Lotus is the nation's top enrolling site into opioid induced constipation studies.
We have a mature database of over 12,000 chronic pain volunteers and have successfully completed numerous OIC investigations (both early and late phase). If your OIC investigation is still in the design phase, Lotus can provide critical insights on; expected run-in failure rate based on study specific I/E criteria, techniques to improve subject diary compliance and methods to rate/ adjudicate CNS adverse events.


Lotus has the nations largest OIC Database consisting of over 12,000 study volunteers with chronic pain. The database is mature, well maintained and sortable for criteria specific to OIC studies such as; total daily morphine mEq intake, historical weekly bowel movement frequency and pain etiology. Many patients in our database are well known to us and as such we have had a chance to vet them for accuracy and reliability.

Enrollment History

PhaseSponsorEnrollment Period (months)Enrolled by LotusTotal Study NCommentsCTG link
2 Alkermes 7 14 60 Top Enroller NCT01100151
3 Progenics/Salix 5 39 700 Top Enroller NCT01186770
1 Adolor 3 22 22 Single Site, Multi-day Confinement Not Available (Phase 1)
2a Adolor 6 77 120 Top Enroller NCT01207427
1 Adolor 2 24 24 Single Site Not Available (Phase 1)
1/2 Theravance 2 29 70 Top Enroller NCT01040637
1 Adolor 1 7 24 *Rescue Site Not Available (Phase 1)
1 Adolor 1.5 20 30 *Rescue Site Not Available (Phase 1)

*Contracted as a rescue site. Lotus wrapped up enrollment in less than 1.5 months with an enrollment rate 5 times faster than that of the original research center.

OIC Confirmation Period

Appropriate design and execution of the OIC confirmation period is a critical element of a successful OIC study. Lotus has experience with several run-in schemas including those that involve a single blind placebo. We can provide expertise and advice as to which run-in schema makes sense for your particular program. Once chosen, the run-in phase will have a significant impact on enrollment numbers and effect size. In general, mandating <3 SBM's per week is appropriate but the calculation of this figure has many important nuances. Capturing precise diary data during the OIC confirmation period requires a compliant patient who is willing to collaborate with the research coordinator. The appropriately educated study subject should be able to clearly define an SBM, understand how and when to use rescue laxatives and accurately report their baseline narcotic usage.

CNS & Gastrointestinal Adverse Event Adjudication

Properly evaluating central and gastrointestinal withdrawal symptoms requires not only training but also a significant amount of experience. At Lotus we have enrolled hundreds of patients into OIC trials and therefore our physicians, allied health professionals and study coordinators have the requisite knowledge to accurately evaluate and adjudicate OIC related adverse events. Gastrointestinal withdrawal symptoms can range from mild and tolerable to severe and disabling. In many early phase protocols, severe GI symptoms are an MTD criteria, making appropriate assessment of GI AEs even more critical. CNS withdrawal is a safety concern for any opioid antagonist. Beyond understanding how to conduct COWs and SOWs questionnaires, the site must also ensure that the patient has adequate opioid reserves so that their baseline opioid intake is not disrupted. These disruptions can lead to inadvertent withdrawal not related to the study medication which can confound study results.