Sven Hanson

The sensory nervous system in the vertebrate head arises from two different cell populations: neural crest and placodal cells. By contrast, in the trunk it originates from neural crest only. How do placode precursors become restricted exclusively to the head and how do multipotent ectodermal cells make the decision to become placodes or neural crest? At neural plate stages, future placode cells are confined to a narrow band in the head ectoderm, the pre-placodal region (PPR). Here, we identify the head mesoderm as the source of PPR inducing signals, reinforced by factors from the neural plate. We show that several independent signals are needed: attenuation of BMP and WNT is required for PPR formation. Together with activation of the FGF pathway, BMP and WNT antagonists can induce the PPR in naïve ectoderm. We also show that WNT signalling plays a crucial role in restricting placode formation to the head. Finally, we demonstrate that the decision of multipotent cells to become placode or neural crest precursors is mediated by WNT proteins: activation of the WNT pathway promotes the generation of neural crest at the expense of placodes. This mechanism explains how the placode territory becomes confined to the head, and how neural crest and placode fates diversify.

BACKGROUND: Imatinib is a tyrosine kinase inhibitor of BCR-ABL, ABL, PDGFR-α and -β, KIT, and DDR. In solid tumors, it inhibits proliferation and invasiveness and facilitates higher intratumoral cytotoxic drug concentrations. Vinorelbine has good tolerability and efficacy in metastatic breast cancer (MBC). This study evaluates the safety and efficacy of imatinib and vinorelbine in combination. METHODS: In a prospective, open-label, phase I/II trial, 400 mg imatinib p.o. daily (corrected from 600 mg) was combined with an escalating dose of vinorelbine i.v. weekly in four dose levels of 10, 15, 20, and 25 mg/m(2) (each n ≥ 5) to treat patients with MBC (expressing PDGFR-α and/or -β, and/or KIT). The last patient of each level was treated for >28 days, before enrolment for the next dose level started. Study endpoints were feasibility and tolerability, incidence of hematological and nonhematological toxicity, and clinical efficacy (data cutoff: November 18, 2011). A total of 33 patients have been enrolled, and all dose levels have been fully recruited. One patient is still on study medication. A translational subprotocol is ongoing. RESULTS: All 33 included patients are evaluable for safety (32 within the ITT population). Eleven patients were excluded early from the study (progressive disease, toxicity, and withdrawal of consent). Twenty-two patients participated in the study for >28 days ('ITT >28'). Within the ITT population, the response rate [complete response (CR) and partial response (PR)] was 9.4% (n = 3), the clinical benefit rate (CBR; CR+PR+stable disease) 50% (n = 16), and the median time to progression (TTP) 155 days. A total of 21.3% of the patients were on study medication for >6 months, and 15.2% for >12 months (mean 140 days, range 15-643). Within 'ITT >28', the response rate was 13.6%, CBR 72.7%, and median TTP 176 days. The response was independent of the receptor status (PDGFR-α, -β, and KIT). Toxicities were as follows (safety population): 21.6% severe leukopenia, 9.1% severe neutropenia (with 1 febrile neutropenia), 1 case of bowel perforation, 36% diarrhea (3% severe), 84.8% nausea (severe 15.2%), 48.5% vomiting (severe 9.1%), 27.3% infections (severe 6.1%), 12.1% peripheral neuropathy (severe 9.1%), and 36.4% dyspnea (3% severe). Four patients on trial died (nondrug-related). CONCLUSION: The combination of imatinib and vinorelbine in MBC appeared to be feasible and tolerable. A CBR of 50% (ITT) in pretreated patients suggests that this combination may be active. Although toxicities were frequent, they appeared to be manageable.

1061 Background: BRAWO is a German non-interventional study, which enrolled more than 2400 patients (pts) with advanced/metastatic, hormone-receptor-positive and HER2-negative breast cancer treated with EVE and EXE. Main objectives are a) the impact of physical activity on efficacy and quality of life, b) prophylaxis and management of stomatitis in clinical routine, and c) the sequence of therapy when EVE is used in daily clinical practice. Methods: In this update on the results of the 3rd interim analysis (data cut-off 18-Oct-2016) we analyzed under real world conditions the first 1.078 patients followed up until disease progression for their progression-free survival (PFS) events. A two-stage process based on a Cox regression model was used to check the relevance of the start dose on PFS. In the first step potentially relevant covariates defined by medical experts were evaluated for relevance. In the second step start dose and all covariates showing a p-value of at most 0.1 in first step including all two-interaction of start dose with these parameters were included into the model. Results: Our multivariate analysis support the evidence that predictive factors, such as body mass index (BMI, p-value: < 0.001), therapeutic line (1st vs. 2nd+3rd vs. ≥4th; p-value: 0.013), presence of visceral metastases (p-value: < 0.001) and ECOG (Eastern Cooperative Oncology Group, p-value: < 0.001) status at the beginning of the therapy correlated significantly with the PFS. 283 patients started with 5mg and 795 Patients started with 10 mg. Starting dose had no significant impact on the PFS (neither as main effect nor within interactions, p-value: 0.44-0.88). Conclusions: Even though the approved and recommended starting dose for treatment with EVE is 10 mg, physicians sometimes start EVE-treatment with a lower starting dose, trying subsequently to increase the dose to the recommended dose of 10mg to allow the patient’s organism to adapt to the therapeutic. As the study was not powered to detect possible differences in PFS by starting dose, the result of showing no detrimental effect of a lower start dose may be the result of limited power. Clinical trial information: EUPAS9462.