Pact Pharma enrolls first patients in Phase Ia/Ib solid tumor cell therapy study

The company’s product is a T-cell receptor therapy, or TCR. While TCRs have been restricted by genotype, Pact says it has engineered its cells to overcome that restriction.

A company developing cell therapies in oncology has started dosing patients in an early-stage clinical trial of a product candidate designed to be targeted to proteins in cancer cells unique to each patient.

South San Francisco, California-based Pact Pharma said it had begun dosing patients in the Phase I study of NeoTCR-P1, in addition to presenting data at the American Association for Cancer Research’s Special Conference on Immune Cell Therapies for Cancer.

“These exciting results open a bold new frontier for directing a person’s own immune system to treat patients with solid cancers, an area that hasn’t yet seen the successes of immune cell therapies that we have seen for blood cancers,” said Pact CEO Alex Franzusoff, in a statement. “While it is early, the results demonstrate the possibility for Pact’s approach to ignite a patient’s immune response directly against their unique tumor mutation signature, within a clinically relevant timeframe, with potential applicability to most cancers and all ethnicities across the globe.”

That approach is known as a T-cell receptor, or TCR therapy. Both cell therapies currently on the market – Novartis’ Kymriah (tisagenlecleucel) and Gilead Sciences’ Yescarta (axicabtagene ciloleucel) – are chimeric antigen receptor T-cell, or CAR-T therapies. A key distinction between CAR-Ts and TCRs is that while CAR-Ts attack proteins known as antigens on the surface of cancer cells, TCRs can attack proteins inside of cells. A number of companies have been exploring TCRs, especially in solid tumors, such as U.K.-based Adaptimmune and CAR-T companies like Gilead’s Kite Pharma subsidiary and Juno Therapeutics, part of Celgene.

Another difference between CAR-Ts and TCRs is less favorable. TCRs are human leukocyte antigen (HLA)-restricted, meaning they will only work in people with specific genetic makeups and may be restricted by ethnic background. It’s for the same reason that organ and bone marrow transplants depend on finding suitable donors.

However, in an email, a spokesperson for Pact wrote that the company has created systems to address a broad spectrum of HLAs in the global population, thereby allowing its TCRs to work in patients regardless of ethnicity.

The Phase Ia/Ib study, which initiated on July 3, is designed to enroll 148 patients at six sites in California and is currently recruiting at the City of Hope cancer hospital in Duarte, near Los Angeles. Other sites, which are not yet recruiting, include the University of California Los Angeles, UC Irvine, UC Davis, UC San Diego and UC San Francisco. Patients with melanoma, urothelial carcinoma, ovarian cancer, colorectal cancer, breast cancer and prostate cancer are eligible and will receive NeoTCR-P1 as a single agent or with Bristol-Myers Squibb’s PD-1 checkpoint inhibitor Opdivo (nivolumab).

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