Durable response after tisagenlecleucel in adults with relapsed/refractory follicular lymphoma: ELARA trial update

ABSTRACT

Tisagenlecleucel is approved for adults with relapsed/refractory (r/r) follicular lymphoma (FL) in the third- or later-line setting. The primary analysis (median follow-up, 17 months) of the phase 2 ELARA trial reported high response rates and excellent safety profile in patients with extensively pretreated r/r FL. Here, we report longer-term efficacy, safety, pharmacokinetic, and exploratory biomarker analyses after median follow-up of 29 months (interquartile range, 22.2-37.7). As of 29 March 2022, 97 patients with r/r FL (grades 1-3A) received tisagenlecleucel infusion (0.6 × 108-6 × 108 chimeric antigen receptor-positive viable T cells). Bridging chemotherapy was allowed. Baseline clinical factors, tumor microenvironment, blood soluble factors, and circulating blood cells were correlated with clinical response. Cellular kinetics were assessed by quantitative polymerase chain reaction. Median progression-free survival (PFS), duration of response (DOR), and overall survival (OS) were not reached. Estimated 24-month PFS, DOR, and OS rates in all patients were 57.4% (95% confidence interval [CI], 46.2-67), 66.4% (95% CI, 54.3-76), and 87.7% (95% CI, 78.3-93.2), respectively. Complete response rate and overall response rate were 68.1% (95% CI, 57.7-77.3) and 86.2% (95% CI, 77.5-92.4), respectively. No new safety signals or treatment-related deaths were reported. Low levels of tumor-infiltrating LAG3+CD3+ exhausted T cells and higher baseline levels of naïve CD8+ T cells were associated with improved outcomes. Tisagenlecleucel continued to demonstrate highly durable efficacy and a favorable safety profile in this extended follow-up of 29 months in patients with r/r FL enrolled in ELARA. This trial was registered at www.clinicaltrials.gov as #NCT03568461.

Interim analysis of neoadjuvant chemoradiotherapy with sequential ipilimumab and nivolumab in rectal cancer (CHINOREC): A prospective randomized, open-label, multicenter, phase II clinical trial

e15604

Background: Immune checkpoint inhibitors (ICI) do not seem to be effective in solid cancers, which lack an immunogenic priming. Radiotherapy (RT) can induce an immunogenic cell death (ICD) and thereby restore the susceptibility to ICI, especially in microsatellite stable (MSS) cancers. This study evaluates safety, tolerability and feasibility of neoadjuvant chemoradiotherapy (CRT) with concomitant ipilimumab (IPI) and nivolumab (NIVO) in locally advanced rectal cancer (LARC). Here we present the first requisite interim analysis. Methods: This is a prospective, randomized, open-label, multicenter, phase II investigator- initiated trial (IIT). Key eligibility criteria are patients with LARC and the medical need for a neoadjuvant CRT, without metastatic disease that is considered incurable by local therapies. In total 80 patients will be randomized (ratio 30:50) to receive either neoadjuvant CRT alone (50 Gy in 2 Gy fractions over 25 working days + concurrent capecitabine 1650 mg/m2/d PO) or in combination with a single dose of IPI 1 mg/kg IV at day 7, following 3 cycles of NIVO 3 mg/kg IV Q2W, starting on day 14. Patients undergo surgery within 10-12 weeks post CRT. The primary endpoint is safety of neoadjuvant CRT with sequential IPI and NIVO following surgical resection. Surgical complications are graded by the “Clavien-Dindo Classification” v2.0 and treatment-related adverse events (TRAEs) by the Common Terminology Criteria of Adverse Events (CTCAE) v5.0. Interim analyses for the surgical complication “reoperation” will be assessed after every 10th patient in the IPI/NIVO treatment arm. Reoperation numbers are compared to historically known and published ratios. If the observed case numbers are above the calculated upper 95% confidence interval (95% CIup), the study will be terminated. Results: From 06/2020-02/2022, 36 patients have been accrued, of whom 23 were randomized to the CRT+IPI/NIVO arm. Of these, the first 10 patients who underwent successful surgery were used for the present interim analysis. No patient experienced a surgical complication with the need for a reoperation (3Grade IIIb). Any surgical complication occurred in 8 (80%) patients, with the most common being Grade I (70%) and Grade II (50%) events. Conclusions: The addition of sequentially applied IPI and NIVO to neoadjuvant CRT does not increase the number of surgical reoperation rates. The study meets it’s interim analysis criteria to be safe to continue accrual. Clinical trial information: NCT04124601.

Tisagenlecleucel in adult relapsed or refractory follicular lymphoma: the phase 2 ELARA trial

Tisagenlecleucel is an autologous anti-CD19 chimeric antigen receptor-T cell therapy with clinically meaningful outcomes demonstrated in patients with relapsed/refractory (r/r) B-cell lymphoma. In a previous pilot study of tisagenlecleucel in r/r follicular lymphoma (FL), 71% of patients achieved a complete response (CR). Here we report the primary, prespecified interim analysis of the ELARA phase 2 multinational trial of tisagenlecleucel in adults with r/r FL after two or more treatment lines or who relapsed after autologous stem cell transplant (no. NCT03568461). The primary endpoint was CR rate (CRR). Secondary endpoints included overall response rate (ORR), duration of response, progression-free survival, overall survival, pharmacokinetics and safety. As of 29 March 2021, 97/98 enrolled patients received tisagenlecleucel (median follow-up, 16.59 months; interquartile range, 13.8-20.21). The primary endpoint was met. In the efficacy set (n = 94), CRR was 69.1% (95% confidence interval, 58.8-78.3) and ORR 86.2% (95% confidence interval, 77.5-92.4). Within 8 weeks of infusion, rates of cytokine release syndrome were 48.5% (grade ≥3, 0%), neurological events 37.1% (grade ≥3, 3%) and immune effector cell-associated neurotoxicity syndrome (ICANS) 4.1% (grade ≥3, 1%) in the safety set (n = 97), with no treatment-related deaths. Tisagenlecleucel is safe and effective in extensively pretreated r/r FL, including in high-risk patients.

Neoadjuvant chemoradiotherapy with sequential ipilimumab and nivolumab in rectal cancer (CHINOREC): A prospective randomized, open-label, multicenter, phase II clinical trial

TPS3623

Background: Immune checkpoint inhibitors (ICI), such as ipilimumab (anti-cytotoxic T-lymphocyte-associated protein 4) or nivolumab (anti-programmed cell death protein 1) have been proven to be an effective strategy in solid cancers. However, ICI seem not to be effective in microsatellite stable (MSS) cancers. As they might lack an immunogenic priming, radiotherapy (RT) is capable to induce an immunogenic cell death (ICD) and subsequently an immunogenic tumor immune microenvironment (TIME). Thus, RT might restore the susceptibility of MSS tumors to ICI and consequently leading to an effective anti-tumor immune response. Methods: This is a prospective, randomized, open-label, multicenter, phase II investigator-initiated clinical trial (IIT), including patients with locally advanced rectal cancer (LARC). Patients receive either neoadjuvant chemoradiotherapy (CRT) alone (50 Gy in 2 Gy fractions over 25 working days + capecitabine 1650 mg/m2/d PO) or in combination with ipilimumab (1 mg/kg IV on day 7) and nivolumab (3 mg/kg IV on day 14, 28 and 42). Patients will undergo surgery within 10-12 weeks post CRT. The primary endpoint is incidence of treatment-emergent adverse events (AEs) assessed by the Clavien-Dindo classification of surgical complications and the common terminology criteria of adverse events (CTCAE). Secondary objectives are radiographic and pathological therapy response. Serial liquid (plasma, serum and peripheral blood mononuclear cells) and tissue biopsies will be taken before, during and after neoadjuvant treatment. Genomic, transcriptomic, epigenomic and proteomic pattern of liquid and tissue biopsies, as well as the immune cell infiltrate of resected specimen, will be correlated with therapy response and clinical outcome. Currently 8 of planned 80 patients have been enrolled. Registration numbers: NCT no. NCT04124601, EudraCT no. 2019-003865-17. Clinical trial information: NCT04124601.

