Clinigen’s Aldesleukin Earns FDA’s Orphan Drug Designation as ALS Treatment

The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to Clinigen’s aldesleukin for the treatment of amyotrophic lateral sclerosis (ALS).

Aldesleukin is a lab-made version of the interleukin 2 (IL-2), an immune signalling molecule known to play a key role in the maintenance of a type of immune cells called regulatory T-cells, or Tregs. These cells act as negative regulators and shut down excessive immune responses triggered by T-cells, maintaining a healthy immune balance.

Previous research has shown that a shift toward an increase in pro-inflammatory T-cells in detriment of Tregs was linked with ALS severity and progression. This suggests that boosting the numbers and function of Tregs may slow ALS progression and lessen disease severity.

Aldesleukin is marketed under the brand name Proleukin (originally developed by Novartis and now marketed by Clinigen) for the treatment of metastatic renal cell carcinoma (mRCC) and metastatic melanoma. But, when administered at much lower doses than those used for cancer treatment, aldesleukin is capable of boosting Treg function in certain auto-immune and inflammatory disease states.

The ongoing Phase 2 MIROCALS clinical trial (NCT03039673) is assessing the effectiveness and safety of low-dose aldesleukin in improving survival and lessening functional decline of individuals with newly diagnosed ALS.

Participants assigned randomly to receive a placebo or low-dose aldesleukin, delivered as under-the-skin (subcutaneous) injections, in addition to oral riluzole, an approved treatment for ALS marketed as Rilutek by Sanofi and Tiglutik by ITF Pharma.

Each aldesleukin treatment course lasts five days (one sub-cutaneous injection per day for five consecutive days), a regiment that is repeated every four-weeks throughout 18 months.

The study is planned to end in the summer of 2021, with results expected later that year.

Orphan drug status was established to encourage therapies for rare and serious diseases, through benefits such as seven years of market exclusivity and exemption from FDA application fees.

“The Orphan Drug Designation issued by the FDA recognizes the potential of aldesleukin as a possible valuable new treatment for patients with ALS where there is a significant level of unmet need within the disease area,” Shaun Chilton, group chief executive officer of Clinigen, said in a press release.

“Clinigen is also exploring the use of aldesleukin in several other therapeutic areas where its modulatory effects on Tregs may have a beneficial clinical effect,” he added.