A phase II trial of TGFβ type I receptor inhibitor, galunisertib, plus neoadjuvant chemoradiation in patients with locally advanced rectal cancer

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Background: Transforming growth factor beta (TGFβ) is an immunosuppressive cytokine upregulated in colorectal cancer. Preclinical data demonstrated improved response to chemoradiation with TGFβ blockade in colorectal adenocarcinoma. Here we report the results of our single arm Phase II study combining the TGFβ type I receptor kinase inhibitor, galunisertib, with neoadjuvant chemoradiation in patients with locally advanced rectal adenocarcinoma. Methods: Eligible patients had T3+ or N+ rectal adenocarcinoma planned for surgical resection. Enrolled patients completed a 14-day course of galunisertib, followed by chemoradiation with continuous infusion 5-fluorouracil or capecitabine with radiation to 50.4-54Gy in 28-30 fractions. On day 30, patients underwent another 14-day course of galunisertib concurrent with ongoing chemoradiation. Five to nine weeks after completing neoadjuvant therapy, patients underwent response assessment. Those with complete response by physical exam, proctoscopy, and MRI, could opt for non-operative management and proceed to mFOLFOX6. Those with less than a complete response underwent surgical resection. The primary endpoint was complete response rate (CR), which was a composite of pathologic complete responses in those patients who proceeded to surgery, and clinical complete responses maintained at 1 year after completion of therapy for those who chose non-operative management. Using a Simon Two-Stage approach with 90% power and α = 0.05, to detect a 20% improvement in complete response rate compared to historical control (15% vs 35%); we reject the null hypothesis if ≥10/38 patients have a CR. 38 patients were enrolled with 35 patients evaluable. Results: Median age was 51y, 68% of patients were male, 87% of patients were Stage III, 97% of patients were node-positive, and 97% were proficient in mismatch repair. 95% of patients completed study therapy. Toxicity attributed to galunisertib was Grade 1-2. 28 patients went to surgery, with a mean neoadjuvant rectal (NAR) score (NAR = 5pN-3(cT-pT)+12]2/9.61) of 11.29, and pCR in 7 patients. 7 patients underwent non-operative management, with 5 achieving cCR at 1 year. Therefore, complete responses were observed in 12 patients. Peripheral immune monitoring revealed percent change in CD3+CD4-CXCR3+ T cells and activated CD8EM T cells correlated with response to therapy. 2y PFS and OS were 81.5% and 97%. Conclusions: The addition of TGFβ inhibition to neoadjuvant chemoradiation in locally advanced rectal cancer markedly improved response to therapy, was well tolerated, and warrants further investigation. Clinical trial information: NCT02688712.

Laparoscopic Lavage in the Management of Hinchey III/IV Diverticulitis

Diverticulitis manifestations may cover a spectrum of mild local inflammation to diffuse feculent peritonitis. Up to 35% of patients presenting with diverticulitis will have purulent (Hinchey grade III) or feculent (Hinchey grade IV) contamination of the abdomen, with a high-associated morbidity and mortality. Surgical management may involve segmental resection with or without restoration of bowel continuity. However, emergency resection for diverticulitis can be associated with high mortality rates, as well as low stoma reversal rates at 1 year. Therefore, laparoscopic peritoneal lavage has been proposed for use in selected patients with purulent peritonitis. The topic of laparoscopic peritoneal lavage for the treatment of perforated diverticulitis in the literature has been controversial. Our review of the recent data show that laparoscopic lavage may be safe and feasible in select patients with similar rates of mortality and major morbidity. There is, however, a concern regarding an associated higher rate of postoperative abscess and early reintervention risk.

TGFβ suppresses CD8+ T cell expression of CXCR3 and tumor trafficking

Transforming growth factor beta (TGFβ) is a multipotent immunosuppressive cytokine. TGFβ excludes immune cells from tumors, and TGFβ inhibition improves the efficacy of cytotoxic and immune therapies. Using preclinical colorectal cancer models in cell type-conditional TGFβ receptor I (ALK5) knockout mice, we interrogate this mechanism. Tumor growth delay and radiation response are unchanged in animals with Treg or macrophage-specific ALK5 deletion. However, CD8αCre-ALK5flox/flox (ALK5ΔCD8) mice reject tumors in high proportions, dependent on CD8+ T cells. ALK5ΔCD8 mice have more tumor-infiltrating effector CD8+ T cells, with more cytotoxic capacity. ALK5-deficient CD8+ T cells exhibit increased CXCR3 expression and enhanced migration towards CXCL10. TGFβ reduces CXCR3 expression, and increases binding of Smad2 to the CXCR3 promoter. In vivo CXCR3 blockade partially abrogates the survival advantage of an ALK5ΔCD8 host. These data demonstrate a mechanism of TGFβ immunosuppression through inhibition of CXCR3 in CD8+ T cells, thereby limiting their trafficking into tumors.

Unique surgical approach to a twisted ileal-anal pouch

Total proctocolectomy with ileal pouch-anal anastomosis can restore gastrointestinal continuity in patients requiring colectomy for ulcerative colitis, however, it can be associated with high morbidity. Reoperation for pouch-related complications is technically challenging and often leads to deterioration of pouch function or need for permanent stoma. We report a case of acute on chronic small bowel obstruction secondary to a 360-degree twist in the small bowel introduced during creation of the ileal-anal pouch. Our novel approach at repair has not been reported in past literature which included resection and re-anastomosis of the small bowel proximal to the pouch allowing for pouch salvage with return to function.