Treatment of MDS, AML and CMML Relapse after Allogeneic Blood Stem Cell Transplantation with Azacitidine, Lenalidomide and Donor Lymphocyte Infusions - Final Results of the Prospective Azalena-Trial (NCT02472691)

Background

Azacitidine (Aza) in combination with donor lymphocyte infusions (DLI) is an established treatment option for pts with relapse of myeloid malignancies after allo-SCT. Accounting for its immunomodulatory and anti-leukemic properties, we considered Lenalidomide (Len) to be a synergistic partner for Aza and DLI that may further improve response rate and outcome. To investigate the tolerability and efficacy of the combination of Aza, Len and DLI as first salvage therapy for relapsed MDS, AML and CMML after allo-SCT we performed a prospective, multicenter, single-arm phase-II trial. Results from two safety interim analyses have previously been reported. Here, we report the final results from this investigator-initiated trial.

Design/Methods:

Patients with relapse of MDS, AML and CMML after first allo-SCT were eligible. Envisaged treatment according to the protocol consisted of up to 8 cycles Aza (75 mg/m ²/d d1-7, every 28 days) and up to 3 DLI with increasing T cell dosages (0.5×10 ⁶ - 1.5×10 ⁷ cells/kg). Len was administered concomitantly for 21 days of a 28-day cycle. Following a positive first interim safety analysis in 10 patients the daily dose of Len was increased from 2.5 to 5mg. The primary endpoint of the study was safety, while secondary efficacy endpoints included response type and rates, time to and duration of response and overall survival.

Results:

Overall, 50 pts with molecular (n=29, 58%) or hematological (n=21, 42%) relapse of MDS (n=24, 48%), AML (n=23, 46%) or CMML (n=3, 6%) detected after median of 233 days (range, 98 to 2659) after allo-SCT were included. Fourteen patients (28%) received Len at a daily dosage of 2.5 mg and 36 patients (72%) at a daily dosage of 5 mg with no DLTs observed in the interim analyses. Median number of Len cycles per patient was 7 (range, 1 to 8) with no differences between the two dose levels. Concomitantly, 34 pts (68%) received at least one DLI (median: 3, range: 1-11).

Overall response rate (ORR) during treatment was 56% (CR n=25, 50%, PR n=3, 6%). ORR and CR rates did not differ between Len dose levels. Of interest, CR rate did not differ between pts treated at the stage of molecular relapse and those initiated at hematological relapse (52% vs. 48%). Median time to CR was 112 days (range 1-286) corresponding to 4 cycles (range 1 to 8). At the time of data lock, 20 patients (80%) were still in CR without additional therapy for a median of 15 months, while 5 patients (20%) had relapsed again after a median of 8 months. With a median follow-up of 20 months median OS was 21 months and 1-year OS rate 65%.

While therapy-related CTC grade III/IV neutropenia (92%), thrombopenia (80%) or anemia (36%) occurred frequently, drug-related non-hematological adverse events (AE) >grade II were rare and mainly consisted of gastrointestinal toxicity (6%), laboratory findings (28%) and infections (22%). Twenty-three pts (46%) developed acute GvHD including 5 patients (10%) with grade III/IV aGvHD, and 26 pts (52%) chronic GvHD (mild n=10; moderate n=11; severe n=5). During the study period, 3 secondary malignancies (squamous cell, basal cell and vulvar carcinoma) occurred. There were no therapy related deaths.

Conclusion:

Len up to a dosage to 5 mg/day can be safely added to the combination of AZA and DLI without excess of GvHD and toxicity. Furthermore, these data suggest that the combination of Aza, Len and DLI has promising clinical activity for relapse of myeloid malignancies after allo-SCT and is able to induce durable responses and survival in a substantial proportion of pts.