risovalisib (CYH33)

P1, N=24, Terminated, Haihe Biopharma Co., Ltd. | N=350 --> 24 | Recruiting --> Terminated; Business decision

Even with the recently developed maintenance therapies using molecular targeted inhibitors for ovarian cancers, such as bevacizumab or poly (ADP-ribose) polymerase (PARP) inhibitors, the prognosis of non-HGSC ovarian cancers is unsatisfactory. Through C-CAT database analysis, we estimated that approximately 40% of the patients with OCCC harbored at least 1 of the 17 PIK3CA hotspot mutations designated in the CYH33-G201 trial. JGOG will continue the challenge of establishing novel treatment strategies for rare refractory cancers that will benefit patients suffering from gynecological malignancies, especially those who do not receive satisfactory standard treatment and care.

Moreover, CDK4/6 inhibitors sensitized resistant ESCC cells and PDXs to CYH33. These findings provided mechanistic rationale to evaluate PI3Kα inhibitors in ESCC patients harboring amplified CCND1 and the combined regimen with CDK4/6 inhibitors in ESCC with proficient Rb.

Among 36 patients harboring PIK3CA mutations, 28 patients were evaluable for response, the confirmed objective response rate was 14.3% (4/28). In conclusion, CYH33 exhibits a manageable safety profile and preliminary anti-tumor efficacy in solid tumors harboring PIK3CA mutations.

P2, N=86, Recruiting, Haihe Biopharma Co., Ltd. | Not yet recruiting --> Recruiting | N=228 --> 86

We performed genome-wide gain-of-function screening with a CRISPR-SAM library and identified enhancer of zeste homolog 2 (EZH2) rendering ESCC cells resistant to the PI3Kα inhibitor CYH33...Taken together, our study demonstrated that an EZH2-p21-RB axis remodeled cell cycle regulation and rendered resistance to PI3Kα inhibitors in ESCC. Simultaneously targeting PI3Kα and EZH2 may provide an effective strategy for ESCC therapy with high expression of EZH2.

A novel clinical PI3Kα-selective inhibitor CYH33 possessed superior activity against BCL compared to the marketed PI3Kα-selective inhibitor Alpelisib and PI3Kδ-selective inhibitor Idelalisib. An unbiased screening with drugs approved or in clinical trials for the therapy of BCL identified that the clinical BET (Bromodomain and Extra Terminal domain) inhibitor OTX015 significantly potentiated the activity of CYH33 against BCL in vitro and in vivo, which was associated with enhanced inhibition on c-MYC expression and induction of cell cycle arrest and apoptosis. Our findings provide the rationale of combined CYH33 with BET inhibitors for the therapy of B cell lymphoma.

P2, N=228, Not yet recruiting, Haihe Biopharma Co., Ltd.

CYH33 induces immune activation and synergizes with FASN inhibitor to further promote the antitumor immunity, which gains novel insights into how PI3K inhibitors exert their activity by modulating TME and provides a rationale for the concurrent targeting of PI3K and FASN in breast cancer treatment.

P1, N=228, Not yet recruiting, Haihe Biopharma Co., Ltd.

Furthermore, elevated mTORC1, mitogen-activated protein kinase (MAPK), and c-Myc signaling pathways were found in resistant cells by RNA sequencing and combination of CYH33 and RAD001, MEK162, or OTX015 overcame the resistance to CYH33, which was accompanied with enhanced inhibition on S6, extracellular signal-regulated kinase 1 (ERK), or c-Myc, respectively. Overall, we characterized the adaptations to PI3Kαi in ESCC cells and identified combinatorial regimens that may circumvent resistance.

Western blot analysis confirmed that compound 37 could inhibit phosphorylation of AKT in human cancer cells to modulate the cellular PI3K/AKT/mTOR pathway. And further evaluation in vivo against SKOV-3 xenograft models demonstrated that a dose-dependent antitumor efficacy was achieved.

P1, N=350, Recruiting, ShangHai HaiHe Pharmaceutical

The first-in-human study of the PI3Kα selective inhibitor CYH33 demonstrated a manageable safety profile, linear PK, and encouraging preliminary anti-tumor activity. CYH33 single agent and in combination with other anti-tumor agents have be planned in future studies. Research Funding: Shanghai HaiHe Pharmaceutical Co.,Ltd