A phase 1b trial of the CXCR4 inhibitor mavorixafor and nivolumab in advanced renal cell carcinoma patients with no prior response to nivolumab monotherapy.

Background The CXCR4 chemokine receptor promotes tumor survival through mechanisms that include suppressing antitumor immune responses. Mavorixafor (X4P-001) is an oral, selective, allosteric CXCR4 inhibitor that decreases the recruitment of immunosuppressive cells into the tumor microenvironment and increases activated cytotoxic Tcell infiltration. Methods Patients with metastatic clear cell renal cell carcinoma (ccRCC) unresponsive to nivolumab monotherapy received oral mavorixafor 400 mg daily plus 240 mg intravenous nivolumab every 2 weeks. Results Nine patients were enrolled, median age 65 years. At baseline 4 had progressive disease (PD) and 5 had stable disease (SD). One of 5 patients with SD at study entry on prior nivolumab monotherapy had a partial response (PR) on combination treatment; all 4 patients with PD at study entry had a best response of SD with the combination treatment (median duration: 6.7 months; range: 3.7-14.7). Four patients discontinued therapy due to treatment-related adverse events (AEs). Grade ≥ 3 drug-related AEs were elevated alanine and aspartate aminotransferase (2 patients each); and autoimmune hepatitis, chronic kidney disease, increased lipase, maculopapular rash, and mucosal inflammation (1 patient each). A robust increase in levels of chemokine (C-X-C motif) ligand 9 CXCL9 on mavorixafor appeared to correlate with clinical benefit. Conclusions The CXCR4 inhibition mediated by mavorixafor, in combination with PD-1 blockade to enhance antitumor immune responses in patients unresponsive to checkpoint inhibitor monotherapy, is worthy of further study. Mavorixafor and nivolumab combination therapy in patients with advanced ccRCC demonstrated potential antitumor activity and a manageable safety profile.Trial registration: ClinicalTrials.gov identifier: NCT02923531. Date of registration: October 04, 2016.

Mavorixafor, an Orally Bioavailable CXCR4 Antagonist, Increases Immune Cell Infiltration and Inflammatory Status of Tumor Microenvironment in Patients with Melanoma.

Purpose: Mavorixafor is an oral, selective inhibitor of the CXCR4 chemokine receptor that modulates immune cell trafficking. A biomarker-driven phase Ib study (NCT02823405) was conducted in 16 patients with melanoma to investigate the hypothesis that mavorixafor favorably modulates immune cell profiles in the tumor microenvironment (TME) and to evaluate the safety of mavorixafor alone and in combination with pembrolizumab. Experimental Design: Serial biopsies of melanoma lesions were assessed after 3 weeks of mavorixafor monotherapy and after 6 weeks of combination treatment for immune cell markers by NanoString analysis for gene expression and by multiplexed immunofluorescent staining for in situ protein expression. Serum samples taken at biopsy timepoints were evaluated for key chemokine and cytokine alterations using the Myriad Rules Based Medicine multiplex immunoassays. Results: Within the TME, mavorixafor alone increased CD8+ T-cell infiltration, granzyme B signal, antigen presentation machinery, and both tumor inflammatory signature (TIS) and IFNγ gene expression signature scores. Increases in the key serum cytokines CXCL9 and CXCL10 were further enhanced when mavorixafor was combined with pembrolizumab. Adverse events (AE), as assessed by the investigator according to NCI Common Terminology Criteria for Adverse Events (v4.03), related to either mavorixafor or pembrolizumab (≥15%) were diarrhea, fatigue, maculopapular rash, and dry eye. Reported AEs were all ≤ grade 3. Conclusion/Discussion: Treatment with single-agent mavorixafor resulted in enhanced immune cell infiltration and activation in the TME, leading to increases in TIS and IFNγ gene signatures. Mavorixafor as a single agent, and in combination with pembrolizumab, has an acceptable safety profile. These data support further investigation of the use of mavorixafor for patients unresponsive to checkpoint inhibitors. Significance: Despite survival improvements in patients with melanoma treated with checkpoint inhibitor therapy, a significant unmet medical need exists for therapies that enhance effectiveness. We propose that mavorixafor sensitizes the melanoma tumor microenvironment and enhances the activity of checkpoint inhibitors, and thereby may translate to a promising treatment for broader patient populations.

Effects of ketoconazole on the pharmacokinetics of ponatinib in healthy subjects.

Ponatinib is a BCR-ABL tyrosine kinase inhibitor (TKI) approved for the treatment of chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia in patients resistant or intolerant to prior TKIs. In vitro studies suggested that metabolism of ponatinib is partially mediated by CYP3A4. The effects of CYP3A4 inhibition on the pharmacokinetics of ponatinib and its CYP3A4-mediated metabolite, AP24567, were evaluated in a single-center, randomized, two-period, two-sequence crossover study in healthy volunteers. Subjects (N = 22) received two single doses (orally) of ponatinib 15 mg, once given alone and once coadministered with daily (5 days) ketoconazole 400 mg, a CYP3A4 inhibitor. Ponatinib plus ketoconazole increased ponatinib maximum plasma concentration (C(max)) and area under the concentration-time curve (AUC) compared with ponatinib alone. The estimated mean ratios for AUC0-∞, AUC0-t, and C(max) indicated increased exposures to ponatinib of 78%, 70%, and 47%, respectively; exposure to AP24567 decreased by 71%. Exposure to AP24567 was marginal after ponatinib alone (no more than 4% of the exposure to ponatinib). These results suggest that caution should be exercised with the concurrent use of ponatinib and strong CYP3A4 inhibitors and that a ponatinib dose decrease to 30 mg daily, from the 45 mg daily starting dose, could be considered.