MorphoSys has presented clinical data from the Phase II COSMOS trial, which evaluated MOR208 in combination with the cancer drug idelalisib in patients with relapsed or refractory chronic lymphocytic leukaemia (CLL) and small lymphocytic lymphoma (SLL).
Hemato-oncological drug candidate MOR208 is an investigational Fc-enhanced humanised monoclonal antibody directed against CD19 in clinical development for the treatment of B-cell malignancies.
MorphoSys chief development officer Dr Malte Peters said: “We are encouraged by the initial and, for the most part, still ongoing responses observed in this heavily pretreated patient population in our exploratory trial with MOR208 plus idelalisib.
“Overall, this shows the potential medical application of MOR208 in additional B-cell malignancies. The data shows that MOR208 may be combined with other cancer drugs used in haematological malignancies, including PI3K inhibitors.
“We look forward to the upcoming results from the second cohort of MOR208 plus venetoclax of our ongoing COSMOS study, which we expect later this year.”
The two-cohort, open-label, multi-centre study COSMOS evaluated the preliminary safety and efficacy of MOR208 combined with idelalisib (cohort A) or venetoclax (cohort B) in patients with r/r CLL/SLL who were earlier treated with Bruton’s Tyrosine Kinase inhibitor (BTKi) ibrutinib.
The trail enrolled 11 patients into cohort A, who had received a median of five prior treatment lines.
Nine out of them had discontinued prior ibrutinib treatment due to progressive disease and two patients due to toxicity.
Based on the preliminary efficacy analysis conducted by the investigators, the overall response rate (ORR) was found to be 82%, including one complete response (CR, 9%) confirmed by bone marrow biopsy and eight partial responses (PR, 73%).
Additionally, two patients (18%) showed stable disease.
CD19 is broadly and homogeneously expressed across different B cell malignancies, including DLBCL and CLL.
It is said to improve B-cell receptor (BCR) signalling, which is assumed important for B-cell survival.