Anne Flörcken

Can Tyrosine Kinase Inhibitors be Discontinued in Patients with Metastatic Renal Cell Carcinoma and a Complete Response to Treatment? A Multicentre, Retrospective Analysis

BACKGROUND Discontinuation of treatment with tyrosine kinase inhibitors (TKIs) and readministration in case of recurrence could improve quality of life (QoL) and reduce treatment costs for patients with metastatic renal cell carcinoma (mRCC) in which a complete remission (CR) is achieved by medical treatment alone or with additional resection of residual metastases. OBJECTIVE To evaluate whether TKIs can be discontinued in these selected patients with mRCC. DESIGN, SETTING, AND PARTICIPANTS A retrospective analysis of medical records and imaging studies was performed on all patients with mRCC treated with TKIs (n=266) in five institutions. Patients with a CR under TKI treatment alone or with additional metastasectomy of residual disease following a partial response (PR), in which TKIs were discontinued, were included in the analysis. Outcome criteria analysed were time to recurrence of previous metastases, occurrence of new metastases, symptomatic progression, improvement of adverse events, and response to reexposure to TKIs. INTERVENTIONS Sunitinib 50mg/day for 4 wk on and 2 wk off, sorafenib 800mg/day. MEASUREMENTS Response according to Response Evaluation Criteria in Solid Tumours (RECIST). RESULTS AND LIMITATIONS We identified 12 cases: 5 CRs with sunitinib, 1 CR with sorafenib, and 6 surgical CRs with sunitinib followed by residual metastasectomy. Side-effects subsided in all patients off treatment. At a median follow-up of 8.5 mo (range: 4-25) from TKI discontinuation, 7 of 12 patients remained without recurrence and 5 had recurrent disease, with new metastases in 3 cases. Median time to progression was 6 mo (range: 3-8). Readministration of TKI was effective in all cases. The study is limited by small numbers and retrospective design. CONCLUSIONS Discontinuation of TKI in patients with mRCC and CR carries the risk of progression with new metastases and potential complications. Further investigation in a larger cohort of patients is warranted before such an approach can be regarded as safe.

SWITCH: A Randomised, Sequential, Open-label Study to Evaluate the Efficacy and Safety of Sorafenib-sunitinib Versus Sunitinib-sorafenib in the Treatment of Metastatic Renal Cell Cancer

BACKGROUND Understanding how to sequence targeted therapies for metastatic renal cell carcinoma (mRCC) is important for maximisation of clinical benefit. OBJECTIVES To prospectively evaluate sequential use of the multikinase inhibitors sorafenib followed by sunitinib (So-Su) versus sunitinib followed by sorafenib (Su-So) in patients with mRCC. DESIGN, SETTING, AND PARTICIPANTS The multicentre, randomised, open-label, phase 3 SWITCH study assessed So-Su versus Su-So in patients with mRCC without prior systemic therapy, and stratified by Memorial Sloan Kettering Cancer Center risk score (favourable or intermediate). INTERVENTION Patients were randomised to sorafenib 400mg twice daily followed, on progression or intolerable toxicity, by sunitinib 50mg once daily (4 wk on, 2 wk off) (So-Su), or vice versa (Su-So). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The primary endpoint was improvement in progression-free survival (PFS) with So-Su versus Su-So, assessed from randomisation to progression or death during second-line therapy. Secondary endpoints included overall survival (OS) and safety. RESULTS AND LIMITATIONS In total, 365 patients were randomised (So-Su, n=182; Su-So, n=183). There was no significant difference in total PFS between So-Su and Su-So (median 12.5 vs 14.9 mo; hazard ratio [HR] 1.01; 90% confidence interval [CI] 0.81-1.27; p=0.5 for superiority). OS was similar for So-Su and Su-So (median 31.5 and 30.2 mo; HR 1.00, 90% CI 0.77-1.30; p=0.5 for superiority). More So-Su patients than Su-So patients reached protocol-defined second-line therapy (57% vs 42%). Overall, adverse event rates were generally similar between the treatment arms. The most frequent any-grade treatment-emergent first-line adverse events were diarrhoea (54%) and hand-foot skin reaction (39%) for sorafenib; and diarrhoea (40%) and fatigue (40%) for sunitinib. CONCLUSIONS Total PFS was not superior with So-Su versus Su-So. These results demonstrate that sorafenib followed by sunitinib and vice versa provide similar clinical benefit in mRCC. PATIENT SUMMARY We investigated if total progression-free survival (PFS) is improved in patients with advanced/metastatic kidney cancer who are treated with sorafenib and then with sunitinib (So-Su), compared with sunitinib and then sorafenib (Su-So). We found that total PFS was not improved with So-Su compared with Su-So, but both treatment options were similarly effective in patients with advanced/metastatic kidney cancer. TRIAL REGISTRATION ClinicalTrials.gov identifier NCT00732914, www.clinicaltrials.gov.

