Privigen Granted FDA’s Organ Drug Status to Treat Scleroderma as Phase 2 Trial Continues Enrolling Patients

Marta Figueiredo, PhD avatar

by Marta Figueiredo, PhD |

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TLY012 orphan drug status

Privigen — an approved therapy for a range of immune-related conditions — has been granted orphan drug designation by the U.S. Food and Drug Administration (FDA) for the treatment of systemic scleroderma.

Orphan drug designation is given to investigational therapies with the potential to be safe and effective treatments for rare diseases, defined as those affecting fewer than 200,000 people in the U.S.

In October 2019, Privigen — developed by CSL Behring — also earned the FDA’s fast track designation for the same indication.

These designations are expected to provide regulatory support and financial benefits to accelerate Privigen’s clinical development and review. Orphan drug designation also ensures a seven-year period of marketing exclusivity in the U.S. upon regulatory approval.

“CSL Behring is driven by our promise to develop and deliver innovative therapies for patients with the highest unmet need,” Mittie Doyle, MD, a vice president at CSL Behring, said in a press release.

“Receiving orphan drug designation for Privigen as an investigational SSc [scleroderma] therapy is an important milestone in our quest to address the devastating impact of systemic sclerosis [or scleroderma],” she added.

Scleroderma may affect multiple systems and nearly every organ in the body, causing progressive, widespread fibrosis (tissue scarring). Besides the skin, the disease commonly affects the heart, blood vessels, lungs, stomach, and kidneys.

Privigen is an intravenous immunoglobulin (IVIG) therapy, meaning that it delivers specific antibodies purified from healthy people to restore the levels and/or help regulate immune responses in patients.

It is already approved in the U.S. for treating several immune-related conditions, including primary immunodeficiency, chronic immune thrombocytopenic purpura, and chronic inflammatory demyelinating polyneuropathy.

Evidence suggests that Privigen may have both immunomodulatory and anti-fibrotic effects in scleroderma patients.

A pilot clinical trial (NCT01785056) evaluated Privigen’s safety and effectiveness in 14 adults with scleroderma over six months of treatment.

To be included, participants had to have not responded to standard treatment during the four months prior to the trial’s initiation. The study’s goals included assessing whether Privigen led to improvements in skin, lung, muscle, joint, and inflammatory measures. Results of this trial have not yet been announced.

CSL Behring recently initiated a Phase 2 study in the U.S. (NCT04138485) to evaluate the safety and effectiveness of Privigen in up to 144 adults with diffuse scleroderma. Enrollment is still ongoing, and more information on contacts and locations can be found here.

Participants will be randomly assigned to receive either Privigen or a placebo.

The trial’s primary goal is to assess changes in the American College of Rheumatology Combined Response Index in diffuse scleroderma score over 48 weeks.

The score is calculated according to changes from the study’s start in the modified Rodnan Skin score (mRSS) of skin thickness, the Scleroderma Health Assessment Questionnaire-Disability Index (HAQ-DI), forced vital capacity (FVC, a measure of lung function), and patient and physician global assessments of health related to scleroderma.

Secondary goals include the proportion of patients responding to treatment, several effectiveness measures — including the mRSS, HAQ-DI, FVC, among others — and safety assessments.

After completing treatment, participants will have the option to enter an open-label treatment period, in which all patients will receive Privigen for 24 weeks.