The US Food and Drug Administration (FDA) has granted Cellectis’s CLLS52 (alemtuzumab) an orphan drug designation for use in a type of leukaemia, as the company touts positive results from a Phase I trial.

The designation is for the use of CLLS52 as part of the lymphodepletion regimen associated with a different CAR-T therapy by Cellectis, UCART22, in patients with relapsed/refractory B cell acute lymphoblastic leukaemia (ALL), as per a 1 August press release.

Alemtuzumab is manufactured by Sanofi, under the brand names Campath and Lemtrada for chronic lymphocytic leukaemia (CLL) and multiple sclerosis (MS), respectively. Campath was withdrawn from markets in 2012 to make way for Lemtrada and prevent cheaper off-label use. Lemtrada is currently available only through a restricted programme due to its risks of autoimmunity, infusion reactions, and malignancies.

Sanofi agreed to supply the drug to support Cellectis’s clinical trials as part of a May 2021 agreement. At the time, the companies said they would also enter discussions to carry out commercial supply of alemtuzumab under agreed-upon financial conditions.

Cellectis used CLLS52 in a Phase I BALLI-01 trial (NCT04150497) as part of a lymphodepletion regimen, along with fludarabine and cyclophosphamide – named an FCA regimen. Cellectis was investigating its asset UCART22, which was also administered intravenously after a lymphodepletion regimen to determine the maximum tolerated dose and recommended Phase II dose. UCART22 has also been granted an orphan drug designation by the European Commission (EC).

Manufactured from healthy donor cells, UCART22 expresses anti-CD22, a cell surface molecule often found on cancer cells. The UCART22 product has the CD52 gene inactivated to render it resistant to anti-CD52 antibodies such as alemtuzumab. Cellectis reported the trial showed positive preliminary efficacy and safety results in August 2023.

Cellectis chief medical officer Mark Frattini said: “The addition of this lymphodepletion agent [alemtuzumab] to the fludarabine and cyclophosphamide regimen was associated with sustained lymphodepletion and significantly higher UCART22 cell expansion allowing for greater clinical activity.”

Cellectis is busy working on up to ten new cell and gene therapy products as a result of an equity investment and research partnership with AstraZeneca in November 2023. The investment, which concluded in May this year, means the big pharma now has a total equity stake of 44% in Cellectis.

Cell & Gene Therapy coverage on Pharmaceutical Technology is supported by Cytiva.