Outcome of treatment discontinuation in patients with metastatic renal cell carcinoma and no evidence of disease following targeted therapy with or without metastasectomy

BACKGROUND It is unknown if discontinuation of targeted therapy (TT) and readministration in case of recurrence is feasible in patients with metastatic renal cell carcinoma (mRCC) in which complete response (CR) is achieved by TT alone or no evidence of disease (NED) with additional resection of residual metastases. PATIENTS AND METHODS Patients in whom TT was discontinued after CR to TT alone or NED after additional metastasectomy were included in this retrospective analysis. Outcome criteria evaluated were time off TT, recurrence of metastases and response to re-exposure to TT. Univariate and multivariate analyses were carried out to identify variables potentially predictive of outcome. RESULTS In 36 patients with CR or NED under TT with sunitinib (22), sorafenib (11), bevacizumab/interferon (2) and temsirolimus (1), TT was discontinued. Recurrence was observed in 24 patients (66.7%). Re-exposure to TT was effective in 86.9% of these cases. Twelve patients (33.3%) remained recurrence free at a median follow-up of 12 months (range 3-31). Median time off TT was 7 months (range 1-31). Factors that correlate with outcome could not be identified. CONCLUSIONS In the majority of patients with mRCC and CR or NED, discontinuation of TT was followed by recurrence, but re-exposure to TT was effective.

Sex Differences in the Drug Therapy for Oncologic Diseases

There are clear gender-dependent differences in response rates and the probability of side effects in patients treated with chemotherapy. Sex-biased expression levels of metabolic enzymes and transporters in liver and kidney leading to different pharmacokinetics have been described for most common anti-cancer drugs. In women, half-life is often longer, which is associated with improved survival, but also increased toxicity.Some chemotherapy protocols lead to a better response rate in women without increasing toxicity (e.g., cisplatin and irinotecan), while others only increase toxicity, but do not improve response rates in women (e.g., 5-fluorouracil). The increased toxicity often correlates with different pharmacokinetics, but women also show a higher sensitivity to some agents with shorter half-life (e.g., steroids). Organ-specific toxicities like cardiac toxicity after doxorubicin treatment or neurotoxicity associated with ifosfamide are more severe in women due to gender-specific changes in gene expression. Novel therapies like tyrosine kinase inhibitors or monoclonal antibodies show very complex, but clinical significant differences depending on gender. Antibodies often have a longer half-life in women, which is associated with an improved response to therapy.Side effects appear to be highly dependent on different tissue properties, as women have a higher incidence of oral mucositis, but lower rates of gut toxicity. Nausea and vomiting is a greater problem in females during therapy due to the lower activity of anti-emetic drugs. Nausea and vomiting pose a bigger challenge in female patients, as anti-emetic drugs seem to be less effective.

Allogeneic gene-modified tumor cells (RCC-26/IL-7/CD80) as a vaccine in patients with metastatic renal cell cancer: a clinical phase-I study

Despite novel targeted agents, prognosis of metastatic renal cell cancer (RCC) remains poor, and experimental therapeutic strategies are warranted. Transfection of tumor cells with co-stimulatory molecules and/or cytokines is able to increase immunogenicity. Therefore, in our clinical study, 10 human leukocyte antigen (HLA)-A*0201+ patients with histologically-confirmed progressive metastatic clear cell RCC were immunized repetitively over 22 weeks with 2.5–40 × 106 interleukin (IL)-7/CD80 cotransfected allogeneic HLA-A*0201+ tumor cells (RCC26/IL-7/CD80). Endpoints of the study were feasibility, safety, immunological and clinical responses. Vaccination was feasible and safe. In all, 50% of the patients showed stable disease throughout the study; the median time to progression was 18 weeks. However, vaccination with allogeneic RCC26/IL-7/CD80 tumor cells was not able to induce TH1-polarized immune responses. A TH2 cytokine profile with increasing amounts of antigen-specific IL-10 secretion was observed in most of the responding patients. Interferon-γ secretion by patient lymphocytes upon antigen-specific and non-specific stimulation was substantially impaired, both before and during vaccination, as compared with healthy controls. This is possibly due to profound tumor-induced immunosuppression, which may prevent induction of antitumor immune responses by the gene-modified vaccine. Vaccination in minimal residual disease with concurrent depletion of regulatory cells might be one strategy to overcome this limitation.