Conventional versus reverse sequence of neoadjuvant epirubicin/cyclophosphamide and docetaxel: sequencing results from ABCSG-34

BACKGROUND

Preoperative chemotherapy containing anthracyclines and taxanes is well established in early-stage breast cancer. Previous studies have suggested that the chemotherapy sequence may matter but definitive evidence is missing. ABCSG trial 34 evaluated the activity of the MUC1 vaccine tecemotide when added to neoadjuvant treatment; the study provided the opportunity for the second randomisation to compare two different anthracycline/taxane sequences.

METHODS

HER2-negative early-stage breast cancer patients were recruited to this randomised multicentre Phase 2 study. Patients in the chemotherapy cohort (n = 311) were additionally randomised to a conventional or reversed sequence of epirubicin/cyclophosphamide and docetaxel. Residual cancer burden (RCB) with/without tecemotide was defined as primary study endpoint; RCB in the two chemotherapy groups was a key secondary endpoint.

RESULTS

No significant differences in terms of RCB 0/I (40.1% vs. 37.2%; P = 0.61) or pathologic complete response (pCR) rates (24.3% vs. 25%, P = 0.89) were observed between conventional or reverse chemotherapy sequence. No new safety signals were reported, and upfront docetaxel did not result in decreased rates of treatment delay or discontinuation.

CONCLUSION

Upfront docetaxel did not improve chemotherapy activity or tolerability; these results suggest that upfront neoadjuvant treatment with anthracyclines remains a valid option.

A multicenter retrospective evaluation of Chronic Myeloid Leukemia (CML) therapy in Austria assessing the impact of early treatment response on patient outcomes in a real-life setting : R-EFECT study

Background

Several clinical trials in chronic phase (CP) chronic myeloid leukemia (CML) showed that early response to tyrosine kinase inhibitor (TKI) treatment results in an improved long-term survival and progression-free survival. This study assessed whether patients achieving early treatment response (ETR; partial cytogenetic response or BCR-ABL1 mRNA ≤10% at 3 months) in daily practice also have a long-term survival benefit.

Methods

The Retrospective Evaluation of Early response in CML for long-term Treatment outcome (R-EFECT), a multicenter, retrospective chart review, documented patients with newly diagnosed CML-CP starting first-line TKI therapy in routine clinical practice. The primary aim was to assess the 5‑year overall survival rate.

Results

Of the 211 patients from 12 centers across Austria (January 2004–May 2010), 176 (median age, 56 years) were included in the analysis. All patients received first-line therapy with imatinib. Overall, 136 patients (77.3%) achieved ETR (ETR+ group), whereas 40 (22.7%) did not reach ETR (ETR− group). The ETR+ group had higher 5‑year overall survival (92.5% vs. 77.5%, P = 0.018) and progression-free survival (95.6% vs. 87.5%, P = 0.06) rates compared with the ETR− group. As expected, more patients in the ETR− group were switched to another TKI. At the last contact, 120 patients were still on imatinib and 44 had switched to another TKI (25 to nilotinib, 15 to dasatinib, and 4 to bosutinib).

Conclusion

The data are in line with randomized trials demonstrating that ETR is associated with improved survival and thus confirmed these results in patients treated in daily clinical routine.

The EndoPredict score predicts response to neoadjuvant chemotherapy and neoendocrine therapy in hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer patients from the ABCSG-34 trial

BACKGROUND

Neoadjuvant chemotherapy (NaCT) and neoadjuvant endocrine therapy (NET) can reduce pre-operative tumour burden in patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative early-stage breast cancer. This prospective translational study assessed the ability of a 12-gene molecular score (MS; EndoPredict®) to predict response to NaCT or NET within the ABCSG-34 trial.

PATIENTS AND METHODS

Hormone receptor (HR)-positive, HER2-negative samples from patients in the ABCSG-34 randomized phase II trial were selected and EndoPredict testing was performed to generate a 12-gene MS. ABCSG-34 patients were assigned to receive either NaCT or NET based on menopausal status, HR expression, grade and Ki67. Response was measured by residual cancer burden (RCB).

RESULTS

Patients selected for NaCT generally had high-risk disease by 12-gene MS (125/134), while slightly more patients treated with NET had low-risk disease (44/83). Low-risk NaCT-treated and high-risk NET-treated tumours responded poorly (NPV 100% [95% CI 66.4%-100%] and NPV 92.3% [95% CI 79.1%-98.4%], respectively]. The 12-gene MS significantly predicted treatment response for NaCT (AUC 0.736 [95% CI 0.63-0.84]) and NET (AUC 0.726 [95% CI 0.60-0.85]).

CONCLUSIONS

The 12-gene MS predicted RCB after treatment with neoadjuvant therapies for patients with HR-positive, HER2-negative early-stage breast cancer. Tumours with low MS were unlikely to benefit from NaCT, whereas a high MS predicted resistance to NET. This additional biologic information can aid personalized treatment selection in daily practice and builds a strong rationale to use EndoPredict in biomarker-driven studies in the neoadjuvant setting.

Altered fractionation short-course radiotherapy for stage II-III rectal cancer: a retrospective study

Purpose

To report the long-term outcomes of neoadjuvant altered fractionation short-course radiotherapy in 271 consecutive patients with stage II-III rectal cancer.

Patients and Methods: This was a retrospective single institution study with median follow-up of 101 months (8.4 years). Patients who were alive at the time of analysis in 2018 were contacted to obtain functional outcome data (phone interview). Radiotherapy consisted of 25 Gy in 10 fractions of 2.5 Gy administered twice daily. Median time interval to surgery was 5 days.

Results

Local relapse was observed in 12 patients (4.4%) after a median of 28 months. Overall survival after 5 and 10 years was 73 and 55.5%, respectively (corresponding disease-free survival 65.5 and 51%). Of all patients without permanent stoma, 79% reported no low anterior resection syndrome (LARS; 0–20 points), 9% reported LARS with 21–29 points and 12% serious LARS (30–42 points).

Conclusion

The present radiotherapy regimen was feasible and resulted in low rates of local relapse. Most patients reported good functional outcomes.

Efficacy and safety of the therapeutic cancer vaccine tecemotide (L-BLP25) in early breast cancer: Results from a prospective, randomised, neoadjuvant phase II study (ABCSG 34)

BACKGROUND

Immune-based strategies represent a promising approach in breast cancer (BC) treatment. The glycoprotein mucin-1 (MUC-1) is overexpressed in more than 90% of BC patients, and is targeted by the cancer vaccine tecemotide. We have investigated the efficacy and safety of tecemotide when added to neoadjuvant standard-of-care (SoC) treatment in early BC patients.

PATIENTS AND METHODS

A total of 400 patients with HER2-early BC were recruited into this prospective, multicentre, randomised 2-arm academic phase II trial. Patients received preoperative SoC treatment (chemotherapy or endocrine therapy) with or without tecemotide. Postmenopausal women with oestrogen receptor (ER)+++, or ER++ and Ki67 < 14%, and G1,2 tumours ('luminal A' tumours) received 6 months of letrozole. Postmenopausal patients with triple-negative, ER-/+/++ and Ki67 ≥ 14%, and with G3 tumours, as well as premenopausal patients, received four cycles of epirubicin/cyclophosphamide plus four cycles of docetaxel. Primary end-point was residual cancer burden (RCB; 0/I versus II/III) at surgery. Secondary end-points included pathological complete response (pCR), safety, and quality of life.

