First Patient With Breast Cancer Dosed With Samuraciclib Plus ARV-471

The first patient has been dosed in a phase 1b/2 trial evaluating a combination of two novel drugs, samuraciclib and ARV-471 (vepdegestrant) for patients with estrogen receptor (ER)-positive and HER2-negative metastatic breast cancer who previously received a CDK4/6 inhibitor, according to a press release from Carrick Therapeutics, the manufacturing company of samuraciclib.

There is an estimated enrollment of 67 patients, the listing from ClinicalTrials.gov stated. Two arms are included in the trial, in which patients in the first arm receive the treatment combination of samuraciclib and ARV-471 and patients in the second arm receive either ARV-471 alone or samuraciclib alone. For both arms, all patients receive cycles lasting 28 days, according to the listing.

Samuraciclib is an oral treatment that inhibits CDK7 and has potential cancer-fighting activity, the National Cancer Institute defines. By inhibiting CDK7, the drug may prevent the growth of the tumor and may also help destroy cancer cells.

ARV-471 is another oral treatment that is also a selective ER alpha-targeted protein degrader, which uses a technology called proteolysis targeting chimera (PROTAC) with potential anti-cancer activity, according to the National Cancer Institute.

This particular drug recently received a Fast Track designation by the Food and Drug Administration in early February for patients with ER-positive, HER2-negative locally advanced or metastatic breast cancer who previously received endocrine therapy, according to Pfizer, the co-manufacturer of the drug with Arvinas.

The trial aims to evaluate two aspects, in which phase 1b of the study will identify the appropriate doses for samuraciclib and ARV-471 in combination. Phase 2 of the study will enroll additional patients to evaluate the safety and efficacy of the appropriate doses for the treatment combination.

“We’re excited to expand clinical development of samuraciclib with our Phase 1b/2 clinical trial evaluating the combination of samuraciclib and [ARV-471], another step forward in addressing an important need for patients with advanced breast cancer,” Tim Pearson, chief executive officer of Carrick Therapeutics, said in the press release.

READ MORE: First Patient With Breast Cancer Subset Receives Samuraciclib Plus Orserdu

Regardless of the trial’s phase, the primary outcomes researchers will be measuring include drug interaction, the objective response rate (ORR; percentage of patients who have evidence of their tumor shrinking or completely going away) and the effect of samuraciclib on ARV-471, according to ClinicalTrials.gov.

Secondary outcomes the researchers will be measuring include safety and tolerability of the samuraciclib-vapdegestrant combination, specifically noting the type of side effects patients may experience, frequency, intensity, timing, severity and the relationship between the side effects to the treatment combination, the listing reports.

Other secondary outcomes that will be evaluated during the trial are ORR, duration of response (DOR; how long patients have partial or complete stable disease before worsening or death) and progression-free survival, which is the time during and after treatment when a patient lives with cancer without it worsening, the National Cancer Institute defines.

“We believe there is great potential for this combination treatment, based on the encouraging initial clinical trial data for [ARV-471] and Pfizer’s deep expertise in developing treatments for breast cancer,” Pearson said.

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