysis to see if any other factors affected the relationship between TNC and survival. They controlled for patient age, Karnofsky performance status, and body mass index. And they stratified patients into 4 groups according to TBI and conditioning regimen.

The results showed that patients who received TBI and RIC, as well as a TNC dose less than 8 x 10⁸ cells/kg, had a relative risk of 3.3 for PFS (P=0.026) and a relative risk of 3.4 for OS (P=0.021).

“The association of higher TNC dose with better progression-free and overall survival implies there is a population of nucleated cells which mitigate GVHD but enhance the [graft-vs-leukemia] effect after reduced-intensity TBI conditioning,” Burns said.

“Myeloablative conditioning regimens result in more direct tumor killing. Thus, they rely less on the graft-vs-leukemia effect than the RIC regimens.”

He also noted that the lack of an association between TNC dose and survival rates with non-TBI-based regimens implies there are different mechanisms of tumor kill with TBI and non-TBI-containing regimens.

And a more detailed analysis of cell population subsets in apheresis product may allow researchers to identify cell populations that could improve patient outcomes.

*Some data in the abstract differ from data presented at the meeting.

GRAPEVINE, TEXAS—The total nucleated cell (TNC) dose delivered in an allogeneic peripheral blood stem cell transplant (allo-PBSCT) can affect outcomes in certain patients, according to a study presented at the 2014 BMT Tandem Meetings.

Researchers found that a higher TNC dose was associated with better progression-free survival (PFS) and overall survival (OS) among patients who received allo-PBSCT with reduced-intensity conditioning (RIC) and total-body irradiation (TBI).

On the other hand, the dose of CD3+, CD4+, CD8+, or CD34+ cells did not have a significant impact on survival rates in these patients.

And none of the cell doses studied had a significant impact in patients who did not receive TBI or in those who received TBI with myeloablative conditioning.

Michael Burns, of Roswell Park Cancer Institute in Buffalo, New York, presented these findings at the meeting as abstract 12.*

Burns noted that studies have produced conflicting results regarding the correlation between patient outcomes and the dose of CD34+, CD3+, CD4+, or CD8+ cells given in allo-PBSCT. In addition, TNC dose has not been analyzed much in the context of PBSCTs.

Therefore, he and his colleagues retrospectively analyzed graft cell composition in 254 patients who received their first allo-PBSCT from January 2001 to September 2012.

Fifty-eight percent of the patients were male, and the median age was 50 (range, 19-73 years). Forty-four percent of patients had acute myeloid leukemia, 18% had myelodysplastic syndromes or myeloproliferative neoplasms, 13% had acute lymphoblastic leukemia, 13% had non-Hodgkin lymphoma, and 12% had other diseases.

Of the 254 patients studied, 93 had received TBI. Among these, 53 received myeloablative conditioning (91% cyclophosphamide, 120 cGy), and 40 received RIC (100% fludarabine and melphalan, 400 cGy).

Of the 161 patients who did not receive TBI, 41 received myeloablative conditioning (88% busulfan and cyclophosphamide), and 120 received RIC (87% fludarabine and melphalan).

Patients received T-cell-replete, G-CSF mobilized, PB allografts. Fifty-six percent had a 6/6 HLA matched related donor, and 44% had an 8/8 HLA matched unrelated donor. Forty-nine percent of patients were in complete remission at the time of transplant.

The researchers analyzed cell doses according to the median dose (above vs below). But they also analyzed CD34+ dose as < 4 x 10⁶ cells/kg vs ≥ 4 x 10⁶ cells/kg and as < 4 x 10⁶ cells/kg vs 4 to 8 x 10⁶ cells/kg vs > 8 x 10⁶ cells/kg. They analyzed TNC as < 8 x 10⁸ cells/kg vs ≥ to 8 x 10⁸ cells/kg.

The team found that a CD34+ cell dose greater than 4 x 10⁶ cells/kg was significantly associated with time to platelet engraftment in all patients. It was also associated with time to neutrophil engraftment in the TBI group, but this was predominantly among patients who received RIC.

On the other hand, CD3+, CD4+, CD8+, and TNC doses were not significantly associated with platelet or neutrophil engraftment in any patients.

CD34+, CD3+, CD4+, and CD8+ cell dose were not associated with OS, PFS, or acute graft-vs-host disease (GVHD). And TNC had no significant effect on acute GVHD.

“However, we did find that the TNC dose did show some pretty interesting survival outcomes,” Burns said.

A higher TNC dose (≥ 8 x10⁸ cells/kg) was associated with significantly better PFS (P=0.027) and OS (P=0.018) in the TBI patients but not in patients who did not receive TBI (P>0.1 for PFS and OS).

When they analyzed patients according to conditioning regimen, the researchers found the association retained significance among patients who received RIC (P=0.01 for PFS and P=0.007 for OS) but not among patients who received myeloablative conditioning (P>0.1 for PFS and OS).

Burns and his colleagues also conducted a multivariate analysis to see if any other factors affected the relationship between TNC and survival. They controlled for patient age, Karnofsky performance status, and body mass index. And they stratified patients into 4 groups according to TBI and conditioning regimen.

The results showed that patients who received TBI and RIC, as well as a TNC dose less than 8 x 10⁸ cells/kg, had a relative risk of 3.3 for PFS (P=0.026) and a relative risk of 3.4 for OS (P=0.021).

“The association of higher TNC dose with better progression-free and overall survival implies there is a population of nucleated cells which mitigate GVHD but enhance the [graft-vs-leukemia] effect after reduced-intensity TBI conditioning,” Burns said.

“Myeloablative conditioning regimens result in more direct tumor killing. Thus, they rely less on the graft-vs-leukemia effect than the RIC regimens.”

He also noted that the lack of an association between TNC dose and survival rates with non-TBI-based regimens implies there are different mechanisms of tumor kill with TBI and non-TBI-containing regimens.

And a more detailed analysis of cell population subsets in apheresis product may allow researchers to identify cell populations that could improve patient outcomes.

*Some data in the abstract differ from data presented at the meeting.