Last updated: May 22, 2026
Entereg (alvimopan): clinical trials update, market analysis, and exclusivity-driven launch projections
Executive summary: Entereg (alvimopan) is an opioid antagonist used for postoperative ileus (POI) reduction after bowel resection. The clinical-trials pipeline is not active in the same way as newer assets; market growth is constrained by safety communications, payer and prescriber adoption limits, and the drug’s restricted-use framework. Near-term commercial projections are largely driven by (1) POI incidence in eligible surgical cohorts, (2) hospital formulary positioning, and (3) ongoing uptake under restricted labeling rather than by new phase-advancing programs.
What is Entereg (alvimopan) and how is it used for postoperative ileus?
Core indication. Entereg (alvimopan) is indicated to accelerate time to upper and lower gastrointestinal recovery following bowel resection surgery and to reduce the risk of postoperative ileus. It is used in the inpatient perioperative setting, with administration limited to a defined period around surgery.
Label constraints that shape the market
- Restricted patient exposure window: labeling limits treatment duration and cumulative dosing exposure to reduce risk of serious adverse events tied to opioid withdrawal or ischemic events reported with other dosing patterns and longer exposure.
- Inpatient, hospital-administered economics: usage is driven by surgical case volume, protocol compliance, and hospital formularies.
Dosing and administration (high-level)
- First dose given prior to surgery; subsequent dosing after surgery for the limited labeled duration.
- Treatment is tied to bowel resection operations, not general opioid-associated constipation.
What clinical trials exist for Entereg (alvimopan), and what is the latest update?
Key historical evidence base
- Pivotal randomized trials evaluated alvimopan versus placebo for time to upper/lower GI recovery after bowel resection, typically measuring end points such as time to first flatus, time to toleration of oral intake, and incidence or duration of POI.
What the current “update” effectively means for Entereg
- The public, phase-advancing late-stage pipeline for Entereg is limited. Most “updates” in the market come from:
- postmarketing safety communications and label tightening,
- reassessment of real-world adoption by hospitals and surgeons,
- local guideline incorporation rather than new pivotal trials.
How trial activity translates into commercial risk
- Without a steady cadence of new clinical readouts or new indications, Entereg’s competitive posture depends mainly on:
- entrenched hospital usage patterns,
- payer coverage and prior authorization behavior,
- competing POI strategies (enhanced recovery protocols, other perioperative agents, and conservative management).
What is the FDA Orange Book status of Entereg (alvimopan), and when does it lose exclusivity?
Orange Book and exclusivity framework
Entereg is an approved, small-molecule drug. Exclusivity and patent terms determine generic entry risk. For a complete exclusivity-and-expiration map, the Orange Book listing must be reviewed entry-by-entry (drug product, NDA, and associated patents). The exclusivity and patent schedule also governs timing for potential ANDA filings (for the drug product) and for any 505(b)(2) route that relies on published data.
Featured-snippet answer
- Entereg’s generic availability and launch timing are determined by the Orange Book patent and exclusivity expirations for the specific NDA drug products, plus any Orange Book-listed patents covering formulation, method-of-use, or manufacturing.
Practical implication for projections
- If relevant Orange Book patents remain listed and enforceable, generic market penetration will be delayed and Entereg revenue will persist through the end of exclusivity and patent term.
- If Orange Book coverage has cleared, market share shifts to lower-priced generics can materially reduce revenue.
No Orange Book listing details were provided in the prompt, and a complete, accurate exclusivity-and-expiration timeline cannot be produced without those specific listings for the Entereg NDA and product(s).
How strong is the patent estate for Entereg (alvimopan) and what patents cover postoperative ileus use?
Patent estate determinants
A robust estate for Entereg would typically include:
- formulation or composition-of-matter patents,
- method-of-use patents for POI reduction after bowel resection,
- manufacturing-process patents.
How to map enforceability to launch risk
- Orange Book-listed patents create the ANDA “trigger” for Paragraph IV challenges.
- Method-of-use coverage can block generic entry if the generic does not carve out the protected dosing regimen or indication.
Featured-snippet answer
- The strength of the Entereg patent estate depends on which patents are Orange Book-listed and whether they are composition-of-matter, method-of-use, or formulation/manufacturing patents tied to the approved POI indication.
No patent-number list, assignees, or expiration dates were provided; a complete estate-strength assessment would be non-actionable without those exact Orange Book entries and associated patent documents.
What generic entry risks exist for alvimopan (Entereg), and how would a Paragraph IV challenge play out?
Generic pathway mechanics
- An ANDA would need to reference the approved NDA and seek approval for the same drug product strength and indication.
- If Orange Book patents remain in force, a generic must address them, often through a Paragraph IV certification.
Commercial impact of a successful Paragraph IV
- If patents are invalidated, unenforceable, or not infringed, the generic can launch with significant price pressure.
- If the brand prevails, generic launch is delayed by statutory stay and the litigation outcome.
Featured-snippet answer
- Entereg generic entry risk is determined by which patents are Orange Book-listed at the time of ANDA filing and whether those patents are challenged successfully.
Accurate risk quantification requires known Orange Book patents and litigation history for those specific patents; none were provided.
What FDA regulatory status governs Entereg (alvimopan) use and labeling restrictions?
Regulatory posture
- Entereg is an FDA-approved drug with labeling constraints that restrict dosing exposure. Those constraints shape utilization and can limit market expansion into broader inpatient opioid pathways.
Safety communications
- For drugs in this class and dosing profile, the FDA has historically targeted exposure limits to mitigate serious adverse events. These communications drive prescribing behavior and pharmacy stocking decisions.
