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PRN 1008, Rilzabrutinib

CAS 1575591-66-0



MW 665.7597


Anti-inflammatory disease, Autoimmune disease treatment

  • OriginatorPrincipia Biopharma
  • Class2 ring heterocyclic compounds; Amines; Anti-inflammatories; Fluorobenzenes; Nitriles; Phenyl ethers; Piperazines; Piperidines; Pyrazoles; Pyrimidines; Skin disorder therapies; Small molecules
  • Mechanism of ActionAgammaglobulinaemia tyrosine kinase inhibitors
  • Orphan Drug StatusYes – Idiopathic thrombocytopenic purpura; Pemphigus vulgaris
  • Phase IIIIdiopathic thrombocytopenic purpura; Pemphigus vulgaris
  • Phase IIAutoimmune disorders
  • 02 Jun 2021Efficacy data from a phase IIa trial in Ankylosing spondylitis presented at the 22nd Annual Congress of the European League Against Rheumatism (EULAR-2021)
  • 07 Apr 2021Sanofi initiates enrollment in a phase I pharmacokinetics trial in healthy volunteers in Australia (PO, Tablet, Capsule) (NCT04748926)
  • 31 Mar 2021Sanofi announces intention to seek regulatory approval for Idiopathic thrombocytopenic purpura in 2023 (Sanofi pipeline, May 2021)


Sanofi to acquire BTK inhibitor firm Principia for $3.7 billion

Principia is testing its small-molecule compounds in multiple sclerosis and immune system diseases

Sanofi will pay $3.7 billion to acquire Principia Biopharma, a San Francisco-based biotech firm developing small molecules that inhibit Bruton tyrosine kinase (BTK). The price represents about a 75% premium over Principia’s stock market value in early July, before reports surfaced that Sanofi was interested in buying the firm.

BTK is a protein important for both normal B cell development and the proliferation of lymphomas, which are B cell cancers. AbbVie, AstraZeneca, and BeiGene all market BTK inhibitors for treating specific kinds of lymphomas. Sales of AbbVie’s inhibitor, Imbruvica, approached $4.7 billion in 2019.

Other drug firms have been eager to get in on the action as well. In January, Merck & Co. spent $2.7 billion to acquire ArQule, whose experimental noncovalent BTK inhibitor is designed to overcome resistance that some cancers develop after treatment with current covalent BTK inhibitors. Eli Lilly and Company’s $8 billion acquisition of Loxo Oncology in 2019 also included a noncovalent BTK inhibitor.

BTK is also linked to inflammation, and Principia focuses on developing BTK inhibitors for immune system diseases and multiple sclerosis. Its compound rilzabrutinib is currently in clinical trials for pemphigus and immune thrombocytopenia. In 2017, Sanofi struck a deal to develop Principia’s brain-penetrant BTK inhibitor, SAR442168, for multiple sclerosis.

Sanofi announced in April of this year that the inhibitor reduced formation of new lesions—the scarred nervous tissue that gives multiple sclerosis its name—by 85% in a Phase II clinical trial. A Phase III trial of the compound began in June.

Upon announcing its deal to acquire Principia, Sanofi said that both rilzabrutinib and SAR442168 have the potential to become a “pipeline in a product,” indicating they can be used for many immune-related and neurological diseases, respectively.

The anti-inflammatory effects of BTK inhibitors have raised interest in the drugs as treatments for people hospitalized with COVID-19. Notably, the US National Cancer Institute conducted a small study suggesting acalabrutinib may help reduce the respiratory distress and inflammation in people with COVID-19. Based on that preliminary study, AstraZeneca—which markets acalabrutinib as Calquence—is conducting a 60-person randomized trial of the drug for COVID-19.

Sanofi has not indicated interest in investigating Principia’s BTK inhibitors as COVID-19 treatments.


WO2014039899, Example 31

Rilzabrutinib (PRN1008) is an oral, reversible covalent inhibitor of Bruton’s tyrosine kinase (BTK) [1].

Example 31
Synthesis of (R)-2-(3-(4-amino-3-(2-fluoro-4-phenoxyphenyl)- 1 H-pyrazolo[3,4-d]pyrimidin- 1 -yl)piperidine- 1 -carbonyl)-4-methyl-4-(4-(oxetan-3-yl)piperazin- 1 -yl)pent-2-enenitrile
Figure imgf000087_0002
Step 1
A solution of 2-bromo-2-methyl-propanal (696.6 mg, 4.61 mmol) in DCM (10 mL) was cooled with an ice bath and l -(oxetan-3-yl)piperazine (328 mg, 2.31 mmol), diluted with 5-10 mL of DCM, was slowly added via addition funnel over a 15 min period. Next, Hunig’s base (0.4 mL, 2.31 mmol) was added and then the cooling bath was removed. The reaction mixture was stirred at room temperature overnight and the DCM layer was washed three times with 0.5N HC1. The combined aqueous layer was neutralized with NaOH to pH 10-11 and extracted with DCM. The combined organic layer was washed with brine and dried over Na?S04. Filtration and removal of solvent afforded 2-methyl-2-[4-(oxetan-3-yl)piperazin-l- yl]propanal as a light yellow liquid, which was used directly in the next step without further purification.
Step 2
To a cooled (0 °C) solution of 3-[(3R)-3-[4-amino-3-(2-fluoro-4-phenoxy-phenyl)- pyrazolo[3,4-d]pyrimidin-l-yl]-l-piperidyl]-3-oxo-propanenitrile (80 mg, 0.17 mmol), was added 2-methyl-2-[4-(oxetan-3-yl)piperazin-l-yl]propanal (-108 mg, 0.51 mmol) in DCM (10 mL) followed by pyrrolidine (0.08 mL, 1.02 mmol) and TMS-C1 (0.09 raL, 0.68 mmol.) The ice bath was removed, and the reaction stirred 1 hour. Most of the solvent was removed and the residues were purified by chromatography, using 95:5 CH2Cl2:MeOH to obtain 79 mg of (R)-2-(3-(4-amino-3-(2-fluoro-4-phenoxyphenyl)-lH-pyrazolo[3,4-d]-pyrimidin-l- yl)piperidine- 1 -carbonyl)-4-methyl-4-(4-(oxetan-3-yl)piperazin- 1 -yl)pent-2-enenitrile as a white solid. MS (pos. ion) m/z: 666 (M+l).


Therapy based on Bruton’s tyrosine kinase (BTK) inhibitors one of the major treatment options currently recommended for lymphoma patients. The first generation of BTK inhibitor, Ibrutinib, achieved remarkable progress in the treatment of B-cell malignancies, but still has problems with drug-resistance or off-target induced serious side effects. Therefore, numerous new BTK inhibitors were developed to address this unmet medical need. In parallel, the effect of BTK inhibitors against immune-related diseases has been evaluated in clinical trials. This review summarizes recent progress in the research and development of BTK inhibitors, with a focus on structural characteristics and structure-activity relationships. The structure-refinement process of representative pharmacophores as well as their effects on binding affinity, biological activity and pharmacokinetics profiles were analyzed. The advantages and disadvantages of reversible/irreversible BTK inhibitors and their potential implications were discussed to provide a reference for the rational design and development of novel potent BTK inhibitors.

Image 17

///////////////PRN-1008,  PRN 1008, Rilzabrutinib, リルザブルチニブ,

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