scholarly journals Mechanism Design With Aftermarkets: Cutoff Mechanisms

Econometrica ◽  
2020 ◽  
Vol 88 (6) ◽  
pp. 2629-2661 ◽  
Author(s):  
Piotr Dworczak

I study a mechanism design problem in which a designer allocates a single good to one of several agents, and the mechanism is followed by an aftermarket—a post‐mechanism game played between the agent who acquired the good and third‐party market participants. The designer has preferences over final outcomes, but she cannot design the aftermarket. However, she can influence its information structure by publicly disclosing information elicited from the agents by the mechanism. I introduce a class of allocation and disclosure rules, called cutoff rules, that disclose information about the buyer's type only by revealing information about the realization of a random threshold (cutoff) that she had to outbid to win the object. When there is a single agent in the mechanism, I show that the optimal cutoff mechanism offers full privacy to the agent. In contrast, when there are multiple agents, the optimal cutoff mechanism may disclose information about the winner's type; I provide sufficient conditions for optimality of simple designs. I also characterize aftermarkets for which restricting attention to cutoff mechanisms is without loss of generality in a subclass of all feasible mechanisms satisfying additional conditions.

BMJ Open ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. e041463
Author(s):  
Anita Mansouri ◽  
Naomi McGregor ◽  
Rachel Dunn ◽  
Sam Dobbie ◽  
Jane Holmes ◽  
...  

IntroductionPatients relapsing within 12 months of platinum-based chemotherapy usually have a poorer response to subsequent treatments. To date, extensive research into the mechanism of resistance to platinum agents in the treatment of ovarian cancer has not resulted in improved responses or longer survival. Further experimental work and clinical trials with novel agents are therefore justified to address this unmet need.Patients with ovarian, fallopian tube or primary peritoneal cancer that has relapsed within 12 months of platinum-based chemotherapy will be randomised with stratification for BReast CAncer gene (BRCA) status, prior poly (ADP-ribose) polymerase (PARP) exposure and prior antiangiogenic therapy into weekly paclitaxel (chemotherapy), olaparib or the combination of cediranib and olaparib. They will be followed until disease progression or unacceptable toxicity develops. Our trial design permits two investigations. We will compare the efficacy and tolerability of single-agent olaparib with weekly paclitaxel. We will also compare the efficacy and tolerability of olaparib with the combination of olaparib and cediranib. The required sample size of 138 participants (46 per arm) was calculated using a 20% one-sided type I error, 80% power and 15% dropout rate. Recruitment will last 34 months with a follow-up of 18 months.Methods and analysisEthics and disseminationThis study will be conducted under a UK Medicines and Healthcare Products Regulatory Agency Clinical Trials Authorisation. Approval to conduct the study was obtained from the responsible authority before beginning the study. The sponsor will retain ownership of all data arising from the trial. We aim to publish this research in a specialist peer-reviewed scientific journal on study completion. EudraCT number: 2016-000559-28, ethics reference number: 16/LO/2150.Trial registration numberISRCTN: ISRCTN14784018, clinicaltrials.gov: NCT03117933; Pre-results.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 8039-8039
Author(s):  
Ehsan Malek ◽  
Sunjin Hwang ◽  
Paolo Fabrizio Caimi ◽  
Leland L. Metheny ◽  
Benjamin Kent Tomlinson ◽  
...  

8039 Background: Immunosuppression and osteoclast activation are two hallmarks of the bone marrow environment in Multiple Myeloma (MM). Corticosteroids have been used historically as part of anti-myeloma regimens due to their anti-plasma cell activity, however they potentially could suppress immune system and activate osteoclast further; therefore there is an unmet need for corticosteroid-free approaches in the era of emerging anti-cancer immunotherapy modalities. There is an abundance of Transforming Growth Factor-beta (TGF-β), a crucial cytokine in suppression of immune system as well as catabolic bone remodeling, in the MM microenvironment. Vactosertib (Vacto) is a small molecule TGF-β type I receptor inhibitor that has shown single agent activity against myeloma in the syngeneic 5T33MM murine mouse model. Here, we report the phase Ib trial of Vacto in combination with pomalidomide (Pom) without any corticosteroids (NCT03143985). Methods: pts with relapsed MM with at least two lines of therapies enrolled on a 3 + 3 dose escalation design and received Vacto, 60 mg/d, 120 mg/d, 100 mg BID and 200 mg BID in combination with standard dose of Pom (4mg) without corticosteroids. The primary objectives of the study was to assess safety and recommended phase 2 dose. Vacto tablets, taken once or twice daily for 5 days followed by 2 days without treatment, is administered in 28-day cycles, until progression of disease or intolerable toxicity. Results: 15 pts were enrolled on the study (Table). The most common non-hematologic adverse event (AE) was grade II fatigue and pain in one pt, one episode of grade III renal failure that took less than 7 days to get back to baseline on another patient, sinus bradycardia that reversed to sinus rythem and an Afib that was rate controlled with beta blocerks. No grade IV non-hematologic AE was observed. Three pts had grade III hematologic AE, no grade IV hematologic AE. Three out of 15 pts experienced progression of disease (PFS-6: 80%). Conclusions: The phase Ib data shows safety of this agent in combination with Pom. The efficacy assessment (PFS-6: 80%) is higher than the historical control (PFS-6: 20% in randomized Phase II study by Richardson et al. Blood. 2014) with Pom only (PFS-6: 20%) or Pom with corticosteroids (PFS-6: 40%). Further advancement of this agent in clinical trial pipelines for MM is planned. Clinical trial information: NCT03143985. [Table: see text]


2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Thiruma V. Arumugam ◽  
Christopher Sobey

The canonical Notch signalling pathway has four type I transmembrane Notch receptors (Notch1-4) and five ligands (DLL1, 2 and 3, and Jagged 1-2). Each member of this highly conserved receptor family plays a unique role in cell-fate determination during embryogenesis, differentiation, tissue patterning, proliferation and cell death [2]. As the Notch ligands are also membrane bound, cells have to be in close proximity for receptor-ligand interactions to occur. Cleavage of the intracellular domain (ICD) of activated Notch receptors by γ-secretase is required for downstream signalling and Notch-induced transcriptional modulation [15, 3, 11, 22]. This is why γ-secretase inhibitors can be used to downregulate Notch signalling and explains their anti-cancer action. One such small molecule is RO4929097 [8], although development of this compound has been terminated following an unsuccessful Phase II single agent clinical trial in metastatic colorectal cancer [19].Aberrant Notch signalling is implicated in a number of human cancers [12, 20, 6, 16], with demcizumab and tarextumab identified as antibody inhibitors of ligand:receptor binding [13].


2002 ◽  
Vol 65 (2) ◽  
pp. 289-306 ◽  
Author(s):  
Nguyen Xuan Ha ◽  
Do Van Luu

Under suitable assumptions we establish the formulas for calculating generalised gradients and generalised directional derivatives in the Clarke sense of the supremum and the infimum of an infinite family of Lipschitz functions. From these results we derive the results ensuring such a supremum or infimum are an invex function when all functions of the invex. Applying these results to a class of mathematical programs, we obtain necessary and sufficient conditions for optimality.


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