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| MACI Image courtesy :Vericel Corporation |
VericelCorporation[1], that
develops, manufactures, and markets autologous cell-based therapies for
patients with serious diseases and conditions made a very important
announcement recently that the U.S. Food and Drug Administration (FDA) has
approved MACI® (autologous cultured chondrocytes on porcine collagen
membrane) for the repair of symptomatic single or multiple full-thickness
cartilage defects of the knee with or without bone involvement in adults.
As Per FDA “Maci is the first FDA-approved
product that applies the process of tissue engineering to grow cells on
scaffolds using healthy cartilage tissue from the patient’s own knee.”[2]
The
prevalence rate for cartilage defects in knee is reported at 63% in patients
undergoing arthroscopies. It is a very common problem in adults and the current
definitive treatment is knee replacement surgery.
MACI is
a third-generation autologous chondrocyte implant intended to treat cartilage
defects in the knee. The chondrocytes are placed on bio-absorbable porcine
derived collagen membrane that is than tailored to the site of defect in the
knee.
Each
Maci implant consists of a small cellular sheet containing 500,000 to 1,000,000
chondrocytes per cm2 (about 0.16 square inches). The amount of Maci
administered correlates with the denuded bone area, the size of the cartilage
defect, and is trimmed to ensure that the damaged area is completely covered.
Multiple implants may be used if there is more than one defect.
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| How MACI acts. courtesy Vericel Corporation |
"The treatment of articular cartilage
defects in the knee is challenging because articular cartilage in adults has
minimal capacity to repair itself," said David Recker, MD, chief medical
officer of Vericel. "While orthopedic surgeons have long understood
that autologous chondrocyte implantation can regenerate cartilage tissue, the
previous surgical procedure was technically complex and time consuming, and the
indicated patient population was limited.”
At present
the company has its two products in US market, Carticel and Epicel. Carticel is the world’s
first cellular product in use by surgeons since 1995. It is created from a
patient’s own chondrocytes and has shown to be effective for 4 years. It is
currently in use for symptomatic cartilage defects of the femoral condyle
(medial, lateral or trochlea) caused by acute or repetitive trauma.
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| Image courtesy :Vericel Corporation |
Articular
cartilage damage is caused by repetitive and acute trauma resulting in swelling,
locking and effusion progressing to
debilitating joint pain, dysfunction, and osteoarthritis if left
untreated. The avascular nature of the
cartilage makes regeneration and repair difficult after the damage is done.
The FDA
approval is based on the result of Superiority of MACI
implant versus Microfracture Treatment in patients with
symptomatic articular cartilage defects in the knee (SUMMIT) trial, a Phase 3
two‑year, prospective, multicenter, randomized, open-label, parallel-group
study that recruited a total of 144 patients, ages 18 to
54 years, with at least one symptomatic Outerbridge Grade III
or IV focal cartilage defect on the medial femoral condyle, lateral
femoral condyle, and/or the trochlea.
The study
demonstrated a statistically significantly (p=0.001) greater improvement in
KOOS pain and function (SRA) scores in the MACI group compared to the
microfracture group at two years. Patients from the two-year SUMMIT study
had the option to enroll in a three-year follow-up study (extension
study). Most the patients who completed the SUMMIT study also
participated in the extension study. Overall efficacy data support a
long-term clinical benefit from the use of MACI in patients with cartilage
defects of the knee.
David Recker
added further “MACI is the first product to show a statistically significantly
greater improvement in Knee injury and Osteoarthritis Outcome Score (KOOS) pain
and function scores compared to microfracture, a commonly performed alternative
surgical treatment for cartilage repair, in a well-controlled Phase 3 clinical
study. With the introduction of MACI, orthopedic surgeons will have a
simplified treatment option available for a broader patient population supported
by solid clinical evidence.”
The
most common side effects reported by patients in the trial are arthralgia, flu
like symptoms, joint swelling and back pain. The surgeons need to take many
precautions including patient education before MACI is used. The patients also
need to comply by registering for a rehabilitation program post operatively.
