Outcome After First Relapse In Adult Patients with Philadelphia Chromosome-Negative Acute Lymphoblastic Leukemia

Abstract 3084 With modern intensive chemotherapy, 78% to 93% of adult patients with acute lymphoblastic leukemia (ALL) achieve complete remission (CR). However, the disease-free survival rate is only 30% to 40% due to the high rate of relapse. A part of relapsed patients can achieve second remission (CR2) with salvage therapy, and allogeneic hematopoietic stem cell transplantation (HSCT) in CR2 will be the only curative strategy. Prognosis after relapse in adult patients with ALL is considered to be extremely poor, but reports as to the outcome after relapse have been limited. To elucidate the outcome of relapsed patients and prognostic factors after relapse, we retrospectively collected and analyzed clinical data from 69 institutions in Japan on patients with Philadelphia-chromosome (Ph) negative ALL, aged 16–65 years, who relapsed after first CR (CR1) between 1998 and 2008. A total of 332 patients were included in this study. The median age of them was 35 years, and 165 patients were male. Median duration of CR1 was 290 days (range 15–7162 days), and median follow-up time after relapse was 319 days (range 3–3689 days). Fifty-eight and 4 of them relapsed after allogeneic and autologous HSCT in CR1, respectively. The overall survival (OS) rate was not significantly different between patients who relapsed after allogeneic HSCT in CR1 and those who relapsed after chemotherapy only (50.0% vs. 43.4% at 1 year and 10.6% vs. 16.3% at 5 year, respectively). Among 270 patients who relapsed after chemotherapy only, 234 patients received salvage chemotherapy after relapse, and 123 patients achieved CR2 (52.5%). Sixty-two patients out of those 123 patients underwent allogeneic HSCT in CR2. Median duration between the achievement of CR2 with salvage chemotherapy and allogeneic HSCT in CR2 was 76 days. OS rate was significantly better in patients who underwent allogeneic HSCT in CR2 following salvage chemotherapy than those who did not (74.1% vs. 55.1% at 1 year and 44.7% vs. 11.6% at 5 year, respectively) by a landmark analysis limiting patients who were surviving without disease at 76 days after the achievement of CR2. In multivariate analysis of factors that included allogeneic HSCT in CR2 following salvage chemotherapy as a time-dependent covariate, lower white blood cell count at relapse (less than 10000/μl) and allogeneic HSCT in CR2 were associated with better OS rate among patients who achieved CR2 following salvage chemotherapy. Forty-six patients underwent allogeneic HSCT in non-CR after receiving salvage chemotherapy. A part of them survived long, and 5 year OS rate was 20.9%. In conclusion, the prognosis of adult patients with relapsed Ph-negative ALL is poor. Allogeneic HSCT after first relapse could improve the prognosis. Disclosures: No relevant conflicts of interest to declare.