ISHL10 Abstract T012

Results of US intergroup trial of response-adapted chemotherapy or chemotherapy/radiation therapy based on PET for non-bulky stage I and II Hodgkin Lymphoma (HL) (CALGB/Alliance 50604)

Interim positron-emission tomography (PET) following 1-3 cycles of doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) in newly-diagnosed, non-bulky stage I and II HL patients (pts) is a useful biomarker that predicts relapse rates of ≤10% for PET- pts. Relapse rates are higher in pts who are PET+. Interim PET thus provides an opportunity to minimize treatment for the majority of pts who are interim PET - and only intensify treatment for those who are PET+. This strategy could reduce short and long term treatment toxicity for the majority of pts. To test this hypothesis, the US Intergroup conducted a phase II clinical trial, CALGB/Alliance 50604, for newly-diagnosed non-bulky stage I and II HL pts. Between 5/15/10 and 5/4/12, 164 previously untreated pts with non-bulky stages I/II HL were enrolled. Pts received 2 cycles of ABVD followed by PET. Deauville scores 1-3 were negative (≤ liver uptake), while scores of 4-5 were positive, based on central review. PET- pts received 2 more cycles of ABVD, and PET+ pts received 2 cycles of escalated BEACOPP + 3060 cGy involved-field radiation therapy (IF RT). Median age was 31 years (18-58). There were 88 males and 76 females. Pt. stages were IA (16), IB (4), IIA (90), IIB (35), IIAE (4), and IIBE (3). All pts were PET+ prior to treatment. 144/164 patients had cycle 2 PET and adequate follow-up for assessment: 131 (91%) were PET- and 13 (9%) PET+. Of 20 not analyzed, 13 were excluded (6 never treated and 2 treated with < 2 cycles) and 7 had insufficient follow up. At a median follow-up time of 2 years, 8/131 (6%) PET- pts relapsed or progressed with an estimated 3-year progression-free-survival (PFS) of 92%. 4/13 (31%) PET+ pts. failed (3 relapsed, 1 suicide) with an estimated 3-year PFS of 66%. By Cox model, observed hazard ratio comparing PET- and PET+ PFS for pts is 6.04 (1.82, 20.08). There was 1 death (suicide). These early results demonstrate that the 91% of pts PET- after 2 cycles of ABVD had an excellent PFS with total of 4 ABVD cycles. Updated results will be presented.