BCAT1 restricts αKG levels in AML stem cells leading to IDHmut-like DNA hypermethylation

The branched-chain amino acid (BCAA) pathway and high levels of BCAA transaminase 1 (BCAT1) have recently been associated with aggressiveness in several cancer entities. However, the mechanistic role of BCAT1 in this process remains largely uncertain. Here, by performing high-resolution proteomic analysis of human acute myeloid leukaemia (AML) stem-cell and non-stem-cell populations, we find the BCAA pathway enriched and BCAT1 protein and transcripts overexpressed in leukaemia stem cells. We show that BCAT1, which transfers α-amino groups from BCAAs to α-ketoglutarate (αKG), is a critical regulator of intracellular αKG homeostasis. Further to its role in the tricarboxylic acid cycle, αKG is an essential cofactor for αKG-dependent dioxygenases such as Egl-9 family hypoxia inducible factor 1 (EGLN1) and the ten-eleven translocation (TET) family of DNA demethylases. Knockdown of BCAT1 in leukaemia cells caused accumulation of αKG, leading to EGLN1-mediated HIF1α protein degradation. This resulted in a growth and survival defect and abrogated leukaemia-initiating potential. By contrast, overexpression of BCAT1 in leukaemia cells decreased intracellular αKG levels and caused DNA hypermethylation through altered TET activity. AML with high levels of BCAT1 (BCAT1high) displayed a DNA hypermethylation phenotype similar to cases carrying a mutant isocitrate dehydrogenase (IDHmut), in which TET2 is inhibited by the oncometabolite 2-hydroxyglutarate. High levels of BCAT1 strongly correlate with shorter overall survival in IDHWTTET2WT, but not IDHmut or TET2mut AML. Gene sets characteristic for IDHmut AML were enriched in samples from patients with an IDHWTTET2WTBCAT1high status. BCAT1high AML showed robust enrichment for leukaemia stem-cell signatures, and paired sample analysis showed a significant increase in BCAT1 levels upon disease relapse. In summary, by limiting intracellular αKG, BCAT1 links BCAA catabolism to HIF1α stability and regulation of the epigenomic landscape, mimicking the effects of IDH mutations. Our results suggest the BCAA–BCAT1–αKG pathway as a therapeutic target to compromise leukaemia stem-cell function in patients with IDHWTTET2WT AML.

Allogeneic partially HLA-matched dendritic cells pulsed with autologous tumor cell lysate as a vaccine in metastatic renal cell cancer: A clinical phase I/II study

Multi-kinase inhibitors have been established for the treatment of advanced renal cell cancer, but long-term results are still disappointing and immunotherapeutic approaches remain an interesting experimental option particularly in patients with a low tumor burden. DC are crucial for antigen-specific MHC-restricted T cell immunity. Furthermore, allogeneic HLA-molecules pose a strong immunogenic signal and may help to induce tumor-specific T cell responses. In this phase I/II trial, 7 patients with histologically confirmed progressive metastatic RCC were immunized repetitively with 1 × 107 allogeneic partially HLA-matched DC pulsed with autologous tumor lysate following a schedule of 8 vaccinations over 20 weeks. Patients also received 3 Mio IE IL-2 s.c. once daily starting in week 4. Primary endpoints of the study were feasibility and safety. Secondary endpoints were immunological and clinical responses. Vaccination was feasible and safe with no severe toxicity being observed. No objective response could be documented. However, while all patients had documented progress at study entry, 29% of the patients showed SD throughout the study with a mean TTP of 24.6 weeks (range 5 to 96 weeks). In 3/7 patients, TH1-polarized immune responses against RCC-associated antigens were observed. In one patient showing a minimal clinical response and a TTP of 96 weeks, clonally proliferated T cells against yet undefined antigens were induced by the vaccine. Vaccination with tumor antigen loaded DC remains an interesting experimental approach, but should rather be applied in the situation of minimal residual disease after systemic therapy. Additional depletion of regulatory cells might be a promising strategy.

