About This Trial

PF-06252616 in Duchenne Muscular Dystrophy

This is a phase 2 clinical trial designed to evaluate the safety and tolerability, efficacy, pharmacokinetics (the drug levels in the body) and pharmacodynamics (effects the drug has on the body) of an investigational drug, PF-06252616, in boys diagnosed with Duchenne muscular dystrophy (DMD) who are 6 to 15 years old and able to walk.

This investigational drug is in the clinical trial phase and not approved for use by any regulatory agencies (i.e. USA Food and Drug Administration and other regulatory agencies). Therefore, the drug is considered investigational.

Read More Information on clinicaltrials.gov


PF-06252616 is an investigational engineered protein, a monoclonal antibody that was designed to bind to and inhibit myostatin.

The investigational drug, PF-06252616, was made to target myostatin, a naturally occurring protein in muscle, that is normally produced by the body to keep the muscles from growing too large.


This phase 2 trial in DMD is a randomized placebo-controlled trial with 105 male participants, age 6 to 15 years-old. The investigational drug is given to participants through a two-hour, intravenous (IV) infusion every 4 weeks. The infusion takes place at a hospital or clinic where the trial is being conducted. Participants must be ambulatory (able to walk) and able to perform the four-stair climb with or without the use of handrails.

The trial will have two periods and each period will run for 48 weeks. At the beginning of the trial, boys will be randomly assigned to one of three groups. The first group will receive the investigational drug in period 1 and remain on a stable dose of drug in period 2. The second group will also receive the investigational drug in period 1 but in period 2, they will switch to a placebo (looks like the investigational drug, but with no active components). The third group will receive placebo in period 1 and then the investigational drug in period 2. The trial will be blinded, so the company developing the drug (Pfizer), the doctors (investigators) and their staff running the trial, and the trial participants and their families won’t know which group participants have been assigned to during the trial. This approach will allow the investigators to see both the effect of starting and stopping the drug as well as the effects of constant exposure over a long period of time of the same dose. It’s likely that the drug will take a while to actually “wash out” out of the body, so the participants in the group that is transitioned to placebo may still have some of the investigational drug in their system during the placebo period of the trial.

The primary endpoint for the investigational drug in this trial is a change from baseline in the four-stair climb after 48 weeks of trial participation as compared to the placebo.   Secondary endpoints include evaluating the change from baseline of participants on other functional tests including the forced vital capacity, Northstar Ambulatory Assessment, the six-minute walk test, muscle strength, range of motion, and Performance of Upper Limb (PUL).   Additional secondary endpoints include an evaluation in the change from baseline in thigh muscle volume as measured by magnetic resonance imaging (MRI).

The investigational drug will be given as a two-hour IV infusion every 4 weeks. For each participant, the dose level may increase every 4 months depending on how well the drug is tolerated. If any safety issues are observed at a given dose level, the dose may either remain the same or be decreased or dosing may be terminated.

The participants will have monthly clinic visits to the investigational sites, some visits will require attendance on two consecutive days, the trial involves a number of MRI scans, and frequent testing of strength, walking and stair climbing ability.

Participants who complete this trial may also be invited to participate in an open-label trial (an extension of this trial where the participants and their families will know they are receiving the investigational study drug).


Sites for the trial will be in the US, Canada, Japan, the United Kingdom, Italy, Poland, Australia and Bulgaria. The majority of the trial sites will be located in the United States. Open sites are posted on ClinicalTrials.gov. All sites will not start at the same time, so you may want to check back to see if additional sites are added in your area.