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LUM-201, also known as ibutamoren, is an investigational, once-daily, orally administered small molecule that promotes the secretion of Growth Hormone (GH) from the pituitary gland.

LUM-201 has been observed to increase the amplitude of endogenous pulsatile GH secretion, which mimics the natural pattern of GH secretion via potent agonism of the growth hormone secretagogue receptor. Click on the video below to learn more about LUM-201’s Mechanism of Action in Pediatric Growth Hormone Deficiency (PGHD).

LUM-201 has been studied in more than 1200 patients (more than 150 children) and was generally well-tolerated.*

Important Information – *At the doses tested previously in the Merck Trials, LUM-201 was generally well-tolerated in children with the most commonly reported adverse events being digestive systems events, including appetite increase. Mild elevations in liver enzymes without accompanying changes in bilirubin were also reported.




Treatment of growth hormone deficient children is currently limited to daily or weekly injections of growth hormone. Missed injections reduce therapeutic effectiveness, resulting in suboptimal growth.1,2

Growth hormone (GH) deficiency is the consequence of inadequate secretion of growth hormone from the pituitary gland. This results in low GH in the body, insufficient production of downstream signaling molecules required for growth, and the subsequent lack of growth. In children, this rare disorder is called pediatric growth hormone deficiency (PGHD).

Secretion of GH is under strict hormonal feedback control. Growth hormone-releasing hormone (GHRH) and ghrelin are stimulators of GH production, while somatostatin activity inhibits GH production.

GH is an important hormone regulating growth in childhood and adolescence.


PGHD can be congenital (children are born with the condition), acquired (brain tumor, head injuries or other causes), iatrogenic (induced by treatment for cancer), or idiopathic (of unknown cause). Consequences of PGHD can range from severe to moderate.



Lumos Pharma is developing LUM-201, a once-daily tablet that, if successful, will provide an alternative to daily or weekly injections of growth hormone.


In children, PGHD results in and manifests as slower-than-normal growth.  Children are usually diagnosed by approximately seven years of age due to short stature and stunted growth velocity, although some children are not diagnosed until delay in pubertal growth spurt. About 1 in 3500 children are diagnosed with PGHD.3

PGHD is generally diagnosed by clinical observations and multiple tests, including radiographic assessment of bone age and tests of other hormones.

GH release stimulation tests are often needed to confirm PGHD diagnosis.


Current treatment options are limited to injectable formulations (daily or weekly) of recombinant human growth hormone (rhGH). Treatment should be started as soon as PGHD diagnosis is confirmed. Long-term (seven years or longer) treatment is not uncommon to achieve “catch-up” growth and reach full height potential. Unfortunately, any routine injection can be painful, potentially leading to missed doses and sub-optimal growth.1,2

Treatment response is assessed by measurement of height and growth velocity. Treatment is usually continued until final height, completion of skeletal bone maturation (epiphyseal closure), or both have been recorded.

The main therapeutic goal of growth hormone treatment in children with PGHD is to enable these children to achieve normal height, with accompanying improvement of the psychosocial problems related to short stature.



A Predictive Enrichment Markers (PEMs) strategy uses clinical markers to identify patients who are likely to respond to a given treatment of a disease or condition. A PEMs strategy is typically applied when a disease has a variety of causes, resulting in varied responses to available treatments.

Lumos uses two common laboratory tests (baseline IGF-1 and GH response to a single dose of LUM-201) to predict if a child is more likely to respond to LUM-201 investigational therapy (PEM positive) or less likely (PEM negative).

Pediatric Growth Hormone Deficiency (PGHD) has a number of different causes; not all patients will benefit from treatment with LUM-201. Our Phase 2 clinical trial, OraGrowtH210, uses PEMs for hypothalamic/pituitary function assessment.

Drawing from LUM-201 data that had previously shown to increase the pulsatile release of growth hormone in healthy adults and adults with Growth Hormone Deficiency (GHD), for up to 24 months, the above data image shows the effect of LUM-201 on increasing the pulsatile release of growth hormone (GH) in children with GHD (blue line on graph) compared to their baseline (grey line on graph) in a small study set. The study illustrates that small increases in GH area under the curve (AUC) from baseline are sufficient to stimulate an increase in growth. Likewise, it informs the impact of our Predictive Enrichment Marker (PEM) strategy to select for potentially responsive patients (PEM positive), as the PEM negative patient did not respond to treatment. These data have prompted our ongoing OraGrowtH212 Trial to explore increases in growth hormone pulsatility induced by LUM-201 at higher doses and in a larger cohort.


