Sponsor: Stephanie Berg (other)
Phase: 2
Start date: Nov. 24, 2025
Planned enrollment: 25
Sasanlimab (PF-06801591; RN-888; WHO 11161) is a humanized IgG4 monoclonal antibody targeting programmed death-1 (PD‑1). It is being developed as a subcutaneous (SC) checkpoint inhibitor dosed most commonly at 300 mg every 4 weeks. Preclinical work showed selective, high-affinity PD‑1 binding, blockade of PD‑L1/PD‑L2, and T‑cell activation without detectable Fc‑mediated effector function. Clinical development includes a pivotal phase 3 trial in BCG‑naïve, high‑risk non–muscle invasive bladder cancer (NMIBC) and early‑phase studies across solid tumors. (pubmed.ncbi.nlm.nih.gov)
Non–muscle invasive bladder cancer (BCG‑naïve, high‑risk; Phase 3 CREST, NCT04165317)
- Randomized 1:1:1: sasanlimab+BCG induction+maintenance (Arm A; n=352) vs sasanlimab+BCG induction only (Arm B; n=352) vs BCG induction+maintenance (Arm C; n=351). Primary endpoint met: event‑free survival (EFS) improved for Arm A vs Arm C (HR 0.68; 95% CI 0.49–0.94; one‑sided p=0.0095). Estimated 36‑month EFS: 82.1% (Arm A) vs 74.8% (Arm C). Benefit was consistent in CIS and T1 subgroups. (pubmed.ncbi.nlm.nih.gov)
- Key secondary comparison (Arm B vs Arm C) was negative (HR 1.16; p=0.312), underscoring the role of BCG maintenance in the combination. In patients with CIS at randomization, complete response (CR) at any time was 89.8% with sasanlimab+BCG induction+maintenance vs 85.2% with BCG alone; 36‑month CR maintenance among responders was 91.7% vs 67.7%, respectively. Median OS not different at interim analysis (~41‑month follow‑up); study ongoing. (pfizer.com)
Advanced solid tumors (Phase Ib/II; SC 300 mg Q4W) - Dose‑expansion cohorts showed confirmed objective response rates (ORR): 16.4% in NSCLC (n=68) and 18.4% in urothelial carcinoma (n=38). Median PFS was 3.7 months (NSCLC) and 2.9 months (urothelial); median OS 14.7 and 10.9 months, respectively. Responses and survival tended to be higher with elevated PD‑L1 and high TMB. (pmc.ncbi.nlm.nih.gov)
Alternative SC dosing (Phase Ib/II) - A randomized pharmacokinetic study in advanced NSCLC/other malignancies evaluated 300 mg Q4W vs 600 mg Q6W SC dosing; it characterized exposure targets and supported SC schedules for further study. (pmc.ncbi.nlm.nih.gov)
Last updated: Oct 2025
Goal: To evaluate the antitumor activity and safety of the triplet regimen sasanlimab, palbociclib, and axitinib for patients with unresectable advanced or metastatic renal cell carcinoma with clear cell histology or translocation RCC. The primary efficacy objective is objective response rate by RECIST 1.1.
Patients: The trial is enrolling adults with measurable unresectable advanced or metastatic RCC with a clear cell component, including sarcomatoid features, or defined translocation RCC. Patients must have ECOG performance status 0–2, adequate marrow, hepatic, renal, and urine protein parameters, and be able to swallow oral medications. Key exclusions include prior systemic therapy for advanced or metastatic RCC, prior metastatic VEGF-pathway therapy, prior CDK4/6 inhibitor therapy, prior immune checkpoint inhibitor exposure except certain adjuvant use completed more than 12 months earlier, untreated or unstable brain metastases, significant autoimmune disease requiring immunosuppression, active systemic infection including HIV, active hepatitis B or C, major recent cardiovascular events, significant pulmonary disease or pneumonitis history, and use of strong CYP3A inhibitors or inducers.
Design: This is a single-arm, open-label phase 2 treatment study with planned enrollment of 25 patients. There is no randomization or comparator arm. A Bayesian dose-limiting toxicity monitoring plan is used during the first two cycles, beginning after the first three participants have initiated protocol therapy. Disease assessments are performed every 8 weeks for the first 16 weeks and then every 12 weeks while on treatment.