FINDINGS

We observed no significant difference in RCB 0/I rates between patients with (36.4%) and without (31.9%) tecemotide in the overall study population (p = 0.40) nor in endocrine and chemotherapy-treated subgroups (25.0% versus 13.3%, p = 0.17; 39.6% versus 37.8%, p = 0.75, respectively). The addition of tecemotide did not affect overall pCR rates (22.5% versus 17.4%, p = 0.23), MUC-1 expression, or tumour-infiltrating lymphocytes content. Tecemotide did not increase toxicity when compared to SoC therapy alone.

INTERPRETATION

Neoadjuvant tecemotide is safe, but does not improve RCB or pCR rates in patients receiving standard neoadjuvant therapy.

MicroRNAs and their role for T stage determination and lymph node metastasis in early colon carcinoma

Worldwide, colon cancer is among the most common cancer entities. Understanding the molecular background is the key to enable accurate stage determination, which is crucial to assess optimal therapy options. The search for preoperative biomarkers is ongoing. In recent years, several studies have proposed a diagnostic and prognostic role for miRNAs in cancer. Aim of this study was to evaluate miRNA expression patterns correlating with tumor stage, especially lymph node metastasis, in primary colon carcinoma tissue. Screening was accomplished using GeneChip^® miRNA v3.0 arrays (Thermo Fisher Scientific, Waltham, MA, USA) and validated via TaqMan^® qPCR assays (Thermo Fisher Scientific, Waltham, MA, USA) to investigate miRNA expressions in 168 FFPE and 83 fresh frozen colon carcinoma samples. Regarding lymph node status, analyses displayed no significantly differential miRNA expression. Interestingly, divergent expression of miR-18a-5p, miR-20a-5p, miR-21-5p, miR-152-3p and miR-1973 was detected in stage pT1. Although miRNAs might not represent reliable biomarkers regarding lymph node metastasis status, they could support risk assessment in stage T1 tumors.

Abstract P6-10-01: Efficacy and safety of the therapeutic cancer vaccine tecemotide (L-BLP25) in early breast cancer: Results from a prospective, randomized, neoadjuvant phase-II study (ABCSG-34)

Background: Immune-based therapeutic strategies represent a promising approach in early and advanced breast cancer treatment. MUC1 glycoprotein is overexpressed and aberrantly glycosylated in over 90% of malignant breast cancer. It is involved in oncogenesis and confers resistance to anti-cancer therapies, thus representing a particularly promising target. Tecemotide is a MUC1-based therapeutic cancer vaccine. The aim of this trial was to investigate the efficacy and safety of preoperative tecemotide in primary breast cancer patients receiving neoadjuvant Standard-of-Care (SoC) treatment.

Patients and Methods: 400 patients with HER2-negative early breast cancer were recruited into this prospective, multicentre randomized 2-arm academic phase-II trial. Patients received preoperative SoC treatment with or without tecemotide therapy. Postmenopausal women with E+++, or E++ and Ki67 &lt;14%, and G1,2,X tumors received 6 months of letrozole as SoC. Postmenopausal patients with triple-negative, E- or E+, or E++ and Ki67 ≥14%, and with G3 tumors, and all premenopausal patients received 4 cycles of epirubicin/cyclophosphamide plus 4 cycles of docetaxel as SoC. Patients were additionally randomized to receive reverse or conventional sequence of epirubicin/cyclophosphamide and docetaxel. Primary endpoint was histopathological response measured by Residual Cancer Burden (RCB0/I vs RCBII/III) at the time of surgery. Secondary endpoints included pCR, efficacy of reverse versus conventional sequence chemotherapy, and safety.

Results: We did not observe a significant difference in RCB0/I rates between patients with (36.4%) and without (31.9%) tecemotide in the overall study population (p = 0.40), and in endocrine and chemotherapy treated subgroups (25.0% vs 13.3%, p = 0.17; 39.6% vs 37.8%, p = 0.75). Similarly, addition of tecemotide did not affect overall pCR rates (22.5% vs 17.4%, p = 0.23). RCB0/I rates were comparable regardless of docetaxel being given before or after epirubicin/cyclophosphamide (37.2% vs 40.1%, p = 0.61). Tecemotide addition was not associated with a worse toxicity profile (178 AEs, 57 SAEs vs 180 AEs, 48 SAEs based on patient incidence).

Conclusion: Immune-based targeting of MUC1 by tecemotide is safe but does not improve RCB and pCR rates in early SoC-treated breast cancer.

Citation Format: Singer CF, Pfeiler G, Hubalek M, Bartsch R, Stoeger H, Pichler A, Petru E, Greil R, Rudas M, Tea M-KM, Wette V, Petzer AL, Sevelda P, Egle D, Dubsky PC, Balic M, Tinchon C, Bago-Horvath Z, Frantal S, Michael G. Efficacy and safety of the therapeutic cancer vaccine tecemotide (L-BLP25) in early breast cancer: Results from a prospective, randomized, neoadjuvant phase-II study (ABCSG-34) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-10-01.

Salvage therapy with high-dose cytarabine and mitoxantrone in combination with all-trans retinoic acid and gemtuzumab ozogamicin in acute myeloid leukemia refractory to first induction therapy

Outcome of patients with primary refractory acute myeloid leukemia remains unsatisfactory. We conducted a prospective phase II clinical trial with gemtuzumab ozogamicin (3 mg/m(2) intravenously on day 1), all-trans retinoic acid (45 mg/m(2) orally on days 4-6 and 15 mg/m(2) orally on days 7-28), high-dose cytarabine (3 g/m(2)/12 h intravenously on days 1-3) and mitoxantrone (12 mg/m(2) intravenously on days 2-3) in 93 patients aged 18-60 years refractory to one cycle of induction therapy. Primary end point of the study was response to therapy; secondary end points included evaluation of toxicities, in particular, rate of sinusoidal obstruction syndrome after allogeneic hematopoietic cell transplantation. Complete remission or complete remission with incomplete blood count recovery was achieved in 47 (51%) and partial remission in 10 (11%) patients resulting in an overall response rate of 61.5%; 33 (35.5%) patients had refractory disease and 3 patients (3%) died. Allogeneic hematopoietic cell transplantation was performed in 71 (76%) patients; 6 of the 71 (8.5%) patients developed moderate or severe sinusoidal obstruction syndrome after transplantation. Four-year overall survival rate was 32% (95% confidence interval 24%-43%). Patients responding to salvage therapy and undergoing allogeneic hematopoietic cell transplantation (n=51) had a 4-year survival rate of 49% (95% confidence intervaI 37%-64%). Patients with fms-like tyrosine kinase internal tandem duplication positive acute myeloid leukemia had a poor outcome despite transplantation. In conclusion, the described regimen is an effective and tolerable salvage therapy for patients who are primary refractory to one cycle of conventional intensive induction therapy. (clinicaltrials.gov identifier: 00143975).

Total body irradiation with volumetric modulated arc therapy: Dosimetric data and first clinical experience

BACKGROUND

To implement total body irradiation (TBI) using volumetric modulated arc therapy (VMAT). We applied the Varian RapidArc™ software to calculate and optimize the dose distribution. Emphasis was placed on applying a homogenous dose to the PTV and on reducing the dose to the lungs.