How labeling changes affect market
- If labeling is tightened, hospitals may reduce use, even if patients are eligible clinically.
- If labeling is expanded, adoption can increase, but this typically requires clinical evidence and FDA review.
Specific FDA label revision dates and the exact current dosing restrictions require reference to the latest FDA label; none were provided.
Market analysis: how big is the Entereg opportunity and what drives hospital purchasing decisions?
Demand drivers
- Surgical volume: bowel resections in eligible populations (inpatient) are the key demand lever.
- POI protocol adoption: enhanced recovery after surgery (ERAS) pathways influence perioperative management, length of stay, and GI recovery targets.
- Payer coverage: reimbursement rates and prior authorization practices influence net price and stocking.
- Operating room and pharmacy workflows: Entereg is administered perioperatively; availability, order-set inclusion, and pharmacy procurement logistics matter.
Supply and competitive dynamics
- If Entereg has no direct generic competitor, pricing pressure is limited.
- Competitive alternatives are often non-identical mechanisms: other strategies for POI reduction, conservative management, and perioperative care pathways.
Commercial constraints specific to alvimopan
- Restricted labeling limits practical utilization.
- Safety monitoring requirements and institutional risk tolerance influence use.
Featured-snippet answer
- The Entereg market is primarily constrained by eligible case volume and restricted dosing adoption, not by broad outpatient demand.
Market projection scenarios for Entereg (alvimopan): base, downside, upside
Because the prompt does not include current revenue, unit sales, pricing, or known generic/patent timelines, projections must be stated as framework scenarios tied to drivers rather than numerical forecasts. A numeric forecast would require at least: current global and US net sales, market size baselines (eligible bowel resection cases), and enforceable exclusivity expiration dates.
Base case (typical “steady-state”
- Entereg maintains its share among hospitals running POI reduction protocols.
- Uptake remains stable as ERAS matures but does not replace alvimopan where formulary is already established.
- No major patent clearance or forced generic entry within the projection period.
Downside case (coverage or substitution pressure)
- Tightened payer criteria or negative safety perception reduces formulary coverage.
- Hospital protocols shift toward alternative perioperative regimens.
- A loss of exclusivity or a near-term generic entry causes sharp unit and price erosion.
Upside case (incremental protocol adoption)
- Broader inclusion in perioperative order sets due to outcome evidence in real-world settings.
- Improved safety confidence supports higher utilization within labeled exposure limits.
- No generic entry and stable net pricing.
How does Entereg compare with other postoperative ileus treatments?
Competitive comparison axes
- Mechanism: alvimopan is a peripherally acting opioid antagonist. Competitors include supportive measures and other perioperative agents.
- Target population: Entereg is tied to bowel resection and a controlled inpatient dosing window.
- Outcome endpoints: time to GI recovery and POI resolution.
Featured-snippet answer
- Entereg’s differentiator is mechanism and evidence in bowel resection POI; its limitation is restricted labeling that narrows real-world utilization.
What Entereg commercialization risks matter most to investors and licensors?
Key risks
- Regulatory and safety-driven utilization: any additional label restrictions or enforcement around dosing exposure would compress use.
- Patent-driven price erosion: Orange Book clearance and generic entry would change net price dynamics quickly.
- Clinical protocol substitution: if POI reduction increasingly relies on non-alvimopan strategies, volume could shift away even without generic competition.
- Payer formulary dynamics: hospital buy-and-bill economics and managed care reimbursement can shift quickly.
What does the litigation landscape for Entereg indicate about future exclusivity?
A litigation assessment requires:
- known patent numbers,
- case captions and jurisdictions,
- settlement terms (for generic delay and launch dates),
- court rulings and appeal status.
No Entereg litigation details were supplied, so the litigation-driven forecast cannot be built without introducing inaccuracies.
Entereg key data table (placeholders where prompt inputs are missing)
| Category |
Required data fields |
Status in prompt |
| NDA / Orange Book listings |
NDA number, drug product IDs, patent numbers, exclusivity codes, expiration dates |
Not provided |
| Patent estate |
Composition-of-matter, method-of-use, formulation/manufacturing patents, assignees, expirations |
Not provided |
| Clinical trial update |
Latest phase status, study IDs, topline results, enrollment/termination dates |
Not provided |
| Market metrics |
Current US/EU net sales, prescriptions, price per unit, eligible case volumes |
Not provided |
| Litigation |
Case dockets, Paragraph IV filings, settlements, timelines |
Not provided |
| Forecast horizon |
Years, geography, model structure |
Not provided |
Key Takeaways
- Entereg’s market is driven by inpatient bowel resection case volume and hospital adoption of POI protocols under restricted-label dosing.
- The clinical-trials picture is largely “mature” with limited late-stage pipeline signals; commercial outcomes hinge more on utilization and payer behavior than new clinical entrants.
- Exclusivity and patent status determine generic entry risk and the most material revenue inflection points.
- A numeric market projection requires Orange Book and current sales/baseline case-volume inputs; without them, only driver-based scenario structure is actionable.
FAQs
- Is alvimopan used for opioid-induced constipation outside the inpatient setting?
- How do enhanced recovery protocols affect postoperative ileus drug utilization in hospitals?
- What would a generic alvimopan ANDA need to certify to enter the market?
- Which endpoints in Entereg trials most influence hospital formulary decisions?
- How do dosing exposure limits in Entereg labeling change eligible utilization rate?
References (APA)
No sources were cited because the prompt did not include specific FDA label versions, Orange Book entries, patent numbers, or trial identifiers needed to produce a citation-backed clinical update and market/projection model.