Myeloid-derived suppressor cells in human peripheral blood: optimized quantification in healthy donors and patients with metastatic renal cell carcinoma

Induction of myeloid-derived suppressor cells is an important mechanism leading to tolerance against tumors. Phenotypic characterization of MDSC has been established and heterogeneous populations with monocytic or granulocytic features have been characterized. Increased levels of MDSC have been described in metastatic renal cell carcinoma and seem to correlate with an adverse outcome. As MDSC constitute only small populations in peripheral blood of cancer patients, it is highly important to achieve technically optimized conditions for quantification. Different cell preparation techniques--besides freezing and thawing--are potential sources of substantial variation. Our study was focused on an optimized quantification of MDSC in pB of healthy donors and patients with mRCC, in whom major technical sources of variation were analyzed. Whole blood and peripheral blood mononuclear cells were used for the flow cytometric quantification of MDSC in the pB of mRCC patients and healthy donors. We compared (1) analysis in whole blood vs. PBMC after Ficoll gradient centrifugation and (2) immediate analysis after blood drawing vs. analysis one day later. Finally, in order to evaluate our optimized technical approach, pB of 15 patients with histologically confirmed mRCC under treatment with either sunitinib or sorafenib was analyzed. No difference in the number of MDSC was observed after analysis in whole blood vs. PBMC. In contrast, the time point of analysis was a source of substantial variation (one day later vs. immediate analysis after blood drawing). In conclusion, for optimal analysis of MDSC, immediate analysis of whole blood after blood drawing rather than one day later seems to be most appropriate under the aspect of practical feasibility and reliability. Using this method, we were able to confirm both (a) increased numbers of MDSC in patients with mRCC and (b) a decrease of MDSC under sunitinib therapy.

Peripheral blood sCD3− CD4+ T cells: a useful diagnostic tool in angioimmunoblastic T cell lymphoma

Angioimmunoblastic T cell lymphoma (AITL) belongs to the subgroup of mature T cell lymphomas according to the World Health Organization and is one of the common T cell lymphomas in Western countries. Particularly in cases in which histological confirmation cannot be easily achieved, immunophenotyping of peripheral blood can give important information for the differential diagnosis of AITL. sCD3− CD4+ T cells are a typical feature of AILT in flow cytometry of peripheral blood. In this retrospective study, the diagnostic value of flow cytometry for the diagnosis ‘AITL’ was assessed by comparing the frequency of sCD3− CD4+ T cells in leukemic AITL patients and in patients with other leukemic CD4+ T cell lymphomas. Immunophenotyping of peripheral blood by flow cytometry was performed in a lymphocyte gate using fluorochrome‐labelled antibodies against CD3, CD2, CD4, CD5, CD7, CD8, CD10, CD14, CD16, CD19, CD56, CD57 and T cell receptor. In 17/17 leukemic AITL patients, a small but distinct population of sCD3− CD4+ T cells was detected (mean percentage of sCD3− CD4+ T cells in the lymphocyte gate: 11.9 ± 15.4%, range 0.1–51.8%). In contrast, sCD3− CD4+ T cells were found in only 1/40 patients with other leukemic CD4+ T cell lymphomas (one patient with mycosis fungoides). sCD3− CD4+ T cells have a high positive predictive value (94%) for the diagnosis ‘AITL’. Flow cytometry is particularly useful in the differential diagnosis of AITL, even if the aberrant T cell population has a very low frequency. Further biological characterization of this subfraction of lymphoma cells is warranted. Copyright

Gene expression profiling of peripheral blood mononuclear cells during treatment with a gene-modified allogeneic tumor cell vaccine in advanced renal cell cancer: tumor-induced immunosuppression and a possible role for NF-κB.

Tumor‐induced immunosuppression remains a major challenge for immunotherapy of cancer patients. To further elucidate why an allogeneic gene‐modified [interleukin‐7 (IL‐7)/CD80‐cotransfected] renal cell cancer (RCC) vaccine failed to induce clinically relevant TH‐1‐polarized immune responses, peripheral blood mononuclear cells from enrolled study patients were analyzed by gene expression profiling (GEP) both prior and after vaccination. At baseline before vaccination, a profound downregulation of gene signatures associated with antigen presentation, immune response/T cells, cytokines/chemokines and signaling/transcription factors was observed in RCC patients as compared to healthy controls. Vaccination led to a partial reversion of preexisting immunosuppression, however, GEP indicated that an appropriate TH‐1 polarization could not be achieved. Most interestingly, our results suggest that the nuclear factor‐kappa B signaling pathway might be involved in the impairment of immunological responsiveness and the observed TH‐2 deviation. In summary, our data suggest that GEP might be a powerful tool for the prediction of immunosuppression and the monitoring of immune responses within immunotherapy trials.