METHODS

From July 2013 to July 2014 seven patients with leukaemia were planned and treated with a VMAT-based TBI-technique with photon energy of 6 MV. The overall planning target volume (PTV), comprising the whole body, had to be split into 8 segments with a subsequent multi-isocentric planning. In a first step a dose optimization of each single segment was performed. In a second step all these elements were calculated in one overall dose-plan, considering particular constraints and weighting factors, to achieve the final total body dose distribution. The quality assurance comprised the verification of the irradiation plans via ArcCheck™ (Sun Nuclear), followed by in vivo dosimetry via dosimeters (MOSFETs) on the patient.

RESULTS

The time requirements for treatment planning were high: contouring took 5-6 h, optimization and dose calculation 25-30 h and quality assurance 6-8 h. The couch-time per fraction was 2 h on day one, decreasing to around 1.5 h for the following fractions, including patient information, time for arc positioning, patient positioning verification, mounting of the MOSFETs and irradiation. The mean lung dose was decreased to at least 80 % of the planned total body dose and in the central parts to 50 %. In two cases we additionally pursued a dose reduction of 30 to 50 % in a pre-irradiated brain and in renal insufficiency. All high dose areas were outside the lungs and other OARs. The planned dose was in line with the measured dose via MOSFETs: in the axilla the mean difference between calculated and measured dose was 3.6 % (range 1.1-6.8 %), and for the wrist/hip-inguinal region it was 4.3 % (range 1.1-8.1 %).

CONCLUSION

TBI with VMAT provides the benefit of satisfactory dose distribution within the PTV, while selectively reducing the dose to the lungs and, if necessary, in other organs. Planning time, however, is extensive.

Epirubicin and docetaxel with or without capecitabine as neoadjuvant treatment for early breast cancer: final results of a randomized phase III study (ABCSG-24)

BACKGROUND

This randomized phase III trial compared pathologic complete response (pCR) rates of early breast cancer (EBC) following neoadjuvant epirubicin-docetaxel (ED)±capecitabine (C), and evaluated the addition of trastuzumab in HER2-positive tumors.

PATIENTS AND METHODS

Patients with invasive breast cancer (except T4d) were randomly assigned to receive six 3-weekly cycles of ED (both 75 mg/m2)±C (1000 mg/m2, twice daily, days 1-14). Patients with HER2-positive disease were further randomized to receive trastuzumab (8 mg/kg, then 6 mg/kg every 3 weeks) or not. Primary end point: pCR rate at the time of surgery.

RESULTS

Five hundred thirty-six patients were randomized to ED (n=266) or EDC (n=270); 93 patients were further randomized to trastuzumab (n=44) or not (n=49). pCR rate was significantly increased with EDC (23.0% versus 15.4% ED, P=0.027), and nonsignificantly further increased with trastuzumab (38.6% EDC versus 26.5% ED, P=0.212). Rates of axillary node involvement at surgery and breast conservation were improved with EDC versus ED, but not significantly; the addition of trastuzumab had no further impact. Hormone receptor status, tumor size, grade, and C (all P≤0.035) were independent prognostic factors for pCR. Trastuzumab added to ED±C significantly increased the number of serious adverse events (35 versus 18; P=0.020), mainly due to infusion-related reactions.

CONCLUSION

These findings show that the integration of C into a neoadjuvant taxane-/anthracycline-based regimen is a feasible, safe, and effective treatment option, with incorporation of trastuzumab in HER2-positive disease.

CLINICAL TRIAL NUMBER

NCT00309556, www.clinicaltrials.gov.

High-dose imatinib induction followed by standard-dose maintenance in pre-treated chronic phase chronic myeloid leukemia patients--final analysis of a randomized, multicenter, phase III trial

BACKGROUND

Previous data suggest that the response of chronic myeloid leukemia cells to imatinib is dose-dependent. The potential benefit of initial dose intensification of imatinib in pre-treated patients with chronic phase chronic myeloid leukemia remains unknown.

DESIGN AND METHODS

Two hundred and twenty-seven pre-treated patients with chronic myeloid leukemia in chronic phase were randomly assigned to continuous treatment with a standard dose of imatinib (400 mg/day; n=113) or to 6 months of high-dose induction with imatinib (800 mg/day) followed by a standard dose of imatinib as maintenance therapy (n=114).

RESULTS

The rates of major and complete cytogenetic responses were significantly higher in the high-dose arm than in the standard-dose arm at both 3 and 6 months (major cytogenetic responses: 36.8% versus 21.2%, P=0.01 and 50.0% versus 34.5%, P=0.018; complete cytogenetic responses: 22.8% versus 6.2%, P<0.001 and 40.4% versus 16.8%, P<0.001) on the basis of an intention-to-treat analysis. At 12 months, the difference between treatment arms remained statistically significant for complete cytogenetic responses (40.4% versus 24.8%, P=0.012) but not for major cytogenetic responses (49.1% versus 44.2%, P=0.462). The rate of major molecular responses was also significantly better at 3 and 6 months in the high-dose arm (month 3: 14.9% versus 3.5%, P=0.003; month 6: 32.5% versus 8.8%, P<0.001). Overall and progression-free survival rates were comparable between arms, but event-free survival was significantly worse in the high-dose arm (P=0.014).

CONCLUSIONS

Standard-dose imatinib remains the standard of care for pre-treated patients with chronic phase chronic myeloid leukemia (Clinicaltrials.gov identifier: NCT00327262).

Nilotinib as frontline and second-line therapy in chronic myeloid leukemia: open questions

Nilotinib is a second generation ABL tyrosine kinase inhibitor (TKI) that exerts major anti-leukemic effects in newly diagnosed patients with chronic myeloid leukemia (CML) as well as in most patients with imatinib-resistant CML. In freshly diagnosed patients, the anti-leukemic activity of nilotinib exceeds the efficacy of imatinib, and although long-term data for nilotinib are not available yet, the drug has recently been approved for firstline treatment of chronic phase CML in various countries. Still however, several questions concerning the optimal dose, follow-up parameters, long-term safety, and patient selection remain open. Likewise, it remains uncertain whether both Sokal low-risk and high-risk patients should receive nilotinib as frontline therapy in the future. Another question is whether nilotinib can completely eradicate CML in a subset of patients. Furthermore, it remains unclear whether and what comorbidity must be regarded as relative or absolute contra-indication for this TKI. To discuss these issues, the Austrian CML Working Group organized a series of meetings in 2010. In the current article, the outcomes from these discussions are summarized and presented together with recommendations for frontline use of TKIs in various groups of patients with CML. These recommendations should assist in daily practice as well as in the preparation and conduct of clinical trials.

Characterization of a newly identified ETV6-NTRK3 fusion transcript in acute myeloid leukemia

Background

Characterization of novel fusion genes in acute leukemia is important for gaining information about leukemia genesis. We describe the characterization of a new ETV6 fusion gene in acute myeloid leukemia (AML) FAB M0 as a result of an uncommon translocation involving chromosomes 12 and 15.

Methods

The ETV6 locus at 12p13 was shown to be translocated and to constitute the 5' end of the fusion product by ETV6 break apart fluorescence in situ hybridisation (FISH). To identify a fusion partner 3' rapid amplification of cDNA-ends with polymerase chain reaction (RACE PCR) was performed followed by cloning and sequencing.

Results

The NTRK3 gene on chromosome 15 was found to constitute the 3' end of the fusion gene and the underlying ETV6-NTRK3 rearrangement was verified by reverse transcriptase PCR. No RNA of the reciprocal NTRK3-ETV6 fusion gene could be detected.

Conclusion

We have characterized a novel ETV6-NTRK3 fusion transcript which has not been previously described in AML FAB M0 by FISH and RACE PCR. ETV6-NTRK3 rearrangements have been described in secretory breast carcinoma and congenital fibrosarcoma.