Treatments: All participants receive sasanlimab, axitinib, and palbociclib in 28-day cycles. Sasanlimab is a humanized IgG4 anti–PD-1 monoclonal antibody designed to block PD-1 interaction with PD-L1 and PD-L2, thereby enhancing antitumor T-cell and natural killer cell activity. Early phase 1 data in advanced solid tumors showed an acceptable safety profile across IV and subcutaneous dose levels, with preliminary responses reported in several tumor types, but it is not FDA approved for RCC. Palbociclib is an oral CDK4/6 inhibitor that blocks cell-cycle progression from G1 to S phase; it is approved in hormone receptor–positive breast cancer but not in RCC. Axitinib is an oral VEGF receptor tyrosine kinase inhibitor and is an established FDA-approved treatment option in advanced clear cell RCC. In this protocol, axitinib is taken twice daily on days 1–28, palbociclib is taken once daily on days 8–28, and sasanlimab is administered on day 1 of each cycle at a protocol-defined dose.
Outcomes: The primary endpoint is objective response rate, defined as complete or partial response by RECIST 1.1. Secondary endpoints include the rate of grade 3 or higher treatment-related adverse events by CTCAE v5.0, complete response rate, deep partial response rate defined as at least 80% reduction in target lesions by central review, median progression-free survival, and median overall survival. Adverse events are collected during treatment and for 90 days after the last dose or until initiation of a new cancer-directed therapy, and survival follow-up occurs every 6 months for up to 2 years after treatment discontinuation.
Burden on patient: The patient burden is moderate to moderately high. Treatment includes two continuous oral agents with different schedules plus clinic-based sasanlimab administration every 28-day cycle, requiring regular visits and adherence to a multi-drug regimen. Screening requires tumor tissue submission, and a new biopsy during screening is required unless suitable recent archival tissue is available; this can add procedural burden. Monitoring includes frequent imaging early in treatment, blood and urine testing, ECGs, questionnaires, adverse-event assessments, and follow-up visits, although there are no intensive pharmacokinetic sampling requirements described. Overall burden is higher than routine standard-of-care oral therapy because of the investigational triplet, biopsy/tissue requirements, close safety monitoring, and early imaging schedule.
Last updated: May 2026
Inclusion Criteria:
* Histologically or cytologically confirmed unresectable advanced or metastatic renal cell carcinoma with a clear cell component or translocation renal cell carcinoma. Patients with clear cell carcinoma and sarcomatoid histology are eligible.
* a. For tRCC please refer to the following for eligibility definitions:
* i. TFE3 (Xp11.2) translocation RCC: confirmed by IHC; however, FISH should be utilized if IHC is not optimal (ie, conclusive) or unavailable.
* ii. TFEB rearranged RCC: confirmed by FISH; TFEB amplified tumors are excluded.
* b. A formalin-fixed, paraffin-embedded (FFPE) tumor tissue block from a de novo tumor biopsy obtained during screening will be required (biopsied tumor lesion should not be a RECIST target lesion). Alternatively, a recently obtained archival FFPE tumor tissue block (not cut slides from a primary or metastatic tumor resection or biopsy) can be provided if the following criteria are met:
* i. The biopsy or resection was performed within 1 year of registration AND
* ii. The patient has not received any intervening systemic anti-cancer treatment from the time the tissue was obtained and registration onto the current study. If an FFPE tissue block cannot be provided as per documented regulations then 15 unstained slides (10 minimum) will be acceptable
* c. Availability of an archival FFPE tumor tissue block from primary diagnosis specimen (if available and not provided per above). If an FFPE tissue block cannot be provided as per documented regulations, then 15 unstained slides (10 minimum) will be acceptable.
* Measurable disease as per RECIST 1.1. See Section 11 for the evaluation of measurable disease.
* Age ≥ 18 years.
* ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A).
