Tuesday, September 24, 2019

Lucy Xiaolu Wang on the Medicines Patent Pool

Patent pools are agreements by multiple patent owners to license related patents for a fixed price. The net welfare effect of patent pools is theoretically ambiguous: they can reduce numerous transaction costs, but they also can impose anti-competitive costs (due to collusive price-fixing) and costs to future innovation (due to terms requiring pool members to license future technologies back to the pool). In prior posts, I've described work by Ryan Lampe and Petra Moser suggesting that the first U.S. patent pool—on sewing machine technologies—deterred innovation, and work by Rob Merges and Mike Mattioli suggesting that the savings from two high tech pools are enormous, and that those concerned with pools thus have a high burden to show that the costs outweigh these benefits. More recently, Mattioli has reviewed the complex empirical literature on patent pools.

Economics Ph.D. student Lucy Xiaolu Wang has a very interesting new paper to add to this literature, which I believe is the first empirical study of a biomedical patent pool: Global Drug Diffusion and Innovation with a Patent Pool: The Case of HIV Drug Cocktails. Wang examines the Medicines Patent Pool (MPP), a UN-backed nonprofit that bundles patents for HIV drugs and other medicines and licenses these patents for generic sales in developing countries, with rates that are typically no more than 5% of revenues. For many diseases, including HIV/AIDS, the standard treatment requires daily consumption of multiple compounds owned by different firms with numerous patents. Such situations can benefit from a patent pool for the diffusion of drugs and the creation of single-pill once-daily drug cocktails. She uses a difference-in-differences method to study the effect of the MPP on both static and dynamic welfare and finds enormous social benefits.

On static welfare, she concludes that the MPP increases generic drug purchases in developing countries. She uses "the arguably exogenous variation in the timing of when a drug is included in the pool"—which "is not determined by demand side factors such as HIV prevalence and death rates"—to conclude that adding a drug to the MPP for a given country "increases generic drug share by about seven percentage points in that country." She reports that the results are stronger in countries where drugs are patented (with patent thickets) and are robust to alternative specifications or definitions of counterfactual groups.

On dynamic welfare, Wang concludes that the MPP increases follow-on innovation. "Once a compound enters the pool, new clinical trials increase for drugs that include the compound and more firms participate in these trials," resulting in more new drug product approvals, particularly generic versions of single-pill drug cocktails. And this increase in R&D comes from both pool insiders and outsiders. She finds that outsiders primarily increase innovation for new and better uses of existing compounds, and insiders reallocate resources for pre-market trials and new compound development.

Under these estimations, the net social benefit is substantial. Wang uses a simple structural model and estimates that the MPP for licensing HIV drug patents increased consumer surplus by $700–1400 million and producer surplus by up to $181 million over the first seven years of its establishment, greatly exceeding the pool's $33 million total operating cost over the same period. Of course, estimating counterfactuals from natural experiments is always fraught with challenges. But as an initial effort to understand the net benefits and costs of the MPP, this seems like an important contribution that is worth the attention of legal scholars working in the patent pool area.

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