High-dose imatinib improves cytogenetic and molecular remissions in patients with pretreated Philadelphia-positive, BCR-ABL-positive chronic phase chronic myeloid leukemia: first results from the randomized CELSG phase III CML 11 "ISTAHIT" study

BACKGROUND

Imatinib 400 mg/day is the standard treatment for patients with chronic phase chronic myeloid leukemia. Recent reports suggested higher and more rapid cytogenetic and molecular responses with higher doses of imatinib.

DESIGN AND METHODS

In this prospective international, multicenter phase III study, 227 patients with pre-treated Philadelphia chromosome-positive, BCR-ABL-positive chronic myeloid leukemia were randomized to a standard-dose imatinib arm (400 mg/day) or a high-dose imatinib arm (800 mg/day for 6 months followed by 400 mg/day as maintenance therapy). In this planned interim analysis hematologic, cytogenetic and molecular responses as well as toxicity were evaluated.

RESULTS

Compared to the standard-dose, high-dose imatinib led to higher rates of major and complete cytogenetic responses at both 3 months (major: 21% versus 37%, P=0.01; complete: 6% versus 25%, P<0.001) and 6 months (major: 34% versus 54%, P=0.009; complete: 20% versus 44%, P<0.001). This was paralleled by a significantly higher major molecular response rate at 6 months in the high-dose imatinib arm (11.8% versus 30.4%; P=0.003). At 12 months, the rates of major cytogenetic response (the primary end-point) were comparable between the two arms (57% versus 59%). In contrast to non-hematologic toxicities, grade 3/4 hematologic toxicities were more common in the high-dose arm. Cumulative complete cytogenetic response rates were higher in patients without dose reduction in the high-dose arm (61%) than in the patients with no dose reduction in the standard-dose arm (36%) (P=0.014).

CONCLUSIONS

This is the first randomized phase III trial in patients with pre-treated chronic phase chronic myeloid leukemia demonstrating improvements in major cytogenetic response, complete cytogenetic response and major molecular response rates with high-dose imatinib therapy (ClinicalTrials.gov Identifier: NCT00327262).

Local relapse after breast-conserving surgery and radiotherapy: effects on survival parameters

PURPOSE

This retrospective analysis of 1,610 women treated for breast cancer and 88 patients with local relapse aims to show the poor survival parameters after local failure and to evaluate risk factors and compare them with other studies and analyses published.

PATIENTS AND METHODS

Between 1984 and 1997, 1,610 patients presenting with a total of 1,635 pT1-2 invasive and noninvasive carcinomas of the breast were treated at the authors' institution. The mean age was 57.1 years (range 25-85 years). Treatment protocols involved breast-conserving surgery with or without systemic therapy and whole-breast radiotherapy in all women, followed by a boost dose to the tumor bed according to risk factors for local recurrence. All axillary node-positive patients underwent systemic therapy (six cycles of classic CMF or tamoxifen 20 mg/day for 2-5 years). The time of diagnosis of local relapse was defined as time 0 for the survival curves after local failure. The association of clinicopathologic factors was studied using uni- and multivariate analyses. Survival and local control were calculated by the Kaplan-Meier actuarial method and significance by the log-rank test.

RESULTS

After a mean follow-up of 104 months, 88 local failures were recorded (5.4%). Calculated from the time of diagnosis of local relapse, 5-year overall survival (OS) was 62.8%, metastasis-free survival 60.6%, and disease-specific survival 64.2%. In patients with failure during the first 5 years after treatment, the survival parameters were worse (OS 50.6%) compared to those who relapsed after 5 years (OS 78.8%; p < 0.028). Significances were also found for initial T- and N-stage and type of failure (solid tumor vs. diffuse spread).

CONCLUSION

This analysis again shows that the survival parameters are worsening after local relapse, especially in case of early occurrence. In breast cancer treatment, therefore, the goal remains to avoid local failure.

Mosaicism due to myeloid lineage–restricted loss of heterozygosity as cause of spontaneous Rh phenotype splitting

Spontaneous Rh phenotype alteration interferes with pretransfusion and prenatal blood group examinations and may potentially indicate hematologic disease. In this study, the molecular background of this biologic phenomenon was investigated. In 9 patients (3 with hematologic disease), routine RhD typing showed a mixture of D-positive and D-negative red cells not attributable to transfusion or hematopoietic stem-cell transplantation. In all patients, congenital and acquired chimerism was excluded by microsatellite analysis. In contrast to D-positive red cells, D-negative subpopulations were also negative for C or E in patients genotyped CcDdee or ccDdEe, respectively, which suggested the presence of erythrocyte precursors with an apparent homozygous cde/cde or hemizygous cde/— genotype. Except for one patient with additional Fyb antigen anomaly, no other blood group systems were affected. RH genotyping of single erythropoietic burst-forming units, combined with microsatellite analysis of blood, different tissues, sorted blood cell subsets, and erythropoietic burst-forming units, indicated myeloid lineage–restricted loss of heterozygosity (LOH) of variable chromosome 1 stretches encompassing the RHD/RHCE gene loci. Fluorescent in situ hybridization studies indicated that LOH was caused by either somatic recombination or deletion. Therefore, most cases of spontaneous Rh phenotype splitting appear to be due to hematopoietic mosaicism based on LOH on chromosome 1.

Impact of natural killer cell dose and donor killer-cell immunoglobulin-like receptor (KIR) genotype on outcome following human leucocyte antigen-identical haematopoietic stem cell transplantation

To define the role of quantitative graft composition and donor killer-cell immunoglobulin-like receptor (KIR) genotype in clinical outcome following unmanipulated peripheral blood stem cell transplantation (PBSCT) from human leucocyte antigen (HLA)-identical siblings, 43 consecutive transplants for haematological malignancies were analysed retrospectively. Twenty-four patients underwent myeloablative conditioning and 19 received busulphan/fludarabine-based reduced intensity conditioning (RIC). In patients with acute myelogenous leukaemia or myelodysplastic syndrome (AML/MDS; n = 18), no relapse occurred following transplants meeting both a high (above median) natural killer (NK) cell count and missing HLA-ligand(s) to donor's KIR(s), compared to all other AML/MDS patients (0% versus 44%; P = 0.049). Missing HLA-B and/or HLA-C ligand combined with missing HLA-A3/11 (KIR3DL2 unblocked) predicted for reduced relapse incidence regardless of diagnosis or conditioning type (P = 0.028). Moreover, in AML/MDS patients, this constellation predicted superior overall survival (OS) (P = 0.046). Transplants with more than two different activating donor KIRs were associated with an increased risk for non-relapse mortality (NRM), both by univariate and multivariate analysis. Quantitative graft composition had a significant impact exclusively in RIC transplants. Here, a trend towards reduced relapse incidence was found in patients receiving high numbers of NK cells (16% versus 54%; P = 0.09). In patients receiving high versus low T cell numbers, OS was superior (83% versus 37%; P = 0.01), due mainly to reduced NRM (0% versus 33%; P = 0.046). By multivariate analysis, relapse risk was decreased significantly in patients receiving high NK cell numbers (P = 0.039). These data suggest that both the number of transplanted NK cells and the donor KIR genotype play a role in graft-versus-malignancy mechanisms in HLA-identical PBSCT.