Now enrolling patients in a Phase 2 trial of orally administered LUM-201 for Pediatric Growth Hormone Deficiency

Click here to visit for more information.

Lumos Pharma is developing LUM-201 as an investigative, orally-administered product to treat a subset of children with pediatric growth hormone deficiency (PGHD). Recombinant human GH is approved for use in many other rare indications beyond PGHD including Turner syndrome, Children Born Small for Gestational Age, Prader-Willi Syndrome, Idiopathic Short Stature (ISS), and several others. Lumos Pharma plans to develop LUM-201 for treatment of several of these additional indications.

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Development of a Predictive Enrichment Marker for Oral GH Secretagogue LUM-201 in Children with Growth Hormone Deficiency

  • George M Bright, MD
  • Minh-Ha T Do, PhD
  • John C McKew, PhD
  • Werner F Blum, MD
  • Michael O Thorner, MB, BS, DSc

Journal of the Endocrine Society, Volume 5, Issue 6, June 2021, bvab030


Corroboration of Height Velocity Prediction Markers for rhGH with an Oral GH Secretagogue Treatment in Children with GHD

  • Werner F Blum, MD
  • George M Bright, MD
  • Minh-Ha T Do, PhD
  • John C McKew, PhD
  • Haiying Chen, MD, PhD
  • Michael O Thorner, MB, BS, DSc

Journal of the Endocrine Society, Volume 5, Issue 6, June 2021, bvab029


Design and biological activities of L-163,191 (MK-0677): A potent, orally active growth hormone secretagogue – A. Patchett, R. P. Nargund, J. R. Tata, M.-H. Chen, K. J. Barakat, D. B. R. Johnston, K. Cheng, W. W.-S. Chant, B. Butler, G. Hickey, T. Jacks, K. Schleim, S.-S. Pong, L.-Y. P. Chaung, H. Y. Chen, E. Frazier, K. H. Leung, S.-H. L. Chiu, and Roy G. Smith – PNAS

Optimizing Patient Management and Adherence for children receiving Growth Hormone – Carlo L. Acerini, Katarzyna Wac, Peter Bang, and Dagmar Lehwalder – Frontiers in Endocrinology

Short Stature: Comparison of WHO and National Growth Standards/References for Height – Henrik Thybo Christesen, Birgitte Tønnes Pedersen, Effie Pournara, Isabelle Oliver Petit, Pétur Benedikt Júlíusson – PLOSone

The challenge of growth hormone deficiency diagnosis and treatment during the transition from puberty into adulthood – Elena Inzaghi and Stefano Cianfarani – Frontiers In Endocrinology

Non-Compliance with Growth Hormone Treatment in Children Is Common and Impairs Linear Growth – Wayne S. Cutfield, Jose ́ G. B. Derraik, Alistair J. Gunn, Kyle Reid, Theresa Delany, Elizabeth Robinson, Paul L. Hofman – PLOS One

Growth Hormone Research Society Perspective on Biomarkers of GH Action in Children and Adults – Gudmundur Johannsson, Martin Bidlingmaier, Beverly M K Biller, Margaret Boguszewski, Felipe F Casanueva, Philippe Chanson, Peter E Clayton, Catherine S Choong, David Clemmons, Mehul Dattani, Jan Frystyk, Ken Ho, Andrew R Hoffman, Reiko Horikawa, Anders Juul, John J Kopchick, Xiaoping Luo, Sebastian Neggers, Irene Netchine, Daniel S Olsson, Sally Radovick, Ron Rosenfeld, Richard J Ross, Katharina Schilbach, Paulo Solberg, Christian Strasburger, Peter Trainer, Kevin C J Yuen, Kerstin Wickstrom, Jens O L Jorgensen, and the Growth Hormone Research Society


1. Rosenfeld, R. et al, Compliance and Persistence in Pediatric and Adult Patients Receiving Growth Hormone Therapy, Endocrine Practice, 2008, 14(2):143-154

2. Cutfield, W.S. et al, Non-Compliance with Growth Hormone Treatment in Children Is Common and Impairs Linear Growth, PLOS ONE, 2011, 6(1): e16223

3. Lindsay Journal of Pediatrics, 1994, 125(1):29-35