Novartis data upsetting the CAR-T at AACR?

Shares in companies developing much-anticipated CAR-T category of immuno-oncology therapies have been under pressure after new data from Novartis was deemed disappointing.

The results of a six-patient study of Novartis' CAR-T-meso candidate in mesothelioma, pancreatic, and ovarian carcinoma reported at the American Association for Cancer Research (AACR) Conference in Philadelphia - did not show any responses to the treatment.

Despite the fact that the trial was tiny and was in its very early stages - and also that four of the six patients seemed to have stable disease whilst on therapy - the results had a negative effect on other companies developing CAR-T therapies. Juno Therapeutics, Kite Pharma and Ziopharm Oncology all traded lower, even though they were not presenting data at the meeting.

CAR-T (chimeric antigen receptor T-cell) treatments, which focus on engineering a patient's own immune cells to be more effective at identifying and destroying malignant cells, are one of the hottest topics in the field of immuno-oncology along with checkpoint inhibitors such as Merck & Co's Keytruda (pembrolizumab) and Bristol-Myers Squibb's Opdivo (nivolumab).

The phase I trial of CART-meso showed that patients "tolerated the treatment well, and there was evidence that the infused immune cells persisted in the patients' blood circulation and successfully migrated to ... tumour sites," according to clinical investigator Janos Tanyi of the University of Pennsylvania.

The trial enrolled patients with tumours that expressed the mesothelin antigen, and subsequent analysis will look at engraftment and persistence of the CAR-T-meso cells as well as anti-tumour responses.

Investors' reaction could reflect the fact that other plays in immuno-oncology -particularly the checkpoint inhibitors - have resulted in consistently positive clinical newsflow.

CAR-T therapies have shown promising activity in haematological cancers - including Novartis' own CTL019 which is in Phase II testing for acute lymphoblastic leukaemia (ALL) - but solid tumours are thought to be a tougher nut for the cell-based therapies to crack. Clearly, efficacy in solid tumours will also massively increase the target market.

"CAR T-cell technology is a promising arm of adoptive immunotherapy," said Tanyi said. "Our long-term goal is to develop a new generation of CART-meso cells that can persist in the patients for years so that, besides eliminating cancer cells, they could also prevent recurrence of the disease."