Work

A Phase I/II Clinical Trial of Type 1 Interferon for Reduction of Relapse after HCT in High Risk AML

Year: 2019

Type: article

Abstract: Introduction Relapse remains a significant challenge towards improving survival after allogeneic hematopoietic transplantation (HCT) for Acute Myeloid Leukemia (AML) not in remission or possessing poor cytogenetic/molecular features. Insights from murine pre-clinical studies demonstrate a central role for CD8+ dendritic cells in cross-presentation of leukemia associated antigens (LAA) in mediating GVL without aggravating acute Graft-versus-Host Disease (aGVHD)(Toubai, Blood 2013). We posited that enhancing LAA cross-presentation with exogenous Type I Interferon (pegIFNα) would promote GVL response and reduce rates of relapse after HCT. Methods We initiated a prospective, phase I/II, clinical trial of pegIFNα administration after myeloablative conditioning for prevention of relapse in pts with detectable AML at time of HCT (resistant to induction) or with cytogenetic/molecular features conferring high relapse risk and poor survival. Pts received up to four doses of 90mcg or 180mcg pegIFNα SubQ on d -1 and d 14, 28, 42 after PBSC or BMT. aGVHD prophy was tacrolimus + MTX or MMF. The primary endpoint was to determine the incidence of relapse in pts receiving the phase II dosage of pegIFNα. We hypothesized that 30 pts assigned to the same dose would provide 80% power to detect a difference between a promising day 180 relapse rate of 40% versus a rate of 60%. Results A total of 30 pts received study treatment at a median age of 60 years (17-72). Conditioning was myeloablative FluBu (n=9), CloBu (n=20) or FluCyTBI (n=1). At time of HCT, AML was detected in 28 pts and 2 pts enrolled for poor cytogenetic/molecular risk, complex/monosomal karyotype (n=1) and FLT3-ITD+ (n=1). There was no DLT at 90mcg (n=3) and one DLT (graft failure) after escalation to 180mcg (n=27). pegIFNα was well tolerated with ≥3 doses administered to 87% of pts. ≥Grade 3 SAEs during treatment include acute kidney injury(n=1), engraftment failure(n=1), bone pain/weakness(n=1), hypotension(n=1) and hypoxemia (n=1). 29 pts (97%) experienced primary engraftment and bone marrow exam at d 30 revealed CR in 100% of pts. Thirteen pts (43%) experienced infection. Grade II-IV aGVHD and grade III-IV aGVHD occurred in 35% (20 – 56%) and 11% (4 – 30%) by day 180. The incidence of TRM was 11% (3-30%) at day 180 and 19% (8-41%) at 1-yr. The day 180 (and 1-yr) incidence of relapse was 39% (24 – 60%) in the overall cohort and 36% (20 – 58%) in 27 pts treated at the phase II dose. At a median follow up of 19 months, the 1-yr OS was 42% (27 – 65%). Conclusion These data provide initial evidence of clinical translation for pegIFNα when administered prophylactically in an AML cohort at high risk for relapse. Type I Interferon did not significantly alter toxicity or aGVHD risk and produced relatively low rates of relapse suggesting a robust GVL response. The role of type 1 IFN in reducing clinical relapse and its underlying biological mechanisms warrants additional study.

Source: Transplantation and Cellular Therapy

DOI: 10.1016/j.bbmt.2018.12.078