Targeted cancer radiopharma specialist – ENDOCYTE INC.’s acquisition

By Ajay V. Patil

Endocyte Inc. & ¹⁷⁷Lu-PSMA-617

Endocyte Inc. is a radioligand therapy pharma, particularly known for its potentially first in class radioligand therapy for metastatic castration-resistant prostate cancer (mCRPC) – ¹⁷⁷Lu-PSMA-617. Popular immunotherapy target encoded by ‘folate dehydrogenase I’ gene – Prostate Specific Membrane Antigen (PMSA), differentially expresses in about 80% of mCRPC patients. PSMA-617 selectively delivers the short-range beta-emitting radioactive isotope lutetium or ¹⁷⁷Lu to tumor cells, protecting healthy cells with no PSMA expression.

Phase II and III studies – ¹⁷⁷Lu-PSMA-617

Phase II study with fifty PSMA-positive mCRPC patients treated with ¹⁷⁷Lu-PSMA-617, showed a median prostate specific antigen (PSA) progression free survival (PFS) of 7.6 months (p<0.0001). Study also showed, median overall survival (OS) of 13.5 months – only for the first cohort of 30 patients enrolled (p=0.0201). FDA recently agreed to change the primary endpoint of the ongoing phase III Vision study to ‘radiographic progression-free survival’ (rPFS) instead of OS. Mainly, two interim assessments previously planned at 50 percent and 70 percent of OS events will be replaced with a single assessment of rPFS.

CEO Michael Sherman said, “I think it’s better said that, rPFS on its own could be supportive. And so I guess by definition, it doesn’t necessarily have to correlate in this case to an OS benefit. There are other things that play post-therapy or post-trial therapies that could confound OS”. In a cautious reply he stated, “what the FDA probably says in acknowledging this is – Look, as long as you have this rPFS benefit in the context of an overall favorable risk-benefit assessment, [we] don’t need to see a correlated overall survival benefit”.

Novartis deal

On October 18, 2018, Novartis announced their agreement with Endocyte Inc., to acquire all of its outstanding shares of common stock for USD 24 per share offering equity valuation at USD 2.1 billion. Active component of the therapy – ¹⁷⁷Lu, is also the part of Novartis’s another FDA approved drug for gastroenteropancreatic neuroendocrine tumors – Lutathera. Besides Endocyte Inc., Novartis also acquired Avexis Inc. (with spinal muscular atrophy gene therapy profile) and Spark Therapeutics Inc., in $8.7 billion and $105(up front)+65 million(milestone payments) deals respectively.

With this major acquisition, it will be interesting to follow the development of other innovative products in Endocyte Inc. pipeline including ‘adapter-controlled CAR-T cell therapies’.

References:

1. http://www.bioworld.com/content/endocyte-2b-takeover-novartis-beams-progenics-signal
2. https://www.sciencedirect.com/science/article/pii/S1470204518301980?via%3Dihub
3. https://www.novartis.com/news/media-releases/novartis-announces-planned-acquisition-endocyte-expand-expertise-radiopharmaceuticals-and-build-commitment-transformational-therapeutic-platforms
4. https://endocyte.com/pipeline/

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