Anlotinib + Sintilimab

Anlotinib plus sintilimab is a Chinese-developed combination pairing a multi-kinase inhibitor from Chia Tai Tianqing (anlotinib, brand name Focus V) with Innovent Biologics' PD-1 antibody (sintilimab, brand name Tyvyt). Both drugs are separately approved in China. The combination is in Phase 2 testing for first-line advanced colorectal cancer without liver metastases under registry number NCT07398326 [1]. Note: NCT07398326 has not been confirmed in a live ClinicalTrials.gov lookup at the time of this writeup, so all trial design details below should be treated as preliminary pending verification. Colorectal cancer is a hard problem for immunotherapy because roughly 95% of patients have microsatellite-stable (MSS) tumors that do not respond to PD-1 blockade alone [2]. The commercial thesis is that anti-angiogenic pressure can re-sensitize these cold tumors to checkpoint inhibition. That hypothesis has been tested in gastric, hepatocellular, and endometrial settings with mixed results, so this trial is asking a real question rather than repackaging a settled answer.

Both components are approved drugs finding a new indication together, not novel molecules. Anlotinib (CAS 1360460-82-7 for the hydrochloride salt) is a multi-targeted TKI hitting VEGFR2/3, FGFR1, PDGFR, and c-Kit. It was approved by China's NMPA in 2018 for third-line non-small cell lung cancer and has since expanded to soft-tissue sarcoma, small-cell lung cancer, and medullary thyroid carcinoma [3]. Sintilimab, an anti-PD-1 IgG4 monoclonal antibody originally developed with Eli Lilly, was first approved in China in 2018 for classical Hodgkin lymphoma and has broadened to first-line non-squamous NSCLC, hepatocellular carcinoma, and squamous NSCLC [4]. For colorectal cancer, the combination carries no FDA breakthrough, fast-track, or orphan designation. This is a China-first program without an announced U.S. bridge. Expected readout timing has not been publicly disclosed, so estimates require trial-tracker updates rather than sponsor guidance.

Anlotinib is a small pill that blocks several receptor kinases on the surface of blood-vessel cells and tumor-support cells. The most important ones are VEGFR2 and VEGFR3, which normally receive growth signals telling new blood vessels to sprout toward a tumor [5]. Block those receptors and the tumor's blood supply strangles. It also blocks FGFR1 (another growth-signal receiver used by cancer cells) and c-Kit (used by some tumors and mast cells). Sintilimab is an antibody that removes a brake called PD-1 from T cells, letting the immune system attack tumor cells it would otherwise ignore. The combination logic rests on a biology observation from the last decade: tumors with dense, chaotic blood vessels tend to be immunologically cold, full of suppressor cells and starved of the T cells that PD-1 blockade needs to work. Normalize the vasculature with a VEGFR inhibitor, and T cells can get in. This rationale earned FDA approvals for lenvatinib plus pembrolizumab in endometrial cancer and for bevacizumab plus atezolizumab in liver cancer, so the mechanism class is among the most validated in immuno-oncology [6]. Whether it translates to microsatellite-stable colorectal cancer, where checkpoint inhibitors have consistently failed, is the actual bet.

The trial is registered as NCT07398326, a Phase 2 study of anlotinib combined with sintilimab as first-line treatment for advanced colorectal cancer without liver metastases [1]. The NCT identifier itself has not been verified against a live ClinicalTrials.gov record, so the details below are drawn from preliminary metadata and should be re-checked. The exclusion of liver metastases is unusual and worth attention. Liver-metastatic CRC has been shown to blunt response to PD-1 blockade through a hepatic tolerance mechanism: the liver is an immunologically tolerant organ that physically traps and exhausts the CD8 T cells that PD-1 blockade needs to work, so when a tumor has metastasized there, that trap depletes the very immune response the drug is trying to unleash [7]. Restricting to non-liver-metastatic disease is a design choice that biases toward responders and improves the odds of a positive signal. That is scientifically defensible and also commercially narrow: the label, if the combination ever pursues one, would apply to a subset of a subset. The sponsor is Shanghai Changzheng Hospital, an academic center, not the manufacturer. Neither Chia Tai Tianqing nor Innovent is listed as the trial sponsor, meaning this is investigator-initiated rather than a company-run registrational study. Primary endpoint, enrollment target, comparator arm, MSI/MMR stratification status, trial start date, and primary completion date are not disclosed in the available preliminary registry data. Direct ClinicalTrials.gov verification is required before any commercial modeling. The absence of a control arm and the absence of MSI/MMR stratification in most Phase 2 investigator-initiated combos in China would be the default expectation.

Our model estimates a 4% chance this drug is eventually approved. It starts from the historical base rate for Phase 2 drugs in this area (about 10%), then adjusts using ten facts about the trial and sponsor. What moves the number most: it is helped by a non-randomized design; it is held back by the sponsor's thin or weak approval record, its few secondary endpoints, and weak or limited earlier-phase results. The other facts land near average for this stage, so they leave the estimate roughly where the base rate put it.

Efficacy risk dominates. Microsatellite status is not mentioned in the available trial description, and if the study enrolls unselected CRC without stratifying by MSI-high versus MSS, any positive signal will be difficult to interpret and any negative signal will be blamed on population heterogeneity. Prior LEAP-017 data suggest MSS CRC does not meaningfully benefit from lenvatinib plus pembrolizumab, so the burden of proof on anlotinib plus sintilimab is high [9]. The most informative comparator is fruquintinib plus sintilimab. Same PD-1 antibody, different TKI, same China-first context. Fruquintinib itself is FDA-approved for refractory metastatic CRC based on FRESCO-2 (2023) [12], and the fruquintinib+sintilimab combo has produced 20-month median OS and 6.9-month median PFS in refractory MSS CRC [11]. That is a real bar. If anlotinib+sintilimab in a more favorable first-line, no-liver-mets population cannot beat those numbers, the swap of TKI adds nothing. If it clearly beats them, the trial has isolated an anlotinib-specific advantage. Safety risk is well-characterized for each drug individually: anlotinib causes hypertension, hand-foot syndrome, and proteinuria in a substantial fraction of patients, while sintilimab carries standard checkpoint inhibitor immune-related adverse events including pneumonitis and colitis. The combination increases discontinuation risk, particularly in a first-line setting where patients have less tolerance for toxicity than in later lines. Commercial risk is severe even in a positive scenario. Neither drug is approved in the United States or Europe. Innovent's attempt to bring sintilimab to the U.S. for NSCLC was rejected by FDA in 2022 on the grounds that a single-country trial was insufficient [10]. That precedent applies here. A positive China Phase 2 in CRC creates value for the domestic market and licensing conversations, but does not open a Western regulatory path without a multi-regional confirmatory trial.

This is worth watching but not a priority position. The signal that would elevate it is a disclosed objective response rate meaningfully above the fruquintinib+sintilimab MSS CRC benchmark, in a defined MSS subgroup, with progression-free survival exceeding six months. That would put the combination in conversation with the current best-in-class Chinese VEGFR+PD-1 combo rather than in its shadow. The signal that would bury it is a mixed-population readout with no MSI stratification and single-digit response rates, which would confirm that swapping fruquintinib for anlotinib in this combination adds nothing. Check back after the next major GI oncology meeting cycle, either ASCO GI in January or ESMO in the fall, when Chinese investigator-initiated combination trials typically report. Domestic Chinese competitive context matters here: apatinib (rivoceranib, Hengrui) is the incumbent Chinese VEGFR2 TKI and is being developed in combinations with camrelizumab (Hengrui's own PD-1). Chia Tai Tianqing's position with anlotinib depends on carving space among apatinib+camrelizumab, fruquintinib+sintilimab, and now anlotinib+sintilimab. Neither Chia Tai Tianqing (private, part of Sino Biopharm) nor Innovent Biologics (HKEX: 1801) is likely to build significant Western investor interest around this specific readout, but a positive result would strengthen Innovent's broader claim that sintilimab combinations are a durable franchise beyond lung cancer. For U.S.-listed comparables, the more relevant read-across is to Takeda (fruquintinib ex-China rights via HUTCHMED partnership), Merck's LEAP program status updates, and any signals from Eisai on lenvatinib franchise defense in GI tumors.