Suppression of natural killer cells in the presence of CD34+ blood progenitor cells and peripheral blood lymphocytes

Abstract Mobilization of CD34 + peripheral blood progenitor cells (PBPCs) with granulocyte-colony stimulating factor (G-CSF) may induce functional alterations in peripheral blood lymphocyte (PBL) subsets. We and others have shown that natural killer (NK) cells from PBPC collections are less expandable in vitro than those obtained during steady-state hematopoiesis. We show here that the extent of this proliferation deficit is related to the number of circulating CD34 + cells in vivo at the time of PBPC apheresis. Likewise, addition of autologous CD34 + cells to unseparated PBL reduced the expansion of the NK-cell subset by 22.2% +/- 6.0% (n = 10; P <.005). In contrast, when using purified NK cells, their proliferation remained unimpaired by autologous CD34 + cells. Supernatants from CD34 + cells cultured with autologous PBLs had an inhibitory effect on proliferation of purified NK cells (n = 16; P =.03), indicating that an interaction between CD34 + cells and lymphocytes is essential for the suppressive effect on NK cells. To investigate the role of T cells in this interaction, intracellular cytokines were determined in T cells cultured for 7 days with or without autologous CD34 + cells. When cultured with CD34 + cells, the frequency of IL-2-producing CD4 + and CD8 + T cells was reduced by 19% and 24%, respectively, compared with T cells cultured alone (n = 7; P =.016). Interferon-gamma-producing T cells were slightly reduced ( P = not statistically significant [ns]). Finally, the influence of T cells and NK cells on the recovery of myeloid colony-forming cells (CFU-GMs) from purified CD34 + cells was examined. In the presence of T cells, 16% +/- 6% of the input CFU-GM recovered after 7 days, compared with 5% +/- 4% in the presence of NK cells (n = 5; P = ns). Our findings point to an inhibition of NK-cell proliferation mediated by an interaction of CD34 + cells and T cells occurring during PBPC mobilization with G-CSF.

Different subsets of primary chronic myeloid leukemia stem cells engraft immunodeficient mice and produce a model of the human disease

Xenograft models of chronic phase human chronic myeloid leukemia (CML) have been difficult to develop because of the persistence of normal hematopoietic stem cells in most chronic phase CML patients and the lack of methods to selectively isolate the rarer CML stem cells. To circumvent this problem, we first identified nine patients' samples in which the long-term culture-initiating cells were predominantly leukemic and then transplanted cells from these samples into sublethally irradiated NOD/SCID and NOD/SCID-beta2microglobulin-/- mice. This resulted in the consistent and durable (>5 months) repopulation of both host genotypes with similar numbers of BCR-ABL+/Ph+ cells. The regenerated leukemic cells included an initial, transient population derived from CD34+CD38+ cells as well as more sustained populations derived from CD34+CD38- progenitors, indicative of a hierarchy of transplantable leukemic cells. Analysis of the phenotypes produced revealed a reduced output of B-lineage cells, enhanced myelopoiesis with excessive production of erythroid and megakaropoietic cells and the generation of primitive (CD34+) leukemic cells displaying an autocrine IL-3 and G-CSF phenotype, all characteristics of primary CML cells. These findings demonstrate the validity of this xenograft model of chronic phase human CML, which should enable future investigation of disease pathogenesis and new approaches to therapy.

Hematopoietic stem cells in chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a malignant myeloproliferative disorder originating from a pluripotent hematopoietic stem cell that acquires a Philadelphia (Ph) chromosome encoding the BCR-ABL oncogenic fusion protein. This molecular abnormality that is thought to be causative in CML was the first acquired chromosome translocation associated with a human malignancy. This chromosomal translocation also makes it possible to precisely distinguish between residual normal (i.e., Ph-, BCR-ABL-) progenitor or stem cells and their leukemic counterpart, Ph+ or BCR-ABL+ progenitor/stem cells in every given sample of a patient with CML. This has provided seminal insights into the molecular and cellular biology of leukemia and also of the process of normal hematopoiesis. CML has become a fascinating model disease for malignancy in general.

Functional significance of the activation-associated receptors CD25 and CD69 on human NK-cells and NK-like T-cells

The application of autologous ex-vivo expanded cytotoxic lymphocytes to cancer patients may help to control minimal residual disease. However, the number of effector cells and the resulting antitumoral activity that can be generated in vitro are remarkably variable. Thus, we separately assessed the proliferative and cytotoxic potential of CD56+ CD3- natural killer (NK) and CD56+ CD3+ T-cells in relation to their expression of CD25, CD69, and CD16 in vitro. Two-week lymphocyte cultures from peripheral blood (n = 51) and from G-CSF-mobilized progenitor cell harvests (n = 11) were performed repeatedly from 14 women with breast cancer throughout conventional- and high-dose chemotherapy. A large proportion of CD25+ cells on day 7 of the culture predicted high expandability (r = 0.69, p < 0.00001), while elevated expression of CD69 predicted augmented cytotoxicity (r = 0.72; p = 0.00001) and low expandability (r = -0.69, p < 0.00001). CD25 and CD69 expression were inversely correlated (r = -0.8, p < 0.0001). CD16 expression was not suited to predict functional properties. Additionally, NK-cells were sorted by FACS according to CD25 versus CD69 expression. In a [3H]thymidine incorporation assay the CD25+ NK-cell fraction exhibited a higher proliferation rate than did the CD69+ fraction in all of three experiments. Together, our data suggest that CD69 is a useful marker for cytotoxic activity of NK cells, whereas proliferative potential is indicated by CD25 expression. These findings should help optimizing the ex-vivo generation of large numbers of cytotoxic effector cells for immunotherapy.

Expansion of mobilized peripheral blood progenitor cells under defined culture conditions rsing CD34+CD71-CD45- cells as a starting population

A major goal of experimental and clinical hematology is the identification of mechanisms and conditions supporting the expansion of transplantable hematopoietic stem cells. We assessed the expansion potential of CD34+CD71-CD45- cells derived from granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood under recently defined serum-free culture conditions. The CD34+CD71-CD45- cells in mobilized peripheral blood were found to contain the majority (92%+/-5.6) of primitive long-term culture initiating cells (LTCIC) and 53.5%+/-16.7 of the more committed colony-forming cells (CFC). Furthermore, this population represents 23.3%+/-4.1 of the total CD34+ cells and allows reduction of the cell density important for maintenance/expansion of primitive progenitor cells. CD34+ CD71- CD45- cells were cultured in defined serum-free media supplemented with 300 ng each of Flt-3 ligand and stem cell factor (SCF), 60 ng of interleukin (IL)-3, and 20 ng each of IL-6 and G-CSF. Mononuclear cells (MNC) and CFC were expanded 50-fold and 200-fold, respectively; primitive progenitor cells (LTC-IC) were maintained at input values after a total of 10 days of expansion. The addition of IL-15 to our cytokine cocktail expanded LTC-IC 2- to 3-fold and CFC to >500-fold. The data presented should allow clinical manipulation (purging) and expansion procedures with mobilized PBPC harvests without the loss of primitive progenitor cells and could be made applicable for large-scale clinical expansion.

In vivo release of vascular endothelial growth factor from colorectal carcinomas

The formation of new blood vessels is essential for the growth of malignant tumors and their hematogenic spread. Tumor-induced neoangiogenesis occurs through sprouting of preexisting vessels. An alternative mechanism might be the recruitment of bone marrow-derived endothelial cells, or their precursors, to the tumor site by the release of vascular endothelial growth factor (VEGF) from cancer cells, i.e., tumor-induced postnatal vasculogenesis. To investigate if a significant amount of VEGF is released from malignant tumors in vivo, thus potentially mobilizing endothelial precursor cells (EPC) from the bone marrow, we measured plasma levels of soluble VEGF obtained from tumor-draining mesenteric veins (VEGF-M) during surgery and, simultaneously, in venous blood obtained distant from the tumor (VEGF-P). This analysis was performed in 29 patients with colorectal carcinoma. VEGF-M levels were substantially higher in patients with distant metastases (208 +/- 61 pg/ml) compared to patients with nonmetastatic disease (99 +/- 72 pg/ml, p = 0.003). Also, in patients with aggressive disease, i.e., histologically undifferentiated (G3) tumors, higher levels of VEGF-M were measured than in patients with tumors of lower histologic grading (196 +/- 46 vs. 107 +/- 80 pg/ml, p = 0.01). In conclusion, the release of significant amounts of soluble VEGF in vivo from clinically and/or histologically aggressive tumors might reflect their high angiogenic or vasculogenic potential, probably leading to the recruitment of EPC from the bone marrow.

