Beyond Achondroplasia

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Meclozine for achondroplasia heading to clinical trial


In February 2015, Matsushita et al., published “Meclozine Promotes Longitudinal Skeletal Growth in Transgenic Mice with Achondroplasia Carrying a Gain-of-Function Mutation in the FGFR3 Gene” (here in a short report in Beyond Achondroplasia) and shortly after in 2015, the same team also published “Meclozine as potential effects on short stature and foramen magnum stenosis in transgenic mice with achondroplasia“, that is discussed in the post “Talking with Prof. Matsushita” in Beyond Achondroplasia

The Japanese team from Nagoya University that conducted these studies on meclozine for achondroplasia, early observed that the mice with achondroplasia treated for 3 weeks with 0,4mg/kg meclizine/meclozine once a day, had an estimated annual growth rate of 4 cm growth/year. (1)

More, the team observed an increase in the global length (vertebrae in the spine) as well as the increase of the bone lengths of the radius, ulna (arm bones), femur, tibia (leg bones) and reduced bony bridges around foramen magnum, what is related to cervicomedullary stenosis.(1)

And they also observed restored proportionality in these mice with achondroplasia after the 3 weeks of treatment with meclozine. Is relevant to take into account that the lifespan of a lab mouse is around 40 weeks. (1)

So, 3 years after the first publication, the team anticipates the clinical trial start date to be the 30th July 2018, and it will be conducted in Japan, at Nagoya University Hospital.


Following the information available in the official site UMIN-CTR Clinical Trial: (3)

Official scientific title of the study Safety and pharmacokinetics of meclizine hydrochloride for achondroplasia children
Title of the study (Brief title) Safety and pharmacokinetics of meclizine


Narrative objectives1 Examination of safety as well as 24-hour pharmacokinetics and accumulation at 1 week after a single dose of meclizine.
Basic objectives2 Safety

Pharmacokinetics (PK) is the study of the time course of drug absorption, distribution, metabolism,
and excretion. Clinical pharmacokinetics is the application of pharmacokinetic principles to the safe and effective therapeutic management of drugs in an individual patient. Primary goals of clinical pharmacokinetics include
enhancing efficacy and decreasing toxicity of a patient’s drug therapy. (3)

Primary outcomes
  • 24-hour pharmacokinetics of meclizine
  • drug accumulation
  • adverse events and side effects
Key secondary outcomes Simulation of pharmacokinetics in the repeated administration of meclizine for 14 days

The primary outcomes are the immediate goals of this study, that is the Pharmacokinetics of meclizine in the children bodies.

Age-lower limit
5 years-old <=
Age-upper limit
11 years-old >
Gender Male and Female
Key inclusion criteria achondroplasia children
Key exclusion criteria body weight of less than 11 kg
Target sample size 12

Meclozine for achondroplasia – Phase 1 clinical trial 

The phase 1 will include 6 children that will take a single dose of Meclozine/meclizine (25mg/day). The team predicts to run a double dose study with the administration of 50mg/day (25mg twice per day) in other 6 children at the end of the year.

This is a critical study to evaluate the safety of Meclizine in young children.

Meclozine is already available in the market under several brand names, for the treatment of motion sickness, vertigo, nausea, and vomiting in adults and in children over 12 years old (5). But once there is no information of the use of meclozine in children under 12 years-old but is available adult PK data, now is required to know the PK for children. This is the reason why in this study, the phase 1 will include directly children and not healthy adults as like in another clinical trial, because the safety in adults is already known.


Example of a commercial brand of meclizine available in the market. Image credits: Phoenix Medical Services


Repurposing drug for rare diseases

This is related to discovering new uses for approved drugs to provide the quickest possible transition from bench to bedside (6), or in other words, reducing the time from the early laboratory investigation until having a drug approved and available in the market for a specific disease.

Why repurposing drugs?

There is a poor success rate (16%) for drugs entering clinical trials, with a development timeline of 12 to 15 years and a jaw-dropping price tag approaching $1 billion, it makes economic sense for drug developers to explore better therapeutic fits for failed drugs. (7)

Meclozine for Achondroplasia – Phase 2

The team will conduct a 14 days administration safety study after this two PK studies (25mg/day and 50 mg/day).


  1. Matsushita M et al., Meclozine Promotes Longitudinal Skeletal Growth in Transgenic Mice with Achondroplasia Carrying a Gain-of-Function Mutation in the FGFR3 Gene, Endocrinology, Volume 156, Issue 2, 1 February 2015, Pages 548–554
  2. Matsushita M et al., Meclozine has potential effects on short stature and foramen magnum stenosis in transgenic mice with achondroplasiaBone Abstracts (2015) 4 OC13
  3. UMIN-CTR clinical trial
  4. Introduction to Pharmacokinetics and Pharmacodynamics, ASHP
  5. Meclizine,
  6. Repurposing drugs, NCATS
  7. Repurposing drugs for rare diseases, Eureka


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