After reading the Wikipedia article on Telomeres, I find that the main points regarding Telomeres and the obstacles they represent to anti-aging treatments are as follows:-
1) Telomeres shorten each time a cell divides. There is no way that a cell can divide without the attached Telomere shortening.
2) Several theories, with sufficient evidence to support without proving them, state that cells become cancerous whenever they begin to divide without regard to Telomeres.
This means that there is no way that a cell can be made to keep functioning in a healthy manner without a Telomere, short of redesigning the entire functionality of the human body from the cellular level upwards. This would certainly require a Biotech rating in the double figures- perhaps this is the "True Immortality" which the rulebook refers to being around the corner at Biotech 11 or 12. The challenge for us is to think of ways to make someone immortal within the existing limits of Human phisiology.
Drug Treatments represent the lowest tech option. Research is already taking place today on how various drugs can adjust body chemistry to lengthen telomeres. Assuming that the Telomere research is accurate and heading in the right direction, then these would appear at Biotech 4-5 and improve in effectiveness with each Biotech rating increase. This also makes a theoretical possibility one of the Sci-Fi cliches that I'd always considered pure fantasy- the Anti-Aging drug which must be taken constantly, with aging resuming at the usual, or even accellerated, rate whenever someone stops taking it.
Engineered Longer Telomeres are another logical step. The subject is genetically engineered, either in vitro or by some form of retrovirus, to have longer Telomeres. This will simply make the subject age more slowly (real experiments on nematode worms gave a 20% increase in lifespan with this) without any further medical intervention. It won't make the subject immortal, as the Telomeres still shorten with each division, but it will slow the aging process down.
But neither of these will give immortality- they simply buy more time. In fact, these may simply be the explanations for the lifespans given in the rules, with Engineered Telomeres giving the base lifespan for a character's Biotech rating, and the Drug Treatments explaining the bonus that a civilisation gives.
How do we get true immortality? For that, there needs to be an active way of repairing the Telomeres, of restoring the lost length as part of an ongoing process.
Nanotechnology is the obvious solution to any Sci-Fi fan. Looking at it, this does seem to fall into the realm of an Engineering Problem rather than hitting any definite brick walls of impossibility. The setting has no Drexleran Dry Nanotech, but within a human body, able to swim around the bodily fluids and use the heat and chemistry of the host body for power, this might be workable. Release the nanites into the patient, perhaps flood the bloodstream with proteins that they can use as raw materials for repair, and let them go to work. This would require a very high rating in Nanotech, though, and be hard to justify as part of an ongoing process. It also feels a little unsatisfying, as Nanotech can be a far too convenient Deus Ex Machina in Sci-Fi these days.
After much consideration, and looking at what the various levels of Biotech can achieve, I've come up with the following as my solution to the Telomere Shortening problem:-
Tailored Proto-Viruses are a definite option in the given setting, given that at Biotech 8 a character can engineer tailored viruses at will using their own body as a Biowarfare lab. Create a tiny pseudovirus that does what all viruses do- seeks out the target cell and attaches itself. But make this one essentially a functional fragment of Telomere, that seeks out and attaches itself to the end of a DNA strand. The whole process will need tweaking a LOT, as the attachment could cause the cell to become cancerous, the ratio and distribution needs to be controlled to stop Telomeres becoming TOO long or some cells getting too many atachments and some getting none. But those both fall into what Colin calls "Engineering Problems". Set a colony of symbiotes to keep releasing them into the bloodstream- I'd put them in the bone marrow, as this is widespread and already serves this function for several other cells- and you have biological immortality.
I'd rate this as appearing perhaps as early as Biotech 8, and definately by 10. Of course, only the implanted colony requires this level, lower Biotech societies could get the technology from higher ones and have people visit hospitals to float in a tank for however many days every x number of years, with local technology stretching the time between these treatments as long as possible.