Investing.com -- Lyell Immunopharma Inc (NASDAQ:LYEL) shares climbed 3% in premarket trading Monday after the company amended its colorectal cancer trial following a reduction in side effects.
The biotechnology company reported that gastrointestinal prophylaxis reduced Grade 2 or higher diarrhea or colitis from 55% without prophylaxis to 10% with prophylaxis in its U.S. Phase 1 clinical trial evaluating LYL273 in patients with relapsed or refractory metastatic colorectal cancer. The company has amended the ongoing Phase 1 trial to enable seamless expansion into a potential pivotal single-arm Phase 2 trial pending regulatory alignment.
As of May 5, 2026, nineteen patients had been enrolled in the U.S. Phase 1 clinical trial across Dose Levels 1 and 2. Ten patients were enrolled under the new gastrointestinal prophylaxis regimen including infliximab, vedolizumab and budesonide, along with a standardized safety management plan. These ten patients did not experience Grade 3 or higher cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome.
The company previously reported a 50% overall response rate across Dose Levels 1 and 2 in third- or later-line relapsed or refractory metastatic colorectal cancer patients. The FDA has granted LYL273 Fast Track designation for the treatment of metastatic colorectal cancer.
The amended trial, now called CARABINER, includes four dose-escalation cohorts at Dose Levels 1 through 4. The amendment adds new cohorts, including a second-line cohort and a cohort evaluating a combination strategy with radiotherapy. Up to sixty patients are expected to be enrolled across the new cohorts.
Lyell expects additional Phase 1 clinical data, including clinical outcomes, and an End-of-Phase 1 FDA meeting in the second half of 2026. The maximum tolerated dose has not yet been determined as dose escalation continues.
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