Chimeric antigen receptor T-cell therapy in acute myeloid leukemia.

PURPOSE OF REVIEW: Treatment outcome of relapsed or refractory AML patients remains dismal and new treatment options are needed. Adoptive cell therapy using CAR-T cells is a potentially interesting approach in this. RECENT FINDINGS: Several potentially interesting AML targets are being investigated with CAR-T therapy with over 60 clinical trials listed on clinicaltrials.gov. The first clinical data are only just emerging with mixed results, once more proving that further research is needed. SUMMARY: Adoptive cell therapy using chimeric antigen receptor T cells is being investigated in AML through many clinical trials. So far, no AML-specific antigen has been identified, requiring additional strategies to mitigate on-target off-tumor toxicity and to increase efficacy. Focus point is to acquire control over the CAR T cells once administered. Strategies to do so include biodegradable CARs, inducible CARs, suicide-switch containing CARs and two-component modular CARs. Limited and mixed results are available, confirming the risk of lasting toxicity for nonswitchable CARs. Initial results of modular CARs suggest toxicity can be mitigated whilst maintaining CAR activity by the use of modular CAR concepts that allows for 'ON' and 'OFF' switching.

Platelet doubling after the first azacitidine cycle is a promising predictor for response in myelodysplastic syndromes (MDS), chronic myelomonocytic leukaemia (CMML) and acute myeloid leukaemia (AML) patients in the Dutch azacitidine compassionate named patient programme.

The efficacy of azacitidine in the treatment of high-risk myelodysplastic syndromes (MDS), chronic myelomonocytic leukaemia (CMML) and acute myeloid leukaemia (AML) (20-30% blasts) has been demonstrated. To investigate the efficacy of azacitidine in daily clinical practice and to identify predictors for response, we analysed a cohort of 90 MDS, CMML and AML patients who have been treated in a Dutch compassionate named patient programme. Patients received azacitidine for a median of five cycles (range 1-19). The overall response rate (complete/partial/haematological improvement) was 57% in low risk MDS, 53% in high risk MDS, 50% in CMML, and 39% in AML patients. Median overall survival (OS) was 13·0 (9·8-16·2) months. Multivariate analysis confirmed circulating blasts [Hazard Ratio (HR) 0·48, 95% confidence interval (CI) 0·24-0·99; P = 0·05] and poor risk cytogenetics (HR 0·45, 95% CI 0·22-0·91; P = 0·03) as independent predictors for OS. Interestingly, this analysis also identified platelet doubling after the first cycle of azacitidine as a simple and independent positive predictor for OS (HR 5·4, 95% CI 0·73-39·9; P = 0·10). In conclusion, routine administration of azacitidine to patients with variable risk groups of MDS, CMML and AML is feasible, and subgroups with distinct efficacy of azacitidine treatment can be identified.

Analysis of efficacy and prognostic factors of lenalidomide treatment as part of a Dutch compassionate use program.

BACKGROUND AND METHODS: To obtain efficacy and safety data on lenalidomide treatment outside of clinical trials, we analyzed the clinical data of 114 patients with refractory or relapsed multiple myeloma treated with lenalidomide on a compassionate use basis. The recommended treatment consisted of lenalidomide 25 mg given on days 1-21 of a 28-day cycle, in combination with dexamethasone. A median of 3 previous lines of therapy were given, including thalidomide in 91%. Most patients were treated until progression or intolerable toxicity. RESULTS: The median number of cycles was 7 (range, 1-21+ cycles) with a maximum response after a median of 3 cycles (range, 1-10 cycles). The overall response rate was 69%, including complete response in 6%, very good partial response in 19%, and partial response in 44%. The response rate was not influenced by previous thalidomide and/or bortezomib treatment. The median time to progression (TTP) was 9 months and the median overall survival (OS) was 22 months. A significantly longer TTP was observed in patients who previously underwent allogeneic stem cell transplantation (12.5 months vs. 8 months; P = .036). Overall survival was significantly affected by performance status (P < .0001). Lenalidomide toxicity was predominantly hematologic (37%; Common Toxicity Criteria > or = 3) and the incidence of venous thrombotic events was low (5%) using the recommended prophylaxis. CONCLUSION: This analysis confirms that, outside clinical prospective trials, treatment with lenalidomide is highly effective and feasible in heavily pretreated patients with multiple myeloma.