Five to ten years.  That's how long it will be before drug reimbursement in the United States becomes as stringent as in Europe, according to a range of consultants, analysts, and health policy experts with whom I've spoken.

This new reimbursement environment - and the expectations leading up to it - is expected to emphasize the value of "profound" innovation, at the expense of less dramatic, incremental innovation.

The pharmaceutical innovations most stakeholders seem to want - from payors to clinicians (see this thoughtful analysis from Avorn and Kesselheim) - are either improvements in efficacy or new mechanisms (which are often presumed, at least initially, to offer significant new options for patients).

There's also seems to be an evolving sense that such innovation is possible.  A palpable excitement surrounds the recent advances in cancer immunotherapy, for example - real conviction that revolutionary, impactful therapeutics will emerge from this area.

U.S. regulators, for their part, have clearly signaled their interest in accelerating just this sort of "important" innovation.  Patients, too, follow research advances with increasing sophistication, and will often flock to studies of especially promising new therapeutics, enabling unusually rapid recruitment, often a limiting factor in clinical studies.

Where will this leave incremental innovation?  There's no question that it will become more challenging and more expensive, since there will be far more pressure to demonstrate measurable improvement over previous products.

But it may also be premature to write off incremental innovation in biopharma.

• The relatively low technical risk (compared to targeting a novel mechanism) will remain attractive and compelling.
• The measurement technologies of digital health (as I've suggested) may help provide evidence for meaningful differentiation.
• U.S. patients and physicians may demand and continue to support the development of continuously improved products.  Many stakeholders recognize that while small improvements (e.g. in tolerability and safety) are often systematically undervalued, they can have a huge impact over time.  Examples include the evolution of HIV therapy, or (as Darshak Sanghavi has argued in Slate) advances in pediatric oncology.
• The market opportunity for incrementally improved products may turn out to be relatively undervalued.  Forecasting (as I've noted) is a dark art, and the reimbursement environment in the U.S. may evolve less rapidly than predicted, or arrive at a less restrictive end-state than most anticipate.

The hope is that as the U.S. healthcare system lurches forward, rebalanced incentives will stimulate investment in high-risk projects and enterprises, while preserving the unsexy but important incremental improvements upon which medical advancement depends.  The worry is that without just the right balance, we risk cutting off an important path to progress.