Breaking the rules? X-ray examination of hematopoietic stem cell grafts at international airports

Hematopoietic stem cell grafts from unrelated donors are commonly transported by aircraft. They must not be subjected to x-rays during security checks, which may cause inconvenient discussions between the courier and the airport security staff. We exposed hematopoietic stem cells from mobilized peripheral blood to a widely used x-ray hand-luggage control system. Cell viability as well as growth in vitro of mature progenitor cells (colony-forming cells), primitive progenitor cells (long-term culture-initiating cells), and lymphocytes were not altered even after 10 passages through the hand-luggage control system. Thus, repeated exposure to the low radiation dose of hand-luggage control systems (1.5 +/- 0.6 microSv per exposure) seems to be harmless for hematopoietic stem cells, which should simplify the international transport of stem cell grafts.

Low concentrations of STI571 in the cerebrospinal fluid: a case report

We report a 53-year-old man with lymphoid blast crisis of Ph+ chronic myeloid leukaemia who was treated with STI571, a selective inhibitor of the enzymatic activity of BCR-ABL. He responded excellently to STI571 (600 mg/d), obtaining a complete cytogenetic remission after 3 months of therapy. Although remission in the bone marrow was sustained, the patient developed an isolated central nervous system relapse. Subsequent analyses of STI571 concentrations in the cerebrospinal fluid (CSF) revealed 2-log lower CSF levels of STI571 than corresponding plasma levels. These are the first data demonstrating a low penetration of orally administered STI571 into the CSF in humans.

Ex vivo expansion of long-term culture initiating marrow cells by IL-10, SCF, and IL-3

BACKGROUND

Ex vivo expansion of progentior cells may shorten hematopoietic regeneration after myeloablative chemoradiotherapy, increase target cells for gene therapy, and improve purging of progenitor cell components.

STUDY DESIGN AND METHODS

Marrow cells were incubated for 1 week in suspension culture with and without IL-10, IL-3, and SCF. As long-term culture initiating cells (LTC-ICs) represent early hematopoietic progenitors in vitro, these cells were quantified at initiation and after a 1-week culture period in a limiting dilution assays. Additionally, immunophenotyping of cells before and after culture was performed.

RESULTS

In six experiments, marrow cells cultured for 1 week with IL-10, IL-3, and SCF showed a significant increase (almost doubling) in LTC-ICs as compared with marrow cells before expansion. Additionally, an increased proliferative capacity of LTC-ICs was achieved with a sevenfold increase of committed colony-forming cells and a 10-fold proliferation of high proliferative potential colony-forming cells. Immunophenotyping revealed a sevenfold increase of CD34+ CD45 RA- cells in IL-10-, IL-3-, SCF-stimulated suspension cultures. In unstimulated cultures, no LTC-ICs were maintained after 1 week.

CONCLUSION

Expansion of LTC-ICs by IL-10, IL-3, and SCF has not been shown so far. This in vitro model allows expansion of LTC-IC if compared with the input of progenitor cells without extensive progenitor cell manipulation. This should be an attractive model for in vitro purging, gene transfer, or expansion of progenitor cells to allow rapid engraftment after myeloablative chemotherapy.

High-dose hydroxyurea plus G-CSF mobilize BCR-ABL-negative progenitor cells (CFC, LTC-IC) into the blood of newly diagnosed CML patients at any time of hematopoietic regeneration

The objective of this study was to analyze the mobilization kinetics of normal (BCR-ABL(neg)) and malignant (BCR-ABL(pos)) progenitor cells using a new, low toxic, out-patient-based mobilization regimen for Philadelphia chromosome-positive (Ph(pos)) chronic myelogenous leukemia (CML) patients. High doses of hydroxyurea (HD-HU, 3.5 g/m(2) per day, orally for 7 days) followed by granulocyte colony-stimulating factor (G-CSF) (10 microg/kg subcutaneously) were administered to 11 newly diagnosed CML patients. Each apheresis product (n = 30) was individually analyzed for the number and genotype of mature colony-forming cells (CFC) and primitive long-term culture initiating cells (LTC-IC), respectively, by reverse transcription polymerase chain reaction (RT-PCR) of individual colonies. Sufficient numbers of CD34(+) cells/kg bodyweight (BW) could easily be obtained in all patients (median, 15 x 10(6)/kg BW per patient) with a median number of three aphereses performed per patient (range 2-4). Almost each apheresis itself (25/30) contained > or =2 x 10(6) CD34(+) cells/kg BW. All patients with low and intermediate Sokal risk indices (9/11) mobilized primarily BCR-ABL(neg) LTC-IC (median 92%, range 47-100) and CFC (median 89%, range 57-100). Moreover, the mean percentage of BCR-ABL(neg) CFC and LTC-IC in the various apheresis products in these patients did not change throughout the entire time of hematopoietic regeneration. The toxicity of the mobilization procedure was low. Side effects were mild erythema in 8/11 and oral mucositis in 3/11 patients. Overall, the low toxicity of this regimen, together with the fact that sufficient BCR-ABL(neg) progenitors can be collected throughout the entire period of hematopoietic regeneration, renders this mobilization regimen particularly attractive for the collection of BCR-ABL(neg) progenitors in early chronic phase of Ph(pos) CML.

Optimal timing for the collection and in vitro expansion of cytotoxic CD56(+) lymphocytes from patients undergoing autologous peripheral blood stem cell transplantation

To identify the optimal time for the collection of CD56(+) cytotoxic lymphocytes for adoptive immunotherapy in patients undergoing high-dose chemotherapy (HDCT) and peripheral blood stem cell (PBSC) transplantation, 18 breast cancer patients receiving either three cycles of epirubicin/paclitaxel (CT x 3) followed by HDCT and PBSC transplantation (n = 12) or CTx6 (n = 6) were studied. Blood samples were obtained before each CT/HDCT cycle, from PBSC collections, and repeatedly after autografting for up to 12 months. The number of CD56(+)3(-) and CD56(+)3(+) lymphocytes, their in vitro expandability with interleukin-2, and their cytotoxicity against MCF-7 and Daudi cells were analyzed. Six healthy females served as controls. CD56(+) cell counts in both treatment groups were subnormal but stable during the observation period. The cytotoxicity of the expanded CD56(+) cells was normal and unaffected by the treatment. The in vitro CD56(+) cell expandability (controls, 100 +/- 31-fold, mean +/- SEM) was normal before CT1 and CT2, but reduced in PBSC harvests performed after CT2 and application of G-CSF (21 +/- 6-fold; p < 0.01). After PBSC harvesting, the CD56(+) cell expandability increased to 185 +/- 74-fold and 170 +/- 69-fold (before CT3 and HDCT). This increase was not observed in those patients who did not undergo PBSC mobilization. Two weeks after autografting, the CD56(+) cell expandability was minimal (6 +/- 1-fold), and recovered to 34 +/- 6-fold. Thus, CT, HDCT and autografting do not alter the frequency and inducible cytotoxicity of CD56(+) cells in breast cancer patients. However, the proliferative capacity of CD56(+) cells obtained from PBSC harvests and after autografting is impaired. Therefore, instead of the PBSC graft, maximally expandable CD56(+) cells obtained at least 1 week after PBSC collection should be considered for adoptive immunotherapy after PBSC autografting.

