In a recent news release, biopharmaceutical company FibroGen, Inc. (“FibroGen”) shared that its therapeutic candidate, pamrevlumab, received Fast Track designation from the FDA. The anti-CTGF antibody is designed to treat patients with Duchenne muscular dystrophy (DMD).
Pamrevlumab
Developed by FibroGen, pamrevlumab is a fully human recombinant monoclonal antibody designed to inhibit connective tissue growth factor (CTGF). Let’s break that down a bit. According to the Mayo Clinic, monoclonal antibodies (mABs) are:
laboratory-produced molecules engineered to serve as substitute antibodies that can restore, enhance or mimic the immune system’s [response].
G Biosciences then describes recombinant antibodies as those which can be developed in vitro using synthetic genes. So, in short, fully human recombinant monoclonal antibodies are developed by using some synthetic genes and human antibodies to mimic the immune system and prompt a stronger immune response. In this case, pamrevlumab inhibits CTGF, which, in fibrotic disorders, can play a role in the excess development of fibrotic tissue. Beyond DMD, FibroGen is also exploring pamrevlumab as a potential treatment for locally advanced unresectable pancreatic cancer (LAPC) and idiopathic pulmonary fibrosis (IPF).
Fast Track Designation
Recently, pamrevlumab was granted Fast Track designation. This status came following data from a Phase 2 clinical trial evaluating the treatment for patients with DMD. In addition, FibroGen is currently evaluating pamrevlumab for DMD in two additional Phase 3 clinical trials.
According to the FDA, the Fast Track program:
facilitates the expedited development and review of new drugs or biologics that are intended to: 1) treat serious or life-threatening conditions and 2) demonstrate the potential to address unmet medical needs.
A serious condition is one which inhibits daily function, impacts potential survival or mortality, or could progress into a more serious or fatal condition. In the above link, the FDA explains that serious conditions can be HIV/AIDS, cancer, or Alzheimer’s disease, but also diabetes, epilepsy, or depression. Next, filling an unmet need is defined as offering a therapy or treatment solution which is either better than those available or fills a spot where no current therapy exists.
Once a drug developer receives Fast Track designation, the company also receives a variety of incentives, such as:
- Priority Review and Accelerated Approval eligibility
- More frequent FDA communication and meetings
- Rolling Review for BLAs and NDAs
Duchenne Muscular Dystrophy (DMD)
Duchenne muscular dystrophy (DMD) is a rare inherited genetic disorder and one of the nine forms of muscular dystrophy. Inherited in an X-linked recessive pattern, DMD gene mutations prevent the body from producing enough dystrophin. Normally, dystrophin plays a role in muscle strength, function, and repair. As a result, without dystrophin production, muscles weaken and waste away. 1 in 3500 male births has DMD, while only 1 in around 50 million female births do. Symptoms usually manifest before 6 years old and, by early teens, many patients require additional mobility, cardiac, and respiratory support. Altogether, symptoms include:
- Fatigue
- Enlarged calf muscles
- Progressive muscle weakness beginning in the lower extremities
- Frequent tripping or falling
- Tight joints
- Difficulty walking or moving positions
- Cardiomyopathy (progressive enlargement of the heart)
- Learning and motor skill difficulties
- Scoliosis
- Heart disease
- Respiratory failure
