Industry Partner News: Pfizer Announces Decision to Discontinue Domagrozumab Clinical Studies

Today, Pfizer announced the disappointing news that it is discontinuing its clinical studies of Domagrozumab. Please read their letter and press release below for more information.

Dear Jett Foundation,

It is with profound disappointment that we announce our decision to discontinue the
clinical studies evaluating domagrozumab for the treatment of Duchenne muscular
dystrophy (DMD). The two ongoing clinical trials include; a Phase 2 safety and efficacy
study (B5161002) and an open-label extension study (B5161004). The decision comes
following completion of the primary analysis. The primary analysis was based on a
statistical test which compared the difference in the time to climb 4 standard stairs
(known as the 4 Stair Climb) after 1 year of treatment with domagrozumab as compared
to placebo treated subjects. This analysis showed no statistical difference between these
two groups at the one year period. Evaluation of the totality of evidence, including
secondary endpoints, also did not support a significant treatment effect. It is important
to note that the studies were not discontinued for safety reasons.

The discontinued Phase 2 double-blind, placebo-controlled, multicenter, clinical trial
investigated the efficacy and safety of domagrozumab, administered in monthly IV doses,
in 121 boys aged 6 to 15 with DMD, regardless of underlying mutation. It was designed as
a two-year, placebo-controlled study (with the above noted primary analysis performed
after one year); all subjects used background corticosteroid management. The primary
efficacy endpoint was mean change from baseline in 4 Stair Climb (in seconds). Secondary
endpoints included evaluation of the change from baseline of participants on other
functional tests, including forced vital capacity, Northstar Ambulatory Assessment, the
six-minute walk test, muscle strength, range of motion, and Performance of Upper Limb
(PUL). For more information, please visit www.clinicaltrials.gov (NCT02310763).

We expect that this news will deeply disappoint the many families living with DMD who
directly participated in the study, as well as all of the families living with DMD hoping for
therapies that will alter the trajectory of this devastating disease. In recognition of the
continued burden of unmet needs in DMD, Pfizer continues to advance research and
clinical development efforts focused on DMD, including our investigational mini-
dystrophin gene therapy program. In addition, we are involved in efforts focused on
optimizing drug development for DMD. We intend to share data from the phase 2 clinical
study of domagrozumab with the DMD community in order to contribute to the body of
scientific knowledge which may enable the development of new therapies for patients.

In terms of next steps:

  • All clinical sites participating in the domagrozumab DMD studies have been provided with instructions for actions to take with enrolled participants. 

  • Patients and caregivers who have questions regarding their study participation should speak with their study physician for more information. 

  • Pfizer will share additional information about these results with the community when we are able.

We recognize the commitment that the DMD community has provided to these studies
and to our research and development efforts. It is with heartfelt gratitude that we
extend our sincerest ‘thank you’ to all the boys and families who expressed interest in the
study, underwent screening for the study, and to those ultimately participating in the
study. We are also grateful to the advocacy associations and advocates who provided the
tools and support needed for families to engage in clinical research and who continue to
care for the Duchenne community, and to the clinical research sites and staff who
collaborated with us on this important research.

Kind regards,
Michael Binks, MD
Shannon Marraffino
Katherine Beaverson
Rare Disease Research Unit
Pfizer Inc.

PRESS RELEASE

Pfizer Terminates Domagrozumab (PF-06252616) Clinical Studies for the Treatment of Duchenne Muscular Dystrophy

NEW YORK, NY, August 30, 2018 - Pfizer Inc. (NYSE: PFE) announced today that it is
terminating two ongoing clinical studies evaluating domagrozumab (PF-06252616) for the treatment of Duchenne muscular dystrophy (DMD): a Phase 2 safety and efficacy study
(B5161002) and an open-label extension study (B5161004). The Phase 2 study (B5161002), did
not meet its primary efficacy endpoint, which was to demonstrate a difference in the mean
change from baseline in 4 Stair Climb (in seconds) following one year of treatment with
domagrozumab as compared to placebo in patients with DMD. Further evaluation of the totality of evidence including secondary endpoints did not support a significant treatment effect. The
decision comes after a thorough review of data available at the time of the primary analysis,
which evaluated all study participants after one year of treatment, as well as those participants
who were in the trial beyond one year. The studies were not terminated for safety reasons. Pfizer
will continue to review the data to better understand any insights they may provide, and will share results with the scientific and patient community.

“We are disappointed by these results and while we are not progressing with the studies, the
data will contribute to a greater understanding of this disease and we will evaluate the total
data set to see if there is a place for this medicine in muscular diseases,” said Seng Cheng,
PhD, Senior Vice President and Chief Scientific Officer, Pfizer Rare Disease Research Unit.
“We are extremely grateful to all those involved with this trial, especially the boys who
participated, and their families.”

Pfizer is continuing research in DMD and rare neuromuscular diseases, with the goal of bringing
therapies to patients with unmet needs. The company’s continued partnership with advocacy
associations and the community is critical to finding innovative therapies for these diseases.
Pfizer has one ongoing clinical trial in DMD with a gene therapy, PF-06939926, which is an
investigational, recombinant AAV9 capsid carrying a truncated or shortened version of the human
dystrophin gene (mini-dystrophin) under the control of a human muscle specific promotor. 1

About the Domagrozumab Clinical Studies 1
The Phase 2 double-blind, placebo-controlled, multicenter clinical trial investigated the efficacy
and safety of domagrozumab, administered in monthly IV doses, in 121 boys aged 6 to 15 with
DMD, regardless of underlying mutation. It was designed as a two-year, placebo-controlled study
(with the primary analysis after one year); all subjects used background corticosteroid therapy.
The open-label extension study was designed to evaluate long-term safety and efficacy of
domagrozumab.

About Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is a rare, serious, debilitating childhood genetic disease
characterized by progressive muscle degeneration and weakness and significantly shortened life
expectancy. It is the most common form of muscular dystrophy worldwide and primarily affects
boys, with incidence of 1 in every 3500 to 5000 live male births each year. 2 , 3 Children with DMD typically present with signs of weakness, including late walking, trouble getting up, and difficulty running or climbing stairs, usually manifesting in early childhood between the ages of 1 and 4 years. 4 The progressive muscle degeneration leads to a loss of the ability to walk in the early teenage years, on average. Weakness of respiratory muscles ultimately leads to use of mechanical ventilatory support, and weakness in cardiac muscle involvement results in cardiomyopathy.


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