Head to head
Navitoclax against UBX0101
Two senolytics that met human beings and came back with different problems, one with a platelet toxicity that follows from its mechanism and one that matched placebo on knee pain at every dose in 183 people.
Column A
NavitoclaxNavitoclax (ABT-263), oral BCL-2, BCL-xL and BCL-w inhibitor
The most-cited senolytic in mice, and the one that cannot be given to healthy people. In its first human trial, 29 of 55 patients with lymphoid cancers had grade 3 or 4 thrombocytopenia, because platelets survive on the same protein whose blockade kills senescent cells.
Column B
UBX0101UBX0101, intra-articular MDM2 to p53 interaction inhibitor (Unity Biotechnology)
The first senolytic taken into a randomised phase 2 trial for a symptom endpoint. In 183 people with knee osteoarthritis, pain scores at 12 weeks were the same on every dose of UBX0101 as on placebo, according to the results Unity Biotechnology posted to ClinicalTrials.gov.
Side by side, on the facts we can check
| Attribute | Navitoclax | UBX0101 |
|---|---|---|
| Category | Longevity | Longevity |
| FDA status | Not approved for any indication, in any country. Investigational in oncology since 2006. No ageing or senescence indication is registered on ClinicalTrials.gov. | Not approved. Investigational; the phase 2 osteoarthritis trial completed in 2020 with results posted to ClinicalTrials.gov in December 2021, and the long-term follow-up study was terminated for inability to achieve primary or secondary study objectives. |
| Half-life | Not reported | Not reported |
| Molecular weight | Not reported | Not reported |
| Mechanism | Established in human cells and in mice: navitoclax is a BH3 mimetic that occupies the binding groove of BCL-2, BCL-xL and BCL-w, freeing pro-apoptotic BAX and BAK and triggering apoptosis in cells that depend on those proteins. In mice, that dependency is what makes senescent cells selectively vulnerable. In humans, the same dependency in platelets produces thrombocytopenia, verified in the oncology dose-escalation data. The senolytic selectivity demonstrated in mice has never been demonstrated in a person. | Established in mice and in cells: inhibiting the MDM2 to p53 interaction prevents p53 degradation, and senescent cells, which depend on suppressing p53-driven apoptosis to survive, die selectively. Delivery is by direct injection into the joint, which was intended to confine the effect to the knee. In humans, whether the injection cleared senescent cells from the joint was not established by the trials, which measured pain and function rather than senescent cell burden. |
| Human studies cited | 4 | 4 |
| Legal status, US | Investigational, not approved | Investigational, not approved |
Frequently asked questions
What is the difference between Navitoclax and UBX0101?
Navitoclax: The most-cited senolytic in mice, and the one that cannot be given to healthy people. In its first human trial, 29 of 55 patients with lymphoid cancers had grade 3 or 4 thrombocytopenia, because platelets survive on the same protein whose blockade kills senescent cells. UBX0101: The first senolytic taken into a randomised phase 2 trial for a symptom endpoint. In 183 people with knee osteoarthritis, pain scores at 12 weeks were the same on every dose of UBX0101 as on placebo, according to the results Unity Biotechnology posted to ClinicalTrials.gov.
Which has stronger research evidence, Navitoclax or UBX0101?
This database does not grade compounds. It counts what was run in people: 4 of the 7 studies cited on the Navitoclax profile were human work, against 4 of 6 for UBX0101. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Navitoclax and UBX0101 FDA-approved?
Navitoclax: Not approved for any indication, in any country. Investigational in oncology since 2006. No ageing or senescence indication is registered on ClinicalTrials.gov.. UBX0101: Not approved. Investigational; the phase 2 osteoarthritis trial completed in 2020 with results posted to ClinicalTrials.gov in December 2021, and the long-term follow-up study was terminated for inability to achieve primary or secondary study objectives..
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.