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Step Pharma Announces Promising Data on the Therapeutic Potential of Selective Small Molecule Inhibition of CTPS1 Presented at the 64th American Society of Hematology Annual Meeting

By December 12, 2022May 23rd, 2023Press Release

Press Release

St. Genis-Pouilly, France, 12 December 2022

  • STP938 shows strong anti-tumour effect in preclinical models of mantle cell lymphoma and multiple myeloma
  • STP938 shows synergistic anti-tumour activity in preclinical models when combined with selective inhibitors of other pathways

St. Genis-Pouilly, France and London, UK, 12 December 2022 – Step Pharma, the world leader in CTPS1 inhibition for the targeted treatment of cancer, today announces that encouraging pre-clinical data on its first-in-class, highly selective, orally bioavailable CTPS1 inhibitor, STP938, were presented at the 64th American Society of Hematology (ASH) Annual Meeting held from the 10-13 December, 2022 in New Orleans, Louisiana and virtually.

The data presented by Step Pharma collaborators demonstrates the potential of STP938, a highly selective CTPS1 inhibitor, as a therapeutic for the treatment of mantle cell lymphoma and multiple myeloma both as a single agent and in combination with other targeted inhibitors.

In pre-clinical models of mantle cell lymphoma, STP938 showed strong anti-tumour effects, which were further enhanced by combined administration with venetoclax, a selective BCL-2 inhibitor currently in clinical development for treatment of this lymphoma type.

Single agent STP938 also showed activity in preclinical models of multiple myeloma and demonstrated strong synergy when combined with an inhibitor of the DNA damage response pathway (ATR, CHEK1 or WEE1).

“We are encouraged by the promising pre-clinical data produced by our collaborators showing the anti-tumour effects of STP938 in mantle cell lymphoma and multiple myeloma models”,

said Andrew Parker, Chief Executive Officer of Step Pharma.

“These data reinforce our conviction that by inhibiting CTPS1, a key component of the pyrimidine synthesis pathway to which all cancers are addicted, STP938 has broad therapeutic potential. We have commenced clinical trials to test the safety and efficacy of STP938 in T cell and B cell lymphomas to bring this potentially lifesaving therapy to patients in our efforts to drive a step change in the way we treat cancer.”

Full details of the poster presentations, which were both presented on Sunday, December 11, 2022 at 6:00 PM-8:00 PM EST in Hall D (Ernest N. Morial Convention Center), are:

Authors: David Chiron, PhD, Emmanuelle Menoret, PhD, Charlotte Kervoelen, PhD, Sophie Maïga, Celine Bellanger, Benoit Tessoulin, MD, Cyrille Touzeau, Hélène Asnagli, PhD, Andy Parker, PhD, Philip Beer, MD, PhD and Catherine Pellat-Deceunynck, PhD

Authors: Christina Pfeiffer, MSc, Alexander Michael Grandits, PhD, Hélène Asnagli, PhD, Anja Schneller, MSc, Julia Huber, MSc, Niklas Zojer, MD, Martin Schreder, MD, Andrew Parker, PhD, Arnold Bolomsky, PhD, Philip Beer, MD, PhD, Heinz Ludwig, MD

Step Pharma also recently entered clinical development with STP938 in a Phase I/II trial for T cell and B cell lymphomas. An abstract outlining the study design was published by ASH in the journal Blood. Full details are:

Authors: Philip Beer, Maureen Higgins, Hélène Asnagli, Eef Hoeben, Michael Hubank, Andrew Parker, Brian Schwartz


Step Pharma
Andrew Parker, Chief Executive Officer

Media Relations
Consilium Strategic Communications
Amber Fennell, Namrata Taak, Stella Lempidaki
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About Step Pharma

Step Pharma’s goal is to bring about a step change in how cancer is treated with targeted therapies that kill cancer cells and leave healthy cells unharmed. The Company is the world leader in CTPS1 inhibition, a new approach with the potential to yield highly selective, safe and effective cancer treatments for both blood cancers and solid tumours.

The Company’s lead product STP938 has received both IND and CTA clearance to proceed into first in human trials in the US and UK for the treatment of T cell and B cell lymphomas. Clinical trials in lymphoma commenced in the second half of 2022. STP938 has the potential to be the backbone of a multitude of cancer therapies as well as a potent monotherapy for hard-to-treat blood cancers.

Step Pharma was founded in 2014 by Kurma Partners, the Imagine Institute and Sygnature Discovery, based on the scientific discoveries of Prof. Alain Fischer and Dr Sylvain Latour. Step Pharma is based in Saint-Genis-Pouilly, France, and is supported by a strong syndicate of investors led by Kurma Partners and including Bpifrance (Fonds Biothérapies Innovantes et Maladies Rares and InnoBio2 Fund), Pontifax, Hadean Ventures, Sunstone Life Science Ventures, Inserm Transfert Initiative, Idinvest, Sygnature Discovery and the Imagine Institute.


About STP938

STP938 is a first-in-class, highly selective, orally bioavailable inhibitor of CTP synthase 1 (CTPS1), a key component of the pyrimidine synthesis pathway. CTPS1 inhibition inhibits the proliferation of neoplastic lymphoid cells and results in cell death. All cancers appear to be addicted to CTPS1 for DNA synthesis. STP938 entered clinical development in September 2022 for the treatment of T cell and B cell lymphoma.