OVERVIEW• The annual incidence of pediatric acute leukemia is approximately 8,300 patients in major markets1,2

– Current treatments are generally effective for most pediatric patients with ALL, the most common type of acute leukemia in children, with more than 95% achieving remission and event-free/long-term survival rates approaching 80%

• MLL-rearrangement (MLL-r) occurs in about 15% of pediatric acute leukemia cases (approximately 1,300 patients in major markets) and has the poorest prognosis of any acute leukemia subset3,4,5,6

– There are no approved therapies today specifically indicated for MLL-r patients

• Epizyme is conducting clinical trials of EPZ-5676 as a potential personalized therapeutic for pediatric and adult patients with MLL-r acute leukemias

PATIENT FACTSPediatric ALL >Incidence: ~6,600 (major markets)Average Age at Presentation: 2-3 yearsDiagnosis: Morphologic, immunophenotypic, and genetic evaluation of blood cellsStandard of Care: Intensive combination chemotherapy (includes anthracyclines, vinka alkyloids, steroids, and asparaginases)1

Survival: 95% of patients achieve remission, 80% are long-term survivors1

Pediatric AML >Incidence: ~1,700 (major markets)Average Age at Presentation: 2 yearsDiagnosis: Histochemical, cytogenetic, and molecular evaluation of blood cellsStandard of Care: Systemic combination chemotherapy (including cytarabine and anthracyclines)2

Survival: 45% to 55% 5-year event-free survival; younger children have better prognosis2

Pediatric ALL with MLL-r >Incidence: ~980 (major markets)Average Age at Presentation: Infants 3-12 monthsTypical Translocations: MLL-AF4 (other translocations do occur)3,4,5

Standard of Care: Intensive, multi-year combination chemotherapy Relapsed or Refractory Disease: No standard treatment aside from allogeneic stem cell transplantationSurvival: 27% of patients achieve 5-year event-free survival for MLL-AF43,4,5

Pediatric AML with MLL-r >Incidence: ~280 (major markets)Average Age at Presentation: Less than 2 years and older than 10Typical Translocations: MLL-AF9 (other translocations do occur)6

Standard of Care: Systemic combination chemotherapyRelapsed or Refractory Disease: No standard treatment aside from allogeneic stem cell transplantationSurvival: 45% of patients achieve 5-year event-free survival for MLL-AF9; some translocations have worse prognosis (e.g. 11%)6

CLINICAL TRIALS WITH EPZ-5676• Epizyme is conducting a Phase 1b study of EPZ-5676

in pediatric patients age 3 months to 18 years with MLL-r acute leukemias

• Epizyme is also conducting a clinical trial of EPZ-5676 in adult patients with MLL-r and MLL-PTD acute leukemias

• For more information visit ClinicalTrials.gov

Kaplan-Meier analysis shows MLL-AF4 (orange line), the most common translocation partner in pediatric ALL MLL-r patients, has poor prognosis (26.7 ± 11.4 percent). BCR-ABL subset (blue line) had a similarly poor prognosis before approval of imatinib (Gleevec) and now has a favorable treatment outcome.

Pediatric Acute Leukemia Fact Sheet

REFERENCES1. NCI, Childhood ALL Treatment PDQ2. NCI, Childhood AML Treatment PDQ3. Pui CH, NEJM, 2004 4. Pieters R, Lancet, 2007 5. Rubnitz JE, JCO, 19996. Balgobind BV, Blood, 2009

Event-free Survival by Subtype of Leukemia in 467 Children with ALL Treated at St. Jude’s Children’s Research Hospital, 1991-1999.

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