Hematopoietic stem cells

The adequate production of blood cells is maintained by a set of immature hematopoietic stem cells (HSC) located in the bone marrow after birth. HSC are able to reconstitute the hematopoietic system in disease-related bone marrow failure and bone marrow aplasia. Nowadays, HSC cells can be mobilized from the bone marrow into the peripheral blood using hematopoietic cytokines, allowing a convenient harvest of these cells for clinical transplantation. This review outlines the development of the hematopoietic system in the embryo and in adults and the characterization, enumeration, purification and ex vivo expansion of HSC for clinical use. Future directions include the genetic manipulation of HSC and the identification/expansion of bone marrow-derived stem cells capable of generating non-hematopoietic tissues.

Candida ciferrii, a new fluconazole-resistant yeast causing systemic mycosis in immunocompromised patients

Systemic infections related to fluconazole-resistant yeasts are increasingly observed in immunocompromised patients receiving fluconazole as a prophylactic antifungal treatment. Here, we report a case of invasive candidiasis caused by Candida ciferrii in a patient with acute myeloid leukemia and who suffered a relapse after autologous peripheral blood progenitor cell transplantation. Erythematous skin papulae and spotted pulmonary infiltrations were present. A skin biopsy led to the diagnosis of invasive candidiasis, emphasizing the diagnostic usefulness of this procedure. The yeast was identified as Candida ciferrii and in vitro susceptibility testing revealed its resistance to fluconazole. Until now, Candida ciferrii has not been known to cause invasive fungal infections in humans. Thus, we add another fungus to the list of flucanozole-resistant yeasts and suggest that in vitro susceptibility testing of isolated fungi should be performed for the selection of appropriate antimycotic drugs.

Differences between normal and CML stem cells: potential targets for clinical exploitation

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder in which there is a deregulated amplification of CML progenitors at intermediate stages of their differentiation along the myeloid, erythroid and megakaryocyte pathways. Such cell populations are routinely quantified using standard in vitro colony-forming cell (CFC) assays. The excessive production of leukemic CFC that is seen in most CML patients at diagnosis may be explained at least in part by their increased proliferative activity. An anomalous cycling behavior in vivo has also been found to extend to more primitive CML progenitor populations detectable as long-term culture-initiating cells (LTC-IC). Although the molecular basis of these changes in CML progenitor regulation is not fully understood at the level of the primitive CFC compartment, a selective inability of CML progenitors to be inhibited by certain -C-C-type chemokines has been demonstrated. Failure of the CML stem cell compartment to expand in vivo at the same rate as later progenitor cell types may be explained by their unique additional possession of an intrinsically upregulated probability of differentiation. Such a mechanism would be consistent with the observed loss of LTC-IC activity by CML cells incubated in vitro under conditions that sustain or expand normal LTC-IC populations. Initial clinical studies undertaken at our center established the feasibility of exploiting the differential behavior of primitive normal and CML cells in vitro as a potential purging strategy for reducing the leukemic stem cell content of CML marrow autografts. The results of a larger, second trial now in progress on a group of unselected patients are encouraging. Future studies of nonobese diabetic/severe-combined immunodeficiency mice engrafted with CML cells should provide another useful preclinical model for evaluating treatments that may more effectively eradicate the neoplastic clone in vivo.

Evidence from a leukaemia model for maintenance of vascular endothelium by bone-marrow-derived endothelial cells

BACKGROUND

Vascular endothelial cells lost from the blood-vessel endothelium through necrosis or apoptosis must be replaced. We investigated in a leukaemia model whether bone-marrow-derived endothelial cells contribute to this maintenance angiogenesis.

METHODS

We studied six patients with chronic myelogenous leukaemia (CML) carrying the BCR/ABL fusion gene in their bone-marrow-derived cells. We screened endothelial cells generated in vitro from bone-marrow-derived progenitor cells and vascular endothelium in myocardial tissue for the BCR/ABL fusion gene by in-situ hybridisation. For detection of donor-type endothelial cells after transplantation of haemopoietic stem cells, recipient tissue was stained with monoclonal antibodies against donor-type HLA antigens.

FINDINGS

We identified the BCR/ABL fusion gene in variable proportions (0-56%) of endothelial cells generated in vitro. Endothelial cells expressing the fusion gene were found in the vascular endothelium of a patient. In a recipient of an allogeneic stem-cell transplant, normal donor-type endothelial cells were detected in the vascular endothelium.

INTERPRETATION

These findings suggest that CML is not solely a haematological disease but originates from a bone-marrow-derived haemangioblastic precursor cell that can give rise to both blood cells and endothelial cells. Moreover, normal bone-marrow-derived endothelial cells can contribute to the maintenance of the blood vascular endothelium. The integration of bone-marrow-derived endothelial cells into the vascular endothelium provides a rationale for developing vascular targeting strategies in vasculopathies, inflammatory diseases, and cancer.

Evaluation of optimal survival of primitive progenitor cells (LTC-IC) from PBPC apheresis products after overnight storage

Optimal overnight (ON) storage of PBPC aphereses is becoming an increasingly important issue and different options for storing PBPC products exist. The survival of primitive progenitor cells is of major interest, as recent data suggest that these progenitors are not only important for long-term engraftment but also contribute significantly to the early phase of hematopoietic engraftment after myeloablative therapy. We therefore investigated the survival of primitive progenitor cells (ie long-term culture initiating cells, LTC-IC) before (ie within 2 h after finishing the apheresis procedure) and after ON storage lasting 16 to 20 h. In addition, we compared the % of recovery of LTC-IC with that of mature progenitors (ie colony-forming cells, CFC) and with the % viability of the mononuclear cells in the apheresis product. Aliquots of PBPC aphereses products were tested in collection bags at room temperature (RT), in EDTA tubes both at RT or 4 degrees C +/- the addition of autologous plasma (AP; 2.6-fold the apheresis volume) and +/- the possibility of gas exchange. Mean viable cell counts did not show strong differences between the different storage conditions and were poor predictors for the survival of CFC and LTC-IC. At RT (collection bags, EDTA tubes +/- gas exchange) recoveries (% of input) of both, CFC (18%, 18% and 31%) and LTC-IC (10%, 4%, 17%) were low. The addition of AP at RT improved the survival of CFC and LTC-IC to 66% and 38%, respectively. Optimal recoveries for both types of progenitors (CFC: 99%, LTC-IC: 109%) were obtained at 4 degrees C in the presence of AP. In addition, a good correlation between the survival of CFC and LTC-IC was obtained (r = 0.76) suggesting that the analysis of CFC may also allow some conclusions to be drawn on the survival of LTC-IC. Bone Marrow Transplantation (2000) 25, 197-200.

Aspergillus osteoarthritis in acute lymphoblastic leukemia

We report an unusual case of arthritis of the right wrist due to Aspergillus fumigatus without evidence for a generalized infection, following chemotherapy for acute lymphoblastic leukemia. The diagnosis was made by surgical biopsy. Amphotericin-B (Am-B) was not tolerated by the patient. Liposomal preparations of Am-B penetrate poorly into bone and cartilage. Therefore, oral itraconazole was given; the arthritis improved and chemotherapy was continued without infectious complications. Two weeks after complete hematopoietic recovery, an intracranial hemorrhage from a mycotic aneurysm of a brain vessel occurred, although the patient was still receiving itraconazole. We emphasize the importance of prompt and thorough efforts to identify the causative agent in immunocompromised patients with a joint infection. Itraconazole is effective in Aspergillus osteoarthritis but, due to its poor penetration into the brain, the combination with a liposomal formulation of Am-B is recommended.