SL-28 Phase 1/2 Trial: A Potential Breakthrough for Advanced Solid Tumors

SL-28 is a new type of donor cell therapy called Leukocyte-Tells. These cells come from healthy donors and get prepared outside the body to better fight cancer. They make more cancer-killing compounds, eat tumor cells, release enzymes, produce helpful signals, and move well toward tumors. Unlike other cell therapies, SL-28 does not need to match the patient’s immune markers or change genes. This makes it easier to use and lowers risks like immune attacks on healthy tissue.

A Phase 1/2 open-label trial currently underway in Nedlands, Western Australia, evaluates SL-28’s safety, pharmacokinetics, and preliminary efficacy in patients with advanced unresectable solid tumors, including prostate cancer. The study starts with low doses and increases them safely. Patients get it for 12 weeks, 5 days a week with 2 days off. It checks safety first, then looks at tumor shrinkage using standard scans.

One case shows great results in a 79-year-old man with prostate cancer and bone spread. His cancer did not respond to hormone drugs. SL-28 doses (10 million to 100 million cells per shot, daily for 4 months) dropped his PSA from 10.4 to 0.1 ng/mL. Scans showed the main tumor and bone metastases disappeared, confirmed by biopsy. He only had mild fever that went away. No major side effects happened.

Note: The patient received triptorelin + apalutamide initially but discontinued after 4 weeks due to PSA progression and side effects. He then received SL-28 monotherapy (4 months) then produced complete response, confirmed disease-free at 8 months post-treatment, without requiring castration-level testosterone suppression (through ADT or orchiectomy) typical in prostate cancer trials.
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Early signs point to SL-28 working well in tough cancers, especially prostate cases where it cleared markers and spots fast. More trial results will show the best dose and effects across cancer types.​

Clinical trial.

Case study.