UPDATE: SL-28 Phase 1/2 Trial Started To Recruit in Advanced Solid Tumors

A very interesting Phase 1/2 trial of SL‑28 has started enrolling up to 60 patients with advanced solid tumours at The Southern Oncology Clinical Research Unit (SOCRU). Although the study is open to a broad range of solid cancers, it is particularly noteworthy for prostate cancer because a published case report described a complete response in a man with metastatic, hormone‑sensitive disease treated with SL‑28 without ongoing androgen deprivation therapy, with PSA falling from 10.4 to 0.1 ng/mL and imaging plus biopsy confirming disappearance of the primary tumour and bone metastases. (You can find our original article here)

SL‑28 is a novel allogeneic donor leukocyte therapy (“Leukocyte‑Tells”) prepared from healthy donors and modulated ex vivo to enhance cancer‑killing activity, phagocytosis, tumour homing and immunomodulatory signalling, without genetic engineering or HLA matching, which is why it is being developed as a pan‑cancer, off‑the‑shelf cell therapy for patients with otherwise refractory solid tumours.

Note: While unrelated to prostate cancer, this information illustrates prior uses of SL-28.

Two additional case reports document SL-28 use in pancreatic cancer and, more recently, non-small cell lung cancer.

A 79-year-old woman with T4N0M1 pancreatic adenocarcinoma and chemotherapy-refractory liver and bone metastases received SL-28 under expanded access. After ~3 months of SL-28 monotherapy, she achieved a RECIST v1.1 partial response with >30% reduction in target lesions, disappearance or shrinkage of several hepatic metastases, regression of femoral and pubic bone lesions, and no serious adverse events reported.

An 82-year-old man with stage IV non-small cell lung cancer and large malignant pleural effusion (>2 L) showed no response after two cycles of etoposide-based chemotherapy. Following SL-28, he progressed from stable disease at 3 weeks to partial response at 8 weeks, and ultimately a RECIST v1.1 complete response by week 22, with disappearance of lung lesions, near-complete resolution of pleural fluid and biopsy-confirmed absence of malignant cells.

Of course, case reports are not per se an index of efficacy in a wider population, but they still provide a valuable clinical signal.

Clinical trial.