Alteogen to diversify indications of ADC candidate in phase 2 trial

Alteogen released the phase 1 clinical trial results of antibody-drug conjugate (ADC) to treat breast cancer.

As the company confirmed the safety and efficacy of the drug candidate in the phase 1 study, it will diversify indications in the phase 2 study and seek an opportunity to license it out.

In a public filing on Tuesday, Alteogen disclosed the results of phase 1 local study of ALT-P7, a treatment candidate for HER2-positive breast cancer. ALT-P7 is a targeted therapy for HER2-positive breast cancer developed with Alteogen’s ADC technology.

The company evaluated the safety, pharmacokinetics, and anticancer effects of ALT-P7 in patients with advanced or recurrent HER2-positive breast cancer who had failed the standard treatment. Twenty-seven subjects who participated in the study were end-stage cancer patients who received up to six types of systemic chemotherapy, including four types of prior HER2 targeted therapy on average.

Alteogen obtained the regulatory nod for the phase 1 trial in June 2017 and began the study on Jan. 11, 2018. The trial took place at Gachon University Gil Medical Center and Samsung Medical Center.

The phase 1 trial was an open, single-group study where eight dose groups received gradually increased doses. The trial participants received two or more injections with an interval of 21 days.

Alteogen said the phase 1 results proved ALT-P7’s safety and efficacy. In addition, the phase 1 data showed that the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) were set at 4.5 mg/kg, the company said.

According to the company’s public disclosure, ALT-P7’s dose-limiting toxicity (DLT) was 4.8 mg/kg, and a higher dose than the DLT resulted in febrile neutropenia, hyperbilirubinemia, myalgia, and hyponatremia.

In pharmacokinetic evaluation, the study showed that ALT-P7 levels went up along with an increase in dose. No patient demonstrated immunogenicity against ALT-P7 in the phase 1 study, the company said.

Alteogen did not elaborate on the grades and types of adverse reactions.

According to the company’s release of the interim results of the phase 1 trial of ALT-P7 at the meeting of the American Society of Clinical Oncology (ASCO) and that of the Korean Society of Medical Oncology (KSMO) in 2020, four patients experienced neutropenia, a grade 3 to 4 adverse reaction. Other adverse reactions included muscle pain, fatigue, sensory neuropathy, and pruritus.

The company said the disease control rate (DCR), which combines complete response (CR), partial response (PR), and stable disease (SD), was 72 percent (18 out of 25).

Also, the company emphasized that the progression-free survival (PFS) of three participants in cohort seven who received the MTD of 4.5 mg/kg was 6.67±4.01 months.

Alteogen plans to develop ALT-P7 to get three indications – one for breast cancer, one for gastric cancer, and the other for combination therapy. However, the company has yet to provide a time frame for this.

The company’s initial push for a licensing-out deal is not going smoothly.

“Due to the Covid-19 pandemic, discussions for a licensing-out deal are being delayed,” an official at Alteogen said. “We plan to engage in an active negotiation with a multinational pharmaceutical company.”