* Normal organ and marrow function as defined below:
* a. Absolute neutrophil count ≥1.5×109/L
* b. Platelets ≥100×109/L
* c. Hemoglobin ≥9g/dL (RBC transfusions allowed)
* d. Total bilirubin ≤ 1.5 × institutional upper limit of normal (ULN) with the following exception: patients with known Gilbert disease should have a total serum bilirubin ≤ 3 x ULN
* e. AST(SGOT)/ALT(SGPT) ≤1.5 × ULN
* f. Creatinine clearance ≥30 mL/min according to the CKD-EPI equation. (APPENDIX C)
* g. Urine protein \<1+ by urinalysis; If ≥1+ protein or otherwise suggestive of any proteinuria above a trace amount (per local institutional standards), a random urine protein and creatinine ratio (UPCR) should be collected. A 24-hour urine collection can also be utilized for direct measurement. When multiple modalities are used, the 24-hour urine measurement takes precedence over the random UPCR; refer to section 6.2 for further guidance.
* Women of child-bearing potential and men must agree to use adequate contraception (intrauterine device or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. If condoms are used as a barrier method, a spermicidal agent should be added as a double barrier protection. A negative pregnancy serum test should be obtained within 7 days of therapy initiation. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she must discontinue treatment immediately. Data on fetal outcome and breast-feeding are to be collected for regulatory reporting and drug safety evaluation. Participants treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 90 days after completion of sasanlimab, axitinib and palbociclib administration.
* Ability to swallow oral medications.
* Ability to understand and willingness to sign a written informed consent document.
Exclusion Criteria:
* Treatment with the following prior therapies:
* a. Prior systemic therapy for advanced or metastatic RCC.
* b. Prior adjuvant or neoadjuvant therapy for RCC if disease progression or relapse has occurred within 12 months of last dose of such therapy. Treatment with an immune checkpoint inhibitor in the adjuvant setting is allowed providing more than 12 months have elapsed since last dose or completion of therapy.
* c. Prior treatment with any immunotherapeutic agent (IL-2, IFN-α, anti-PD(L)-1, anti-CTLA-4, or any other antibody or drug targeting T-cell co-stimulation or immune checkpoint pathways).
* d. Prior therapy with axitinib or other therapies targeting VEGF pathway in the metastatic setting (adjuvant therapy is allowed).
e. Prior therapy with any CDK4/6 inhibitor.
* Participants with untreated brain metastases. Participants with metastatic CNS tumors may participate in this trial, if the participant is ≥ 4 weeks from therapy completion (incl. radiation and/or surgery), is clinically stable at the time of study entry and is not receiving corticosteroid therapy \>10 mg/day prednisone equivalents. A repeat MRI or CT brain to show stability is required.
* Wide field radiation therapy ≤ 2 weeks prior to treatment start. Prior palliative radiotherapy to metastatic non-target lesion(s) is permitted if completed at least 48hrs prior to patient registration.
* Untreated deep vein thrombosis or pulmonary embolism, or event of deep vein thrombosis or pulmonary embolism within 2 weeks of treatment start. Patient should be on at least 1 week of anticoagulation before C1D1.
* Major surgery/surgical procedures within the past 4 weeks prior to registration.
* The patient has serious and/or uncontrolled preexisting medical condition(s) that, in the judgment of the investigator, would preclude participation in this study (for example, interstitial lung disease - also see 3.2.22, severe dyspnea at rest or requiring oxygen therapy, severe renal impairment \[e.g. estimated creatinine clearance \<30ml/min\], history of major surgical resection involving the stomach or small bowel, or preexisting Crohn's disease or ulcerative colitis or a preexisting chronic condition resulting in baseline Grade 2 or higher diarrhea).
* Current or prior use of immunosuppressive medication within 7 days prior to registration, except the following:
* a. Intranasal, inhaled, topical steroids, or local steroid injections (eg. intra-articular injection).
* b. Systemic corticosteroids at physiologic doses ≤10 mg/day of prednisone or equivalent.
* c. Steroids as premedication for hypersensitivity reactions (eg. CT scan premedication).
* Known severe hypersensitivity reactions to monoclonal antibodies (Grade ≥3) or any history of anaphylaxis.
* Active autoimmune disease that might deteriorate when receiving an immunostimulatory agents. Patients with diabetes type I, vitiligo, psoriasis, hypo- or hyperthyroidism not requiring immunosuppressive treatment are eligible.
* Vaccination within 4 weeks of the first dose of sasanlimab and while on trial is prohibited except for administration of inactivated vaccines (for example, inactivated influenza or shingles vaccines). Note, the COVID19 vaccine is not a live vaccine and permitted.
* Grade ≥3 hemorrhage within 4 weeks of registration.
* Patient with active systemic bacterial infection (requiring IV antibiotics at the time of initiating study treatment), fungal infection, or detectable viral infection. Patients with known viral infection (such as HIV) are excluded given the potential for interactions between antiretroviral agents and palbociclib and axitinib, and the potential for increased risk of life-threatening infection with therapy that is myelosuppressive. If patients are not known to have HIV, a HIV test is required prior to registration.
* Patients with known Hepatitis B or Hepatitis C infection are excluded only if there is evidence of active infection (detectable Hepatitis B surface antigen, detectable HBV DNA, or detectable Hepatitis C RNA).
* Prior allogenic or autologous stem cell or any solid organ transplant.
* Impairment of gastrointestinal function or gastrointestinal disease that may significantly alter the absorption of oral drugs (e.g., ulcerative diseases, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome, or small bowel resection).
* Participants who are currently taking therapeutic doses of warfarin sodium or any other coumadin-derivative anticoagulant. Therapeutic use of low molecular weight heparin and factor Xa inhibitors (eg. apixaban, rivaroxaban) is permitted.
* Other malignancy diagnosed within 2 years of treatment start unless negligible risk of metastases or death according to the investigator (included but not limited to carcinoma in situ of the cervix, basal or squamous cell skin cancer, localized prostate cancer, ductal carcinoma in situ of the breast, non-muscle invasive urothelial carcinoma, or other malignancy not deemed to impact patients 5-year life expectancy).
* Has a personal history of any of the following conditions: syncope of cardiovascular etiology, ventricular arrhythmia of pathological origin (including, but not limited to, ventricular tachycardia and ventricular fibrillation), myocarditis, sudden cardiac arrest.
* Has had any major cardiovascular event within 6 months prior to treatment start, including but not limited to: myocardial infarction, unstable angina, cerebrovascular accident, transient ischemic event or New York Heart Association Class III or IV heart failure.
* Ongoing cardiac dysrhythmias of NCI CTCAE Grade ≥2 or history of long QTC syndrome. Any history of myocarditis.
* History of interstitial lung disease or other restrictive lung disease, as well as history of symptomatic respiratory condition considered clinically significant by the investigator. Individuals with a history of radiotherapy to the thorax and any history of pneumonitis will be excluded.
* Current or past tobacco users with a history of cigarette smoking greater than 30 pack-yrs (i.e., # of packs of cigarettes smoked per day × # of years patient has smoked \> 30).
* Participants with a known hypersensitivity to the study compounds or to its excipients.
* Current use or anticipated need for treatment with drugs or foods that are known strong CYP3A4/5 inhibitors, including their administration within 7 days prior to treatment start (eg. Grapefruit juice or grapefruit/grapefruit-related citrus fruits \[eg. Seville oranges, pomelos\], ketoconazole, miconazole, itraconazole, voriconazole, , clarithromycin, telithromycin, indinavir, saquinavir, ritonavir, nelfinavir, amprenavir, fosamprenavir nefazodone, lopinavir, troleandomycin, mibefradil, and conivaptan). The topical use of these medications (if applicable), such as 2% ketoconazole cream, is allowed.
* Current use or anticipated need for drugs that are known strong CYP3A4/5 inducers, including their administration within 14 days prior to treatment start (eg. Phenobarbital, rifampin, phenytoin, carbamazepine, rifabutin, 23albociclib, clevidipine, St John's wort).
* Participants who have taken herbal medications within 7 days prior to treatment start. Herbal medications include, but are not limited to St. John's wort, Kava, ephedra (ma huang), gingko biloba, dehydroepiandrosterone (DHEA), yohimbe, saw palmetto, and ginseng.
* Females that are pregnant or breastfeeding.
* Judgement by the investigator that the patient is unsuitable to participate in the study and the patient is unlikely to comply with study procedures, restrictions and requirements.
Boston, Massachusetts, 02215, United States
[email protected] / 617-632-6328
Status: Recruiting
Boston, Massachusetts, 02215, United States
[email protected] / 617-632-6328
Status: Recruiting