Research
A Cost/Benefit Analysis of Clinical Trial Designs for COVID-19 Vaccine Candidates
Berry, Donald, Scott Berry, Peter Hale, Leah Isakov, Andrew W. Lo, Kien Wei Siah, Chi Heem Wong (2020), A Cost/Benefit Analysis of Clinical Trial Designs for COVID-19 Vaccine Candidates, PLoS ONE 15(12): e0244418. https://doi.org/10.1371/journal.pone.0244418 .
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We compare and contrast the expected duration and number of infections and deaths averted among several designs for clinical trials of COVID-19 vaccine candidates, including traditional and adaptive randomized clinical trials and human challenge trials. Using epidemiological models calibrated to the current pandemic, we simulate the time course of each clinical trial design for 756 unique combinations of parameters, allowing us to determine which trial design is most effective for a given scenario. A human challenge trial provides maximal net benefits—averting an additional 1.1M infections and 8,000 deaths in the U.S. compared to the next best clinical trial design—if its set-up time is short or the pandemic spreads slowly. In most of the other cases, an adaptive trial provides greater net benefits.
Chaudhuri, Shomesh E., and Andrew W. Lo (2020),Financially adaptive clinical trials via option pricing analysis, Journal of Econometrics , 1-11.
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The regulatory approval process for new therapies involves costly clinical trials that can span multiple years. When valuing a candidate therapy from a financial perspective, industry sponsors may terminate a program early if clinical evidence suggests market prospects are not as favorable as originally forecasted. Intuition suggests that clinical trials that can be modified as new data are observed, i.e., adaptive trials, are more valuable than trials without this flexibility. To quantify this value, we propose modeling the accrual of information in a clinical trial as a sequence of real options, allowing us to systematically design early-stopping decision boundaries that maximize the economic value to the sponsor. In an empirical analysis of selected disease areas, we find that when a therapy is ineffective, our adaptive financing method can decrease the expected cost incurred by the sponsor in terms of total expenditures, number of patients, and trial length by up to 46%. Moreover, by amortizing the large fixed costs associated with a clinical trial over time, financing these projects becomes less risky, resulting in lower costs of capital and larger valuations when the therapy is effective.
© 2020 Elsevier B.V. All rights reserved.
de Castro, Leo, Andrew W. Lo, Taylor Reynolds, Fransisca Susan, Vinod Vaikuntanathan, Daniel Weitzner, and Nicolas Zhang (2020), SCRAM: A Platform for Securely Measuring Cyber Risk, Harvard Data Science Review, https://doi.org/10.1162/99608f92.b4bb506a.
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We develop a new cryptographic platform called SCRAM (Secure Cyber Risk Aggregation and Measurement) that allows multiple entities to compute aggregate cyber-risk measures without requiring any entity to disclose its own sensitive data on cyberattacks, penetrations, and losses. Using the SCRAM platform, we present results from two computations in a pilot study with six large private-sector companies: (1) benchmarks of the adoption rates of 171 critical security measures and (2) links between monetary losses from 49 security incidents and the specific sub-control failures implicated in each incident. These results provide insight into problematic cyber-risk-control areas that need additional scrutiny and/or investment, but in a completely anonymized and privacy-preserving way.
Lo, Andrew W., Alexander Remorov, and Zied Ben Chaouch (2020), Measuring Risk Preferences and Asset-Allocation Decisions: A Global Survey Analysis, Journal of Investment Management 18 (3), 5-50.
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We use a global survey of over 22,400 individual investors, 4,892 financial advisors, and 2,060 institutional investors between 2015 and 2017 to elicit their asset allocation behavior and risk preferences. We find substantially different behaviors among these three groups of market participants. Most institutional investors exhibit highly contrarian reactions to past returns in their equity allocations. Financial advisors are also mostly contrarian; a few of them demonstrate passive behavior. However, individual investors tend to extrapolate past performance. We use a clustering algorithm to partition individuals into five distinct types: passive investors, risk avoiders, extrapolators, contrarians, and optimistic investors. Across demographic categories, older investors tend to be more passive and risk averse.
Macroeconomic Models for Monetary Policy: A Critical Review from a Finance Perspective
Dou, Winston W., Andrew W. Lo, Ameya Muley, and Harald Uhlig (2020), Macroeconomic Models for Monetary Policy: A Critical Review from a Finance Perspective, Annual Review of Financial Economics 12, 95-140.
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We provide a critical review of macroeconomic models used for monetary policy at central banks from a finance perspective. We review the history of monetary policy modeling, survey the core monetary models used by major central banks, and construct an illustrative model for those readers who are unfamiliar with the literature. Within this framework, we highlight several important limitations of current models and methods, including the fact that local-linearization approximations omit important nonlinear dynamics, yielding biased impulse-response analysis and parameter estimates. We also propose new features for the next generation of macrofinancial policy models, including: a substantial role for a financial sector, the government balance sheet and unconventional monetary policies; heterogeneity, reallocation, and redistribution effects; the macroeconomic impact of large nonlinear risk-premium dynamics; time-varying uncertainty; financial sector and systemic risks; imperfect product market and markups; and further advances in solution, estimation, and evaluation methods for dynamic quantitative structural models.
Lo, Andrew W., and Kien Wei Siah (2021), Financing Correlated Drug Development Projects, Journal of Structured Finance, https://doi.org/10.3905/jsf.2020.1.114 .
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Current business models have struggled to support early-stage drug development. In this paper, we study an alternative financing model, the megafund structure, to fund drug discovery. We extend the framework proposed in previous studies to account for correlation between phase transitions in drug development projects, thus making the model a more realistic representation of biopharma research and development. In addition, we update the parameters used in our simulation with more recent estimates of the probability of success (PoS). We find that the performance of the megafund becomes less attractive when correlation between projects is introduced. However, the risk of default and the expected returns of the vanilla megafund remain promising even under moderate levels of correlation. In addition, we find that a leveraged megafund outperforms an equity-only structure over a wide range of assumptions about correlation and PoS.
Chaudhuri, Shomesh, Terence C. Burnham and Andrew W. Lo (2020), An Empirical Evaluation of Tax-Loss-Harvesting Alpha, Financial Analysts Journal 76 (3) 99-108.
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Advances in financial technology have made tax-loss harvesting more feasible for retail investors than such strategies were in the past. We evaluated the magnitude of this “tax alpha” with the use of historical data from the CRSP monthly database for the 500 securities with the largest market capitalizations from 1926 to 2018. Given long-term and short-term capital gains tax rates of 15% and 35%, respectively, we found that a tax-loss-harvesting strategy yielded a before-transaction-cost tax alpha of 1.08% per year for our sample period. When the strategy was constrained by the “wash sale rule,” the tax alpha decreased from 1.08% per year to 0.82% per year.
The Challenging Economics of Vaccine Development in the Age of COVID-19, and What Can Be Done About It
Vu, Jonathan, Ben Kaplan, Shomesh E. Chaudhuri, Monique Mansoura, and Andrew W. Lo (2020), The Challenging Economics of Vaccine Development in the Age of COVID-19, and What Can Be Done About It, DIA Global Forum 12 (5).
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The recent destructive outbreak of the novel coronavirus, SARS-CoV-2, that emerged from Wuhan, China, and rapidly spread to Europe and North America, demonstrates beyond doubt that emerging infectious diseases (EIDs) are a clear and present danger to the world and its economy. Uncontrolled outbreaks of EIDs can devastate populations around the globe, both in terms of lives lost and economic value destroyed. Emerging and re-emerging strains of infectious disease have become more diverse over time, and outbreaks have become more frequent. In 2006, Larry Brilliant stated that 90 percent of the epidemiologists in his confidence agreed that there would be a large pandemic—in which 1 billion people would sicken, 165 million would die, and the global economy would lose $1-3 trillion—within two generations. In 2020, this remarkable statement is playing out with each passing day.
Venture Philanthropy: A Case Study of the Cystic Fibrosis Foundation
Kim, Esther, and Andrew W. Lo (2019), Venture Philanthropy: A Case Study of the Cystic Fibrosis Foundation, April 23.
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Advances in biomedical research have created significant opportunities to bring to market a new generation of therapeutics. However, early-stage assets often face a dearth of funding, as they have a high risk of failure and significant development costs. Historically, this has been particularly true for assets intended to treat rare diseases, where market sizes are often too small to attract much attention and funding. Venture philanthropy (VP) — which, for the purpose of this paper, is defined as a model in which nonprofit, mission-driven organizations fund initiatives to advance their objectives and potentially achieve returns that can be reinvested toward their mission — offers an alternative to traditional funding sources like venture capital or the public markets. Here we highlight the Cystic Fibrosis (CF) Foundation, widely considered to be the leading VP organization in biotech, which facilitated the development of Kalydeco, the first disease-modifying therapy approved to treat cystic fibrosis. We evaluate the CF Foundation’s example, including its agreement structures and strategy, explore the challenges that other nonprofits may have in adopting this strategy, and draw lessons from the CF Foundation for other applications of VP financing.
Machine-Learning and Stochastic Tumor Growth Models for Predicting Outcomes in Patients With Advanced Non–Small-Cell Lung Cancer
Siah, Kien Wei, Sean Khozin, Chi Heem Wong, and Andrew W. Lo (2019), Machine-Learning and Stochastic Tumor Growth Models for Predicting Outcomes in Patients With Advanced Non–Small-Cell Lung Cancer, JCO Clinical Cancer Informatics 3, 1–11.
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The prediction of clinical outcomes for patients with cancer is central to precision medicine and the design of clinical trials. We developed and validated machine-learning models for three important clinical end points in patients with advanced non–small-cell lung cancer (NSCLC)—objective response (OR), progression free survival (PFS), and overall survival (OS)—using routinely collected patient and disease variables. We aggregated patient-level data from 17 randomized clinical trials recently submitted to the US Food and Drug Administration evaluating molecularly targeted therapy and immunotherapy in patients with advanced NSCLC. To our knowledge, this is one of the largest studies of NSCLC to consider biomarker and inhibitor therapy as candidate predictive variables. We developed a stochastic tumor growth model to predict tumor response and explored the performance of a range of machine-learning algorithms and survival models. Models were evaluated on out-of-sample data using the standard area under the receiver operating characteristic curve and concordance index (C-index) performance metrics. Our models achieved promising out-of-sample predictive performances of 0.79 area under the receiver operating characteristic curve (95% CI, 0.77 to 0.81), 0.67 C-index (95% CI, 0.66 to 0.69), and 0.73 C-index (95% CI, 0.72 to 0.74) for OR, PFS, and OS, respectively. The calibration plots for PFS and OS suggested good agreement between actual and predicted survival probabilities. In addition, the Kaplan-Meier survival curves showed that the difference in survival between the low- and high-risk groups was significant (log-rank test P, .001) for both PFS and OS. Biomarker status was the strongest predictor of OR, PFS, and OS in patients with advanced NSCLC treated with immune checkpoint inhibitors and targeted therapies. However, single biomarkers have limited predictive value, especially for programmed death-ligand 1 immunotherapy. To advance beyond the results achieved in this study, more comprehensive data on composite multiomic signatures is required.