On June 1, 2022 Asher Biotherapeutics, a biotechnology company developing precisely-targeted immunotherapies for cancer, autoimmune, and infectious diseases, reported that it has entered into a clinical trial collaboration and supply agreement with Merck (known as MSD outside of the United States and Canada) for a planned Phase 1a/1b dose escalation and expansion trial to evaluate AB248, Asher Bio’s novel investigational CD8-targeted interleukin 2 (IL-2), as a monotherapy and in combination with KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, in patients with locally advanced or metastatic solid tumors, including melanoma, renal cell carcinoma (RCC), non-small cell lung carcinoma (NSCLC) and squamous cell carcinoma of the head and neck (SCCHN) (Press release, Asher Biotherapeutics, JUN 1, 2022, View Source [SID1234615378]). Under the terms of the agreement, Asher Bio is responsible for conducting the Phase 1a/1b trial, which it expects to initiate in the second half of 2022.

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Mechanistically, IL-2 signaling is complementary to PD-1 checkpoint blockade: checkpoint inhibitors release the brakes on T cells, allowing them to kill cancer cells, while IL-2 pushes on the gas pedal driving an increase in the number and activity of T cells. In the clinic, there have been studies conducted on high dose IL-2 as a monotherapy to treat PD-1 failures and on high dose IL-2 in combination with PD-1 checkpoint inhibitors in earlier lines of therapy that both demonstrated encouraging activity. However, despite high dose IL-2 efficacy in these settings, severe toxicities significantly hamper use of IL-2 in practice.

Asher Bio previously reported preclinical data from studies of a murine surrogate of AB248, which achieved significant anti-tumor activity as monotherapy and in combination with anti-PD1, without toxicity associated body weight loss. In comparison, treatment with a "not α" IL-2 achieved lower anti-tumor activity and was accompanied by body weight loss.

"We are looking forward to initiating this trial in collaboration with Merck to evaluate AB248 in combination with KEYTRUDA in a range of cancers," said Craig Gibbs, Ph.D., Chief Executive Officer of Asher Bio. "Treatment with PD-1 checkpoint blockade monotherapy or in combination with chemotherapy or another immunotherapy has become a recommended first line treatment in multiple indications. Yet for patients who failed to achieve a response or who relapse, treatment options are limited. In addition, there is a subset of first line patients where there is an opportunity to enhance the current standard of care. We believe that by precisely focusing the effect of IL-2 to the primary immune cell subset that drives anti-tumor efficacy, AB248 may have the potential to deliver a highly differentiated product profile that could become a backbone of immuno-oncology across a range of solid tumors."

KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc.

About AB248
AB248 is a novel CD8+ T cell selective IL-2, generated by fusing a reduced potency IL-2 mutein to a humanized IgG1 anti-CD8β antibody. It was specifically engineered to selectively and potently expand CD8+ T-cells, while avoiding natural killer (NK) cells, which can act as a pharmacological sink and contribute to toxicity, and regulatory T (Treg) cells, which are immunosuppressive. In some preclinical studies, AB248 exhibits an approximately 1,000-fold preference for the activation of CD8+ T cells over NK cells and Tregs. In other nonclinical studies, AB248 has demonstrated potent anti-tumor activity both alone and in combination with PD-1 checkpoint blockade in a wide variety